Well, it's been a while since my last blog posting... I'm sorry to say that I'm a pathetic blogger. Though I've been doing plenty of mechanism building lately, I'd like to use today's blog to yammer on about a few things modeling related.
One of the modeling forums I'm on had relatively generic topic started. One of the responses to this topic brought up freelance modeling vs. prototype modeling and how freelance modeling is viewed by some. It didn't start any flame wars, but it did make me think...
I want to start off by saying, that ANY modeling activity is good as far as I'm concerned. It doesn't matter if it is done by a world class modeler of "Prototype X" or the first time beginner just getting started in the hobby. Nobody starts out building flawless models, we all take time to get to that point. Newcomers deserve support from veterans, otherwise they would become discouraged and give up before they have a chance to get to a higher skill level.
Also, every modeler has their strengths and weaknesses. Some modelers are super structure builders, some excel at scenery, etc... Point is, few modelers are great at everything (though there are some!). I think that it is up to us to support each other, so that we can get through our own weak points. For the most part, I think online forums do a pretty good job at this.
The most important thing is that this is a hobby... It is meant for us to use this to relax, and get away from the daily grind. Having to face criticism for something that is meant as an escape really defeats the purpose of having a hobby. In short, do what makes you happy... Prototype, Proto-lance, or full on Freelance modeling. Take perfection as far as you have to be happy with your own efforts, and screw what everyone else says...
All that being said... I have been up to more mechanism building lately. Sorry, no pictures for now, maybe later.
I have built a few more of the 0-6-0 diesel mechanisms over the last few months. I've become somewhat obsessed with creating a good running equalized mechanism, that is as easy (quick) to build as it can be, while still having a high probability of running like a Swiss watch, right out of the gate.
I'd say I'm about 85% of the way there... I've had to make a few compromises to prototype fidelity to do it (wheelbase being one), but I feel that it is worth the compromise.
Other than that, I'm working on a Forney (2-4-4) mechanism for my oldest son. It's about 65% done. It sits on its drivers, but needs gears, motor and pick-ups to run. After that, I'll be building a superstructure from a kit (Chivers RC-45a) to go on top of the new mechanism.
I'm also about 75% done with a replacement mechanism for the Car Works, SR&RL #23. This locomotive was a 2' gauge 2-6-2, the heaviest of that wheel arrangement built for any US 2' RR. The original mechanism had issues... To start with, it had a pathetic 14:1 gear ratio, and no flywheel. The new mechanism features a 50:1 gear ratio, coupled to a Mashima 1220 motor and a good size flywheel.
I laser cut a new inner gearbox and frame that is equalized (I don't build rigid framed mechanisms any more). To ensure that it ran smooth, I laser cut matching side rods and new counterweights to go with it. The only concession is that the beautifully modeled backhead had to be removed to accomodate the new motor and flywheel (lots longer that the old arrangement). This wasn't a problem for the client(s) that I'm building this for.
Thankfully, the new mechanism is ridiculously smooth... Because of the size and weight of the superstructure, it really quiets down the mechanism, and it should pull like a team of oxen, once it is fully weighted.
I also finally getting to the point that I can produce/build the half dozen replacement mechanisms for Victors Scale Models HOn30, SR&RL 2-6-2 #19, that I have promised several people. I had fits getting the mechanism to fit the superstructure. I'm finally there, after three or four major changes to the original prototype mechanism. The client that receives the mechanism should be able to assemble the superstructure per the kit instructions, and it should fit down over the new mechanism with little to no adjustments.
Last thing, before I cut out for another month, or two or three... I hope to get started on my "new" layout soon. I've ordered the turnouts from a custom builder, and should have them shortly. I chose to go this route this time, because while I can build turnouts myself, my time is more valuable doing other things (like building mechanisms). To ensure that I have turnouts I am happy with, I supplied my Fast Tracks fixture to the builder, and given him pretty explicit instructions and what I was expecting. Thankfully, the builder took this extremely well, and I should get turnouts that I won't have to make any adjustments to.
That's all for now.... Until next time. See Ya!
Saturday, September 5, 2009
Monday, May 25, 2009
Time...
Don't you wish you had more time for your hobby pursuits? I know I do! I'm at a point in life where I never seem to have enough time for anything. I have three young boys (10, 7 and 4), a wife, a job and a home that always seems to need some fixing... All of this keeps me busy, so modeling time is whatever time I can scrounge on a rainy day, a holiday or whatever sleep depravation I'm willing to put up with.
I so envy those modelers that are retired, or have grown (or no) children. Those that live in apartments, condos or homes that require little to no maintenance. Or those that are independently wealthy and can afford to pay someone else to do their modeling for them... Well, maybe not that last one! Model is fun and relaxing, what's the point in having someone else do it for you? Anyway...
From a modeling standpoint, I've got a lot of the more difficult stuff under my belt. I've successfully hand built track and turnouts. I can build structures and rolling stock fairly proficiently. But most of all, I'm finally able to build locomotive mechanisms that pretty much run well the first time I put them together. So, I have the hard stuff pretty well down... All I lack now is TIME! Well, maybe not just time... I also lack the ability to finish anything... I know a lot of modelers with the same affliction. It's a lot more fun to start something new and exciting, than it is to work on something old, and boring that you know you could finish, but choose not to take that last step...
So much for that diatribe... On to modeling stuff!
From the last blog entry... I've been working on a new 0-6-0 diesel mechanical mechanism design. They are inspired by, but not a copy of the Graham Farish British N scale 08 diesel mechanical shunter. I would have really liked to purchase a two or three of the fine running Grafar locomotives for bashing, but finances are just not up to it! So, I decided to dive in and use some of the store of stock parts I have, and build something for myself. Some of you might say "why buy when you build the mechanisms that you do?...". Simple... Why build what you can much more easily buy! Maybe once I have more discretionary funds...
Moving on... I had some problems with the two mechanisms I built to the new design. They wouldn't work without binding once per driver revolution. I no longer have quartering, or crankpin squareness issues, so I think some of the problem stems from the very short wheelbase, and the equalizing beam design. To make a long story short, I reverted back to my old method of equalizing 0-6-0's, which you can see from the photos in todays blog entry. So, here they are...
I so envy those modelers that are retired, or have grown (or no) children. Those that live in apartments, condos or homes that require little to no maintenance. Or those that are independently wealthy and can afford to pay someone else to do their modeling for them... Well, maybe not that last one! Model is fun and relaxing, what's the point in having someone else do it for you? Anyway...
From a modeling standpoint, I've got a lot of the more difficult stuff under my belt. I've successfully hand built track and turnouts. I can build structures and rolling stock fairly proficiently. But most of all, I'm finally able to build locomotive mechanisms that pretty much run well the first time I put them together. So, I have the hard stuff pretty well down... All I lack now is TIME! Well, maybe not just time... I also lack the ability to finish anything... I know a lot of modelers with the same affliction. It's a lot more fun to start something new and exciting, than it is to work on something old, and boring that you know you could finish, but choose not to take that last step...
So much for that diatribe... On to modeling stuff!
From the last blog entry... I've been working on a new 0-6-0 diesel mechanical mechanism design. They are inspired by, but not a copy of the Graham Farish British N scale 08 diesel mechanical shunter. I would have really liked to purchase a two or three of the fine running Grafar locomotives for bashing, but finances are just not up to it! So, I decided to dive in and use some of the store of stock parts I have, and build something for myself. Some of you might say "why buy when you build the mechanisms that you do?...". Simple... Why build what you can much more easily buy! Maybe once I have more discretionary funds...
Moving on... I had some problems with the two mechanisms I built to the new design. They wouldn't work without binding once per driver revolution. I no longer have quartering, or crankpin squareness issues, so I think some of the problem stems from the very short wheelbase, and the equalizing beam design. To make a long story short, I reverted back to my old method of equalizing 0-6-0's, which you can see from the photos in todays blog entry. So, here they are...
The three mechanisms are all HOn30/9mm gauge... All are equalized so they will have constant wheel to rail contact. The two six wheel mechanisms are identical, except for the different counterweight/crank selection. The other mechanism is an HOn30 version of the equalized 0-8-0 I featured in an earlier blog entry.
The current 0-6-0's have a 45:1 gear ratio, which is good, but I wanted the option of more or less reduction. I've done a little redesign which will allow one of three ratios to be chosen. The ratios are 75:1, 50:1 and 36:1. For most applications, the 50:1 version will be most sufficient, but I wanted to have the option of a super slow, very powerful switcher. The 36:1 ratio is for a "road" switcher, which will allow faster speed at a given motor rpm.
With the combination of equalization, moderate gearing, a flywheel, and a great motor (the Mashima 1220), these mechanisms will run flawlessly... At some point in the near future, I'll use my wife's new digital video camera to shoot some video of some of the running qualities of the mechanisms I build... Stay tuned.
That's all for now...
Jeff
Saturday, May 9, 2009
More projects...
As always, I find myself starting more projects and not finishing others...
The Euro/UK inspired layout featured in my last blog entry is DOA... My pendulum of modeling focus has swung back to Maine Two-Foot, and I've revived my 2' x 8' model of Palermo on the WW&F Ry. I hope to bring that to a show in May of 2010.
I've been working on several mechanism projects the last month or so. I now have the design work done for a replacement mechanism for the Victors SR&RL #19 kit. I've built a prototype mechanism for a friend, and have laser cut the "production parts" for 5 more mechanisms, four of which are sold to other modelers. I'll post more on that another time.
I'm also intermittenly working on a 2-6-0 mechanism for Phillips and Rangeley #3. This locomotive was a very stubby little Baldwin Mogul. Stuffing the motor in the cab was a trick, but in the end I managed to do it, and have enough space for a small flywheel.
The latest project is a pair of HOn30 0-6-0 diesel mechanicals. They are built much like my more recent X-6-X mechanisms, featuring equalized chassis', using equalizing beams between the middle and front axles. I've laser cut enough parts for several more, both HOn30 and HOn2. I really liked the design and detailing I came up with, so I wanted to make sure I had enough parts to build many of these locomotives.
The new mechanisms have a 45:1 final gear ratio, and a Mashima 1220 can motor, with a flywheel. I've found that this is a perfect combination for my small switching locomotives with 26" drivers. Thanks to everything listed, very slow minimum speeds can be sustained with little or no stalling. Because the final ratio is fairly low (I've used up to 144:1 in the past), "road" speeds can be run at reasonable motor rpms.
These new mechanisms won't be able to manage long or heavy trains, at sub-1smph speeds, but the real ones didn't either! I've come to realize that there is such a thing as too high a gear ratio... I think for small drivered switchers, a ratio between 36:1 and 50:1 is ideal, with the absolute minimum being around 30:1.
About motors (Mashima is all I've been using)...
I've pretty much settled on the Mashima 1220 as my motor of choice. Out of the five or so I've used the last year, every one of them has operated flawlessly right out of the package. They are smooth and cog free, with a low starting rpm. I've never had one run hot, at least on my collection of ancient Troller DC power packs. For their size, they are pretty powerful, and with the proper gear ratio, they provide more torque than the weight of my small HOn2 and HOn30 mechanisms can take advantage of.
The Mashima 916 open frame motor is a good second choice, but they need a little fiddling with to get them to run optimally. I've found that the plastic brush and rear bearing casing needs to be adjusted for the smoothest operation. This can be done by loosening the two commutator brush screws, and adjusting the plastic housing at a slow speed, until the motor turns its fastest at that throttle setting. This is easier to do than to explain... You have to mess around with one to get the feel for it, but once you do, it's easy. The hardest part is tightening the brush screws without losing your new found "sweet spot". That is a "feel" thing too...
I don't care for the Mashima 1015 and 1020 motors... AT ALL!! They don't run smoothly after little use. Some have a high starting rpm (silver can), others have a lower starting rpm (brown or black can), but run faster at the top end. All seem to have an extreme sensitivity to pulsed DC voltage. That means don't even think about using them with DCC! All of them run hot... In the last five or six years, I've burnt up 3 or 4 of the 1015's, and two of the silver can 1020's.
I think there's a few factors at work here... First, the plastic brush/bearing cap on the rear of the motor, doesn't line up well with the front motor bearing. This can be adjusted, but it is tricky and often hard to maintain once the sweet spot is found. Second, the brush springs are very fine, and I question whether or not they will last long.
On the plus side, not that it matters, the 1020 is purported to be slightly more powerful than the 1220. This is most likely due to the stronger magnets in the 1020. The downside to that is higher starting voltage and rpm, and cogging.
So, I endeavor to shoe horn the 1220 into any mechanism I can... If I can't, I turn to the 916, which when adjusted properly, runs almost as well. In some situations, I will use an old Sagami 1220, which is small enough to squeeze into most HOn2/n30 Maine Two Foot prototype 2-6-2's.
I've pretty much given up on the 1015's and have sold off the 25 that I had stockpiled. The 5 or so 1020's I have, will be used for "limited use" locomotives.
Photos to come soon. That's it for now....
Jeff
The Euro/UK inspired layout featured in my last blog entry is DOA... My pendulum of modeling focus has swung back to Maine Two-Foot, and I've revived my 2' x 8' model of Palermo on the WW&F Ry. I hope to bring that to a show in May of 2010.
I've been working on several mechanism projects the last month or so. I now have the design work done for a replacement mechanism for the Victors SR&RL #19 kit. I've built a prototype mechanism for a friend, and have laser cut the "production parts" for 5 more mechanisms, four of which are sold to other modelers. I'll post more on that another time.
I'm also intermittenly working on a 2-6-0 mechanism for Phillips and Rangeley #3. This locomotive was a very stubby little Baldwin Mogul. Stuffing the motor in the cab was a trick, but in the end I managed to do it, and have enough space for a small flywheel.
The latest project is a pair of HOn30 0-6-0 diesel mechanicals. They are built much like my more recent X-6-X mechanisms, featuring equalized chassis', using equalizing beams between the middle and front axles. I've laser cut enough parts for several more, both HOn30 and HOn2. I really liked the design and detailing I came up with, so I wanted to make sure I had enough parts to build many of these locomotives.
The new mechanisms have a 45:1 final gear ratio, and a Mashima 1220 can motor, with a flywheel. I've found that this is a perfect combination for my small switching locomotives with 26" drivers. Thanks to everything listed, very slow minimum speeds can be sustained with little or no stalling. Because the final ratio is fairly low (I've used up to 144:1 in the past), "road" speeds can be run at reasonable motor rpms.
These new mechanisms won't be able to manage long or heavy trains, at sub-1smph speeds, but the real ones didn't either! I've come to realize that there is such a thing as too high a gear ratio... I think for small drivered switchers, a ratio between 36:1 and 50:1 is ideal, with the absolute minimum being around 30:1.
About motors (Mashima is all I've been using)...
I've pretty much settled on the Mashima 1220 as my motor of choice. Out of the five or so I've used the last year, every one of them has operated flawlessly right out of the package. They are smooth and cog free, with a low starting rpm. I've never had one run hot, at least on my collection of ancient Troller DC power packs. For their size, they are pretty powerful, and with the proper gear ratio, they provide more torque than the weight of my small HOn2 and HOn30 mechanisms can take advantage of.
The Mashima 916 open frame motor is a good second choice, but they need a little fiddling with to get them to run optimally. I've found that the plastic brush and rear bearing casing needs to be adjusted for the smoothest operation. This can be done by loosening the two commutator brush screws, and adjusting the plastic housing at a slow speed, until the motor turns its fastest at that throttle setting. This is easier to do than to explain... You have to mess around with one to get the feel for it, but once you do, it's easy. The hardest part is tightening the brush screws without losing your new found "sweet spot". That is a "feel" thing too...
I don't care for the Mashima 1015 and 1020 motors... AT ALL!! They don't run smoothly after little use. Some have a high starting rpm (silver can), others have a lower starting rpm (brown or black can), but run faster at the top end. All seem to have an extreme sensitivity to pulsed DC voltage. That means don't even think about using them with DCC! All of them run hot... In the last five or six years, I've burnt up 3 or 4 of the 1015's, and two of the silver can 1020's.
I think there's a few factors at work here... First, the plastic brush/bearing cap on the rear of the motor, doesn't line up well with the front motor bearing. This can be adjusted, but it is tricky and often hard to maintain once the sweet spot is found. Second, the brush springs are very fine, and I question whether or not they will last long.
On the plus side, not that it matters, the 1020 is purported to be slightly more powerful than the 1220. This is most likely due to the stronger magnets in the 1020. The downside to that is higher starting voltage and rpm, and cogging.
So, I endeavor to shoe horn the 1220 into any mechanism I can... If I can't, I turn to the 916, which when adjusted properly, runs almost as well. In some situations, I will use an old Sagami 1220, which is small enough to squeeze into most HOn2/n30 Maine Two Foot prototype 2-6-2's.
I've pretty much given up on the 1015's and have sold off the 25 that I had stockpiled. The 5 or so 1020's I have, will be used for "limited use" locomotives.
Photos to come soon. That's it for now....
Jeff
Saturday, March 7, 2009
Well now, it's been quite a while since I added something to my blog... I've been busy with various things, and have even gotten some modeling done.
The first turnout is done except for a throwbar and gapping the frog rails. I hope to build the four remaining turnouts over the next few weeks, so that once the benchwork is done, I can start in on track laying right away.
I've decided to build a new layout. My old layout "Palermo" was modeled in HOn30 after an actual stop on the Wiscasset, Waterville and Farmington RR in Maine. Palermo was a town on the line, and featured the station, three potato storage houses, and a storehouse for a local merchant. The yard was small and simple, featuring three turnouts/points, two of which were for the passing siding/loop around the station. The third was for one of the potato houses that sat west of the station, up on a slight hill.
I liked Palermo well enough, but I lost interest in it eventually... It never got beyond basic scenery and the start of the station, and three potato houses. Once I get the track down on the new layout, I'll be giving Palermo to a friend so that he can have something to run his trains on.
The new layout will also be HOn30. There was a very strong inclination to build it to HOn2/7mm gauge, but practicality eventually won out, and I decided to stick with HOn30/9mm gauge. An HOn2 layout would have been great, but my two best modeling friends model HOn30, so for the sake of interchanging equipment with them, HOn30 won out.
Shown below is the trackplan and a few photos of the first turnout and concept sketch for scenery and structures. The layout will be 18" x 72" and will have a 7.5" x 36" long sector plate and fiddle yard with removable cassettes off the back of the layout. The minimum radius for the layout is set at 22" for the curved quay headshunt. All other curves are in the 36" to 60" range, with the exception of the turnout diverging route, which is 23".
Speaking of turnouts, I'm using a Fast Tracks HOn30 Code 55/#6 turnout fixture to build the turnouts/points for it. I'm nutty about turnout precision, and don't trust my skill freehanding turnout construction, so I use a fixture. To add to this, most manufactured turnouts available for HOn30 or N gauge (which are not many) don't make the grade (for the most part, Atlas' new N scale #7 and #10 are pretty good, but they are hard to disguise for HOn30)... Their flangeways are too wide, or their diverging radii are too small.
As a side note... Many modelers balk at the price of the Fast Tracks fixtures. My take on this is that track and locomotive mechanisms are the two MOST important elements of our model railroad. Extra added expense for obtaining excellent track and mechanisms is well worth the investment. Nobody should spend hours and hours building a model RR, only to be frustrated because nothing runs and the trains don't stay on the tracks! Static displays of scenery, structures and rolling stock are not really what this is about...
Most of the track will be hand built using Micro Engineering Code 55 rail, and PCB ties. I plan to use Atlas N scale Code 55 flextrack anywhere the ties won't be seen, which means the fiddle yard, and any track buried by simulated concrete, brick or otherwise. This was one of the benefits of modeling HOn30 vs. HOn2...
The layout is going to have a waterfront theme and use influences from the New England/Maine coastline, as well as some ideas from a few well known British and European OO9 layouts.
I plan to use a few diesel mechanicals to move/switch/shunt cars around the layout. I have several mechanisms built or in the process of being built, that would be very suitable for such a layout. For the time being, the layout will be DC. I have a high end, custom DC throttle that is supposed to provide exceptional running quality for small DC can motors, and I want to give it a go. Truthfully, I'm not sold on "merits" of DCC, but I want to leave DCC as an option for the future, and the turnouts will be built/wired as "DCC friendly".
The first turnout is done except for a throwbar and gapping the frog rails. I hope to build the four remaining turnouts over the next few weeks, so that once the benchwork is done, I can start in on track laying right away.
That's it for now....
Saturday, August 2, 2008
Distractions...
With the 0-8-0 mechanism running well off a power pack (no wheel pick-ups yet), I turned my attention to something else. Quite a long time ago, I started building an HOn2 0-4-0, but stopped before it was finished. Two nights ago I decided to take up the project again, as it fits in with my new found desire to model HOn2 again... The photos below show where I'm at so far.
What you see is a small 120:1 gear ratio, side rod driven mechanism. The motor will be a Mashima 916 open frame, that will drive the rear drivers through a double set of worms and worm gears. The first worm gear has 10 teeth, and the axle worm gear has 12 teeth, with the total reduction being 10 x 12 = 120. This form of gearing results in extremely high torque, but the downside is extremely slow top speed. This mechanism is built for super slow speed switching.
The motor will be mounted vertically in the cab, leaving the hood wide open for detailing or weight. There's enough room to stuff a good sized chunk of lead under the rear of the hood, and a "diesel engine" up front. As with all my mechanisms, this one is equalized. The front/non-geared axle can pivot from side to side, allowing all four wheels to seat on the railhead, at all times.
Here's a progress photo of the 0-8-0...
What you see is a small 120:1 gear ratio, side rod driven mechanism. The motor will be a Mashima 916 open frame, that will drive the rear drivers through a double set of worms and worm gears. The first worm gear has 10 teeth, and the axle worm gear has 12 teeth, with the total reduction being 10 x 12 = 120. This form of gearing results in extremely high torque, but the downside is extremely slow top speed. This mechanism is built for super slow speed switching.
The motor will be mounted vertically in the cab, leaving the hood wide open for detailing or weight. There's enough room to stuff a good sized chunk of lead under the rear of the hood, and a "diesel engine" up front. As with all my mechanisms, this one is equalized. The front/non-geared axle can pivot from side to side, allowing all four wheels to seat on the railhead, at all times.
Here's a progress photo of the 0-8-0...
Wednesday, July 30, 2008
As most of my modeling friends know, I'm a "hot and cold" modeler... I'm either really into it (hot) or completely out of it (cold). For now I'm "hot" and when I'm like this, I get stuff done...
Last night I set to fixing the problems that the mechanism had. I first started by moving the gear over on the axle, and shortening the bearing that was two long. This took a few tries to get it just right, but I finally prevailed and the gearbox and geared axle turned over very smoothly.
However, to do this, I had to disassemble the chassis, remove the side rods and press off the counterweights an wheels. In the process of trying to press on/quarter the new counterweights, I damaged my quartering fixture... This took an hour or so to fix, which put off reassembly of the chassis into the very late hours of the night (on a weekday, not good...). After fixing the quartering fixture, I (correctly) determined that it would be a good idea to check the quarter of the other three drivers. Long story short, the "fix" or modification to the fixture, caused it to be different enough than the already quartered drivers, that I had to requarter everything...
A quick note here... Quartering drivers, counterweights or flycranks for HOn2/n30 or OO9 locomotives requires a great deal of precision. The slightest variation from one driver set to the next equals a bind, and it does not take a lot of variation to do this, because the crank throws are so short. When quartering, it helps greatly to develop a very specific and defined order of assembly, and stick to that order for each driver set being made for a given chassis. This gives repeatability, which is just as important as precision. Even if a driver set may be out of perfect quarter, as long as each set in a given chassis is out the same, then it should work fine. I'm on my fifth quartering fixture design now, and have just about worked all the bugs out of them, so that I can get good results consistantly.
Once I had all the drivers requartered, I threw them back into the frame and proceeded to install the side rods again. Once that was complete, I oiled around a bit, and spun the drivers with my finger and "Viola", success!
The mechanism was still smooth... With the axle gear and bearing fixed, I was able to throw on the gearbox, and install the motor (temporarily, the chassis still needs pick-ups). Under power the mechanism is very smooth, even at the slowest speed the motor will turn at (which is pretty darn slow). At higher RPM, the motor is a little noisy, and has some vibration, but it's far better than most iron core motors out there in this size. Overall, I like the motor I've chosen so far... It can turn at really low RPM, and it doesn't cog. It is also smooth and quiet enough at higher speeds, that will enable the mechanism to travel at "road" speeds without too much noise. I'm not sure how much power the motor will have, but with the 45:1 gear ratio, it should boost it enough to do what needs to be done with it.
That's all for now....
Last night I set to fixing the problems that the mechanism had. I first started by moving the gear over on the axle, and shortening the bearing that was two long. This took a few tries to get it just right, but I finally prevailed and the gearbox and geared axle turned over very smoothly.
However, to do this, I had to disassemble the chassis, remove the side rods and press off the counterweights an wheels. In the process of trying to press on/quarter the new counterweights, I damaged my quartering fixture... This took an hour or so to fix, which put off reassembly of the chassis into the very late hours of the night (on a weekday, not good...). After fixing the quartering fixture, I (correctly) determined that it would be a good idea to check the quarter of the other three drivers. Long story short, the "fix" or modification to the fixture, caused it to be different enough than the already quartered drivers, that I had to requarter everything...
A quick note here... Quartering drivers, counterweights or flycranks for HOn2/n30 or OO9 locomotives requires a great deal of precision. The slightest variation from one driver set to the next equals a bind, and it does not take a lot of variation to do this, because the crank throws are so short. When quartering, it helps greatly to develop a very specific and defined order of assembly, and stick to that order for each driver set being made for a given chassis. This gives repeatability, which is just as important as precision. Even if a driver set may be out of perfect quarter, as long as each set in a given chassis is out the same, then it should work fine. I'm on my fifth quartering fixture design now, and have just about worked all the bugs out of them, so that I can get good results consistantly.
Once I had all the drivers requartered, I threw them back into the frame and proceeded to install the side rods again. Once that was complete, I oiled around a bit, and spun the drivers with my finger and "Viola", success!
The mechanism was still smooth... With the axle gear and bearing fixed, I was able to throw on the gearbox, and install the motor (temporarily, the chassis still needs pick-ups). Under power the mechanism is very smooth, even at the slowest speed the motor will turn at (which is pretty darn slow). At higher RPM, the motor is a little noisy, and has some vibration, but it's far better than most iron core motors out there in this size. Overall, I like the motor I've chosen so far... It can turn at really low RPM, and it doesn't cog. It is also smooth and quiet enough at higher speeds, that will enable the mechanism to travel at "road" speeds without too much noise. I'm not sure how much power the motor will have, but with the 45:1 gear ratio, it should boost it enough to do what needs to be done with it.
That's all for now....
Monday, July 28, 2008
Two Steps forward, three steps back...
Well tonight I found that the HOn2 0-8-0 mechanism wasn't a complete success... The gearbox has issues. Normally I have good luck with the gearbox end of things. but for some reason, probably because the rods, counterweights, etc, worked so well the first try, something else had to go wrong.
The first problem with the gearbox was the motor mount... I used a CAD file for one from a previous mech, not realizing that I had put a 0.003" offset into it. This caused the worm to be too tight against the worm gear in the new mech, which caused a bind. I fixed that by laser cutting a new motor mount today at work, and soldered it on tonight. After several tries at getting the motor mount square against the gearbox, I finally get it, and with the worm gear installed, things run smoothly with power to the motor.
With that fixed, I installed the next gear, which is really two gears, one that mates with the worm gear, and a much smaller one that mates to the axle gear. It could be called a "compound gear". It's these two gears that give the mechanism its relatively high final gear ratio. Anyway, I install the compound gear, then run the motor again... Everything runs smoothly.
I then try to install the gearbox onto the rear (geared) axle. It won't fit! For some reason, I didn't press the axle gear onto the axle far enough off center to clear one of the gears in the gearbox. I managed to press it over slightly without doing any damage. Still no-go. I didn't remove enough length from the axle bearing opposite the axle gear. The causes the two bearing faces and the axle gear to be too tight in the gearbox. Ugh!!! Now the side rods must be stripped off, one counterweight pulled, the insulated wheel removed, and the offending bearing removed and shortened. Hopefully once I get everything back together, the basic chassis will work as well as it did the first time.
Also on the list of things to fix... I need to turn a new main pivot for the front two axles. I realized today that it was bored out 1.5mm, but the pivot rod is only 1.2mm, so there's a lot of slop in there. No big deal, just more work.
I also spent some time today on designing (and cutting the parts for) the next 0-8-0 mechanism... The current mech, has about a 94.5" wheelbase in HO. It more closely represents a 2400mm wheelbase chassis to match that of a German Feldbahn 0-8-0 steam engine I kind of fancy.
The new chassis has an 87" wheelbase (7' 3"), to match the wheelbase of a Baldwin built 2ft 0-8-0 steam engine. Baldwin built four of these for a Chinese 60cm gauge railway in the 1920's. The design work proved it can be done using the construction method I used on the previous mech. So, I cut the parts for it this afternoon after I punched out...
I hope to start building the next 0-8-0 as soon as I get the first one running, at least off a power pack, but not necessarily on the track (I hate installing pick-ups).
That's all for now... More another day.
The first problem with the gearbox was the motor mount... I used a CAD file for one from a previous mech, not realizing that I had put a 0.003" offset into it. This caused the worm to be too tight against the worm gear in the new mech, which caused a bind. I fixed that by laser cutting a new motor mount today at work, and soldered it on tonight. After several tries at getting the motor mount square against the gearbox, I finally get it, and with the worm gear installed, things run smoothly with power to the motor.
With that fixed, I installed the next gear, which is really two gears, one that mates with the worm gear, and a much smaller one that mates to the axle gear. It could be called a "compound gear". It's these two gears that give the mechanism its relatively high final gear ratio. Anyway, I install the compound gear, then run the motor again... Everything runs smoothly.
I then try to install the gearbox onto the rear (geared) axle. It won't fit! For some reason, I didn't press the axle gear onto the axle far enough off center to clear one of the gears in the gearbox. I managed to press it over slightly without doing any damage. Still no-go. I didn't remove enough length from the axle bearing opposite the axle gear. The causes the two bearing faces and the axle gear to be too tight in the gearbox. Ugh!!! Now the side rods must be stripped off, one counterweight pulled, the insulated wheel removed, and the offending bearing removed and shortened. Hopefully once I get everything back together, the basic chassis will work as well as it did the first time.
Also on the list of things to fix... I need to turn a new main pivot for the front two axles. I realized today that it was bored out 1.5mm, but the pivot rod is only 1.2mm, so there's a lot of slop in there. No big deal, just more work.
I also spent some time today on designing (and cutting the parts for) the next 0-8-0 mechanism... The current mech, has about a 94.5" wheelbase in HO. It more closely represents a 2400mm wheelbase chassis to match that of a German Feldbahn 0-8-0 steam engine I kind of fancy.
The new chassis has an 87" wheelbase (7' 3"), to match the wheelbase of a Baldwin built 2ft 0-8-0 steam engine. Baldwin built four of these for a Chinese 60cm gauge railway in the 1920's. The design work proved it can be done using the construction method I used on the previous mech. So, I cut the parts for it this afternoon after I punched out...
I hope to start building the next 0-8-0 as soon as I get the first one running, at least off a power pack, but not necessarily on the track (I hate installing pick-ups).
That's all for now... More another day.
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