Machine Shop / Locomotive Drive Work

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R.K. Maroon
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Re: Machine Shop / Locomotive Drive Work

Postby R.K. Maroon » Sat Feb 18, 2017 11:55 pm

I started this thread with a question regarding the milling of some brass bar stock and the problems I was having getting a good clean cut. There were a lot of good suggestions, to which I thank all. I should say that I was not plunge cutting but taking very light surface cuts -- maybe 0.010 at a time (not wanting to break the small tool). I understand the idea that the tool RPM should increase with small bits -- I had the speed on maximum. It was suggested that the wood base I was using to secure the piece was simply not heavy or rigid enough, and I am thinking there may be some truth in that -- I used a piece of scrap pine instead of hardwood (and me with a bin full of scrap maple). However, rather than pursuing it further, I took Jay's comment to heart about not risking a fine tool to do work that could be done in another way. So I saw-cut the pieces and then finished them with a stout 1/4-inch end mill. I even found that simply using a disk sander for certain cuts was the right way to go. I have a small desktop sander with a miter guide that produces a surprising clean and accurate 90 angle.

I was cutting the bar stock as I needed two sets of chassis bolsters for an older pair of CLW Alco PAs. The later versions of the PA look like this:

PA Chassis Bolsters.jpg
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I don't actually own the pair shown (I sold the kit they were in last year), and the units I am working on are built a little bit differently (originally came with fiber bolsters), so I had to both design and fabricate my own. I could have milled them out of solid stock, but I decided to build them up instead from bar stock. In this photo, the four cut pieces are on the right:

Chassis Bolster.jpg
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The cast pieces at the top center and top left are from a CLW FA chassis kit I have. These were helpful in thinking the project through. One of the completed pieces (less holes) is at the bottom left. I used my resistance soldering unit to join the four parts:

'
Resistance Soldering.jpg
Resistance Soldering.jpg (145.06 KiB) Viewed 6697 times

I have the same general regard for my resistance unit as I do for my machine tools -- I am not an expert at any of them, so look forward to any chance to try something new. I had not tried to build up something heavy this way before and I was very pleased with the performance of the resistance unit (a five-hundred watt max, variable-power American Beauty that is also serving as a weight to hold the jig in place in the photo). At about half power, the pencil and ground clip arrangement not only flowed the solder between the pieces in about five seconds, but it made it really easy to hold the pieces firmly together and in position as I went (tough to do with a torch). I should mention that this is the front bolster. The rear is only two pieces and much easier.

Fun Stuff
Jim
Slow progress is better than no progress

Jay Criswell
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Re: Machine Shop / Locomotive Drive Work

Postby Jay Criswell » Sun Feb 19, 2017 2:53 am

Where's the "Like" icon?

Jay

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R.K. Maroon
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Re: Machine Shop / Locomotive Drive Work

Postby R.K. Maroon » Wed Mar 01, 2017 11:11 pm

Thanks for the kind words, Jay. I managed to distract myself with other projects but I finally got the other three I need built. I decided to bead-blast them to clean them up and thought they turned out nicely:

Blasted Bolsters.png
Blasted Bolsters.png (404.14 KiB) Viewed 6628 times

Hmm...well, the improvement would be more obvious if I had a before and after version side by side. For somebody like me that does mostly restoration work, I find a media blasting cabinet to be a very convenient "tool" to have. It helps to have a decent air compressor too. A friend of mine gave me a good size Craftsmen unit on moving from a house to an apartment. It's bigger than I would have bought, but it will easily keep up with continuous blasting at 40 psi (I haven't tried higher settings -- so far no need).

Jim
Slow progress is better than no progress

bob turner
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Re: Machine Shop / Locomotive Drive Work

Postby bob turner » Wed Mar 01, 2017 11:39 pm

Do you need my modified nose?

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R.K. Maroon
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Re: Machine Shop / Locomotive Drive Work

Postby R.K. Maroon » Sat Mar 04, 2017 10:41 pm

bob turner wrote:Do you need my modified nose?

That's a good question, Bob -- not because I am interested in modifying these PAs my self, but so as to better understand the issue. If I recall correctly, there is some problem with the front windows -- too large or raked back too much or something. But I also recall that the nose is supposed to have a slight taper when looking from the top, but the later CLW nose is straight. How much of this do I have correct, and would you please fill in the details please?

In the meantime, I started this thread with some drive work on a USH SD45 that, like the PAs, is passing through my shop. While I had the resistance unit out for the PA bolsters I did some repair work to the body of the SD. Here is an example of the work that needed to be done:

SD45 chassis work.png
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This is the underside looking at one of the corner step assemblies. The unit arrived to me with both ends damaged -- pushed in and a bit busted up. The previous owner made an attempt to repair this, but managed only to get blobs of solder everywhere. This gave me a chance to use my "small" resistance probe for the first time. It took a while to get the heat setting correct and find a technique that worked for me, but after a while I figured it out and things went pretty well from there. Here it is, temporarily reassembled to check coupler height:

SD45 assembled.png
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The handrails and stanchions have been replaced on this. The work in not all that well done, but I will leave it to the next owner to decide to change it or not. The local club is setting up the layout here in a couple of weeks, so I am going hang on to this until then to test run it and see how the Toyota tube drive works under load and on curves.

Jim
Slow progress is better than no progress

bob turner
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Re: Machine Shop / Locomotive Drive Work

Postby bob turner » Sat Mar 04, 2017 11:24 pm

You get the nose. Give me a week to carve the windows for you.

stephen neill
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Re: Machine Shop / Locomotive Drive Work

Postby stephen neill » Sun Mar 05, 2017 11:55 am

Jim -
The accepted story on the nose is that when Bob wanted to do the FA's he tried to modify the PA nose pattern to use for the FA's and it was damaged beyond repair in the process; I don't know whether Bob was actually doing the work or someone else. So a new PA nose pattern was made. The original pattern had the proper taper on the sides; the new one didn't.

It becomes more of a "forgivable" mistake when you understand that just 2-3 years ago Key was planning to do new PA's and they were going to do strait sided noses, insisting for quite some time that that was correct, even though there were howls of protest from the knowledgeable PA guys that they were wrong, wrong wrong. Fortunately Key came around to the right way of thinking before it was too late. I mention this only to put it in perspective. If anyone thinks I'm wrong on the Key story, please say so.

Steve

bob turner
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Re: Machine Shop / Locomotive Drive Work

Postby bob turner » Sun Mar 05, 2017 1:18 pm

I concur with the Key story. Did not know the CLW story, but Bob Smith was very sensitive about that nose.

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R.K. Maroon
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Re: Machine Shop / Locomotive Drive Work

Postby R.K. Maroon » Tue Jun 05, 2018 12:04 am

Here's a bit of recent fun:

Chucking Reamer 01.jpg
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I have possession of a good number of Allan Wehrle's old machine tools, including a nice selection of "chucking reamers". I knew from my the machine shop days (of my mostly-wasted youth) what a ream was, but I had no recollection of the concept of a chucking reamer. A bit of internet searching confirmed what I suspected, which was that chucking reamers are designed for use in drill presses, mills, and lathes. Unlike a hand ream, which is what I remember, a chucking reamer is designed to be used as speed.

So a pair of Walthers cast white metal tender trucks arrived on the workbench recently with terribly rusted wheelsets. The axles were pointed, which I thought was common, but an inventory of my spare wheelsets produced nothing that would fit (the Walthers axles seem to be longer than Athearn or other similar pointed-axle sets). So I decided to spin some bushings and convert the trucks to straight axles. I know that brass is not at all ideal for journal bushings but I knew that this particular locomotive would not see significant hours of run time (not having a layout, none of my models ever do), and I had brass in hand, so what the hey -- brass bushings it is. There was a #41 chucking reamer in Allan's collection, which I calculate to be a perfect size for standard 3/32" diameter axles (which might explain why Allan owned it), so that gave me a chance to try it out. Here is a closeup:

Chucking Reamer 02.jpg
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I drilled the stock out a few thousands undersize and the ream work beautifully. I didn't expect trouble with soft brass but you never know until you try it. As an aside, the lathe is a Unimat that belongs to the club. I have a Taig that originally passed through Sarge's shop before landing in Texas that I really like, but for very small pieces the Unimat is a little easier to use -- especially when it comes to getting those easy-to-drop items chucked up.

Life is good -- I will say that the machine shop class part of my youth making parts was not part of the wasted part. :mrgreen:
Jim
Slow progress is better than no progress

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R.K. Maroon
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Re: Machine Shop / Locomotive Drive Work

Postby R.K. Maroon » Wed Jun 06, 2018 5:20 pm

.
Here is one of the sideframes with one bushing pressed in:

Bushings.jpg
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I cleaned up the journal holes with a twist drill (and increased their depth a bit), and then sized the bushings for a friction fit into the sideframes. I did not see a need for a true interference fit. Note that I put a slight taper on end of the bushing. This made it easier to start and also provided some relief for the drill angle at the bottom of the journal hole.

It all looks relatively simple and straightforward, and it is. I imagine with a turret lathe you could do several in a minute and that an automatic screw machine could do a hundred a minute, but to do eight by hand with a standard lathe took me a couple of hours. The next eight would go much faster, of course, but I only needed eight so that's that.

Jim
Slow progress is better than no progress

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R.K. Maroon
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Re: Machine Shop / Locomotive Drive Work

Postby R.K. Maroon » Thu Jun 07, 2018 11:45 pm

I imagine many of the old hands here have ordered axles from NWSL at one point, but until recently I had not. Their catalog has A LOT of different axles listed, and I always wondered if they kept them is stock. The answer is no. I placed an order for quantity 88 shouldered axles of the type commonly found on their passenger car wheelsets. It took two months for them to arrive:

NWSL Axles 01.jpg
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NWSL Axles 02.jpg
NWSL Axles 02.jpg (666.25 KiB) Viewed 6224 times

I bought these to replace the pointed axles that came with a good number of surplus NOS NWSL wheelsets I picked up cheap a while back. I need to gin up a gauging jig for pressing the wheels on, so if anybody has some suggestions I am all ears.

Jim
Slow progress is better than no progress

Jay Criswell
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Re: Machine Shop / Locomotive Drive Work

Postby Jay Criswell » Fri Jun 08, 2018 12:10 am

I usually make my own anymore but one of the tools I find very handy is a gauge block. I will attempt to attach a link to the P:48 versions I sell through Right-O'-Way. I wasn't sure if I should post this but, because what I have is for P:48 the actual part doesn't apply to what you're doing. The concept does. For regular O Scale I made one from 1" Delrin rod. Use the lathe to cut to length and the mill to cut out the slot.

http://www.right-o-way.us./manager/imag ... C-106G.jpg

There is more to the actual assembly and I'd be happy to share how I do it.

Jay

rrjjf
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Re: Machine Shop / Locomotive Drive Work

Postby rrjjf » Fri Jun 08, 2018 6:20 am

Carey,

If you lathe is equipped with a set of headstock collets, making bushings and axles is pretty simple. I use drill rod quite often to make axles.

I have made a lot of very small parts over the years on my 9" South Bend lathe including some very small threaded (0-80) handrail posts by holding the work piece in a collet. It is great to see you enjoying the use of your machine tools. This kind of work is how I spend a good deal of my hobby time now.

Joe
Joe Foehrkolb

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R.K. Maroon
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Re: Machine Shop / Locomotive Drive Work

Postby R.K. Maroon » Fri Jun 08, 2018 10:26 am

Jay Criswell wrote:There is more to the actual assembly and I'd be happy to share how I do it

Jay -- Thank you for posting the photo. I actually have a short piece of 1" Delrin rod (somewhere), so I am very interested in the gauge block. There must be some trick to how you use it as it is not obvious to me just by looking at it. So if would, please share the assembly details and I will give it a try.

rrjjf wrote:If your lathe is equipped with a set of headstock collets, making bushings and axles is pretty simple.


Joe, my Taig mill has a small collet set in common fractional sizes:

Collets.jpg
Collets.jpg (669.1 KiB) Viewed 6196 times

These are absolutely great for holding cutting tools. However, my memory is that the chuck for these does not fit the spindle on the Taig lathe. I may be wrong about this so I will double check. I can see that having collets for a lathe could be very useful for making multiple copies of the same part.

Jim
Slow progress is better than no progress

Jay Criswell
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Re: Machine Shop / Locomotive Drive Work

Postby Jay Criswell » Fri Jun 08, 2018 11:06 am

Jim,

The collets will give you the accuracy needed for making axles that you'll never get with a 3 or 4 jaw chuck. You may need a collet holder for your lathe. I assume Taig, or some other after market company, makes them. Run out is your enemy.

Jay


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