Lurkio
Seasoned Member
Posts: 101
|
Post by Lurkio on Mar 14, 2007 20:52:03 GMT
Hi all,
Now I'm a long way off quartering any wheels, and I know some of you chaps (and chapesses) are dab hands at it, and have built engines by the dozen. So forgive my ignorance in this matter.
But I find it interesting in this and other threads that Loctite appears to be the preferred way of locating wheels on axles.
Whereas in my own experience 'in the trade', Loctite was seen as a secondary fix, perhaps as a repair, or was used on a sloppy (poorly made) fit. In other words, Loctite was considered something of a short cut, and frowned upon at times.
(I realise that Loctite's now widely used in industry, though).
In our hobby, I would have thought it preferable, especially on the larger scales, to provide keys/pins to axles as a matter of course. That's 'proper' engineering, isn't it? And though it does take a bit of extra effort to set up, it's only got to be done once - the wheels can be removed and replaced without loss of setting - a 'proper job' in the end from an engineering point of view. Or am I out of touch?
I'm not criticising - I haven't the experience in the hobby to do so.
Just wondered what you more experienced model engineers think. When (if) I ever get around to quartering, I intend to key - if you're interested! And yes...I do have a couple of bottles of Loctite knocking about!
Lurkio.
|
|
|
|
Post by Deleted on Mar 14, 2007 22:15:13 GMT
Hi
The method using the coupling rods is an old LBSC method as far as I know.
I used it when I made a new crank axle for my part built 4F, so that the quartering matched the existing coupled wheels.
LBSC recommended press fits which seem to be out of favour for some reason, but the method is basically fit one wheel to each axle, put the second wheel on the driving axle, by eye, try square or whatever.
Assemble chassis fitting the coupling rod on one side, then using press fits, but with a very slight taper so the wheels can be started on the axles as a nice push fit, assemble the second side. (I think an extra long driving crankpin would help for this bit)Spin the wheel sets, making any adjustments as required, when everything works as it should remove the axles and press the wheels on fully. The method should work with loctite, but probably only doing one wheel at a time. When everything is as it should be the wheels can be pinned.
I've never seen it recommended, but if the wheels were made a hand push fit on the axles, they could be adjusted easily using the coupling rods, when everything is possitioned correctly, the wheels could be secured with the thin 'wicking'grade of strong loctite that is able to creap into even a press fit, and then pinned for good measure.
Making axles and wheels with keyways requires accurate work to get a good result, making jigs can be a lot of extra work if only one loco is being made, LBSC's methods are not aimed at making quantities of interchangable components as in industry, but they are very good for the inexperienced with limited equipment to be able to make parts fit together and work.
When I read that LBSC was in charge of a factory in the first world war, with 19 completly untrained women working for him, It suddenly dawned on me, why he had all these practical methods of working that didn't require accurate measurement or loads of training.
Hope this helps, sadly I don't have the gift of being able to explain things as clearly as LBSC
Regards
Trevor
|
|
|
|
Post by gilesengineer on Mar 15, 2007 8:18:09 GMT
On the subject of pinning or keyways, I put a hand drill in centred on the axle/wheel joint, and then knock a slightly tapered silver steel pin in. This does much the same a key, insofar as it provides accuarate location if you do have to remove the wheel. If pushed, I would heartily agree that the conventional slotting of keyways is the 'proper' and best way of doing it, but I have been tried very hard to use as simple techniques as possible. Ultimately, the proof is in the pudding, and 'Alice' has done many hundreds of miles and worn out her wheels once already - all without quartering problems. Of course, quartering outside cranks this way is as easy as pie....! www.tenandaquarter.comRegards Giles |
|
|
|
Post by teakfreak on Mar 15, 2007 14:20:28 GMT
I can't see why people find the use of the lathe for quartering difficult if using loctite. I use a magnetic stand base on the bed of the lathe as one stop and packing on the cross slide - works fine for me!
|
|
|
|
Post by Shawki Shlemon on Mar 16, 2007 10:22:48 GMT
I made a quartering jig from information in live steam many years ago and used it many times . The loctite is only step 1 as after the wheels are loctited then axle is pinned to the wheels. The pins do the locking .The important thing is the wheels are push fit and not loose on axle , therefore the loctite is not doing much anymore . I never had a single problem in this area .
|
|
|
|
Post by ron on Mar 17, 2007 11:15:12 GMT
Well so far so good, that's the driving and trailing wheels quartered using the conrod blanks, it was very easy, I took a great deal of time and effort to make sure the the conrod holes were spot on for length, so it turns over nice and smoothly with no binding. So far I can't see any snags. They are just Loctited at present, but I don't really feel comfortable with that so when they are all done I'll pin them as suggested. I'll do the leading pair this afternoon or tomorrow.  Ron |
|
|
|
Post by gilesengineer on Mar 17, 2007 18:20:57 GMT
Best of luck, Ron!
Giles
|
|
|
|
Post by ron on Mar 18, 2007 20:21:19 GMT
That's the front pair quartered now, didn't go quite as smoothly, I had a senior moment and forgot to fit the pump eccentric  I am now most impressed with Loctite, I had a helluva job getting the wheel back off this morning, anyhow it's all sorted now and all the wheels are quartered and it all turns over smoothly. This does seem a very easy and accurate method of quartering wheels, doing it initially in a cold workshop helps if you have any doubt about Loctite as it slows the setting time down considerably, there are graphs of time v temp for the various grades on their website. Ron |
|
|
|
Post by chameleonrob on Mar 18, 2007 20:46:26 GMT
T doing it initially in a cold workshop helps if you have any doubt about Loctite as it slows the setting time down considerably, Ron right weather for loctiting then, I'm glad it worked out so well. rob |
|
|
|
Post by Peter W. on Mar 19, 2007 20:02:47 GMT
I had a helluva job getting the wheel back off this morning, anyhow it's all sorted now Ron How did you get the wheel off ? P.S. Thanks for mentioning a cold workshop -- I wouldn't have thought of that to get more time. |
|
|
|
Post by ron on Mar 23, 2007 17:13:51 GMT
Hi
I looked up the Loctite website and they said the grade I used should separate easily at 250C, yeah right! I put a propane flame on the axle shaft, had several attempts wearing welders gloves to separate them manually without joy, I was about to bore the axle out and make a new one when I had one last go with the torch, this time I manages to drift the axle out by supporting the back of the wheel properly in a Workmate and using a hammer and brass drift, even at that it was very tight to begin with.
Ron
|
|
|
|
Post by chameleonrob on Mar 23, 2007 20:58:57 GMT
Hi they said the grade I used should separate easily at 250C, yeah right! Ron as compared to a press fit?, at least it means that if it gets that hot in service it won't just drop off. I've taken locktited wheels off a couple of times and with steel disk wheels and axles I heat the end of the axle and keep the heat on till the other side of the wheel is blue, that way I can be sure the entire joint was at a high enough temperature rather than just the surface. rob |
|
