Peter,if you have a face plate you can clamp both to it so long as the plates miss the bed you can centre and bore.

Frank

Correct, it won't be. You won't be a mile out, but it's not going to hold a thou or so. Best thing is to make a simple jig to hold the individual axleboxes for boring. This is what I did for my traction engine crankshaft beaings:

Of course it's a bit more complex as it also utilises the bearing housings, but it shouldn't be difficult to come up with a simplified design.

Andrew

I would do as Duncan suggests, but I would make the coupling rods first. Next make the discs the same diameter as the coupling rod bearing holes. The axle boxes can then be fitted on the locomotive packed up to the same height. The discs can then be adjusted on the axle boxes so that the coupling rods fit . On an 0-6-0 I would fix the discs for the middle axle in the correct position relative to the frames etc, then adjust the first and third axle discs to fit the coupling rods. The discs can then be used to align each axle box for boring as mentioned before. I think I saw this method in a book by Ivan Law.

Not having a clamp for a faceplate I recently machined my axleboxes thus:- Clock on the mill to locate centre point and centredrill deep enough for a pointed wobbler to locate. Place onto lathe in the 4-jaw with wobbler in the tailstock and a dti measuring the movement on the wobbler. Adjust till the wobbler says you're on the hole.

Once one is done and removed, even if you retighten the same jaws as loosened the next will require some reclocking, but with practice its pretty quick and accurate (so long as you were accurate to begin with).

Yes, second for Dereks advice too – my 4-jaws will not provide repeatability by the "loosen two jaws" method.

This method may be OK for 'near enough' work (if you don't need absolute accuracy) but it won't give you 'spot on' – the work does need re-checking again for truth. This could be down to my 4-Jaws (or it might be me over-tightening) but either way, it didn't give me good results. So I don't use this method now and personally I consider it bad practice.

Regards,

IanT

What about a Keat's angle plate on the faceplate?

If only the clamp plate is moved each time surely the axle-box should be square?

Richard2.

Here's an approach I haven't used but should give a very accurate result.

Drill and ream four oversize blank axle boxes.

One at a time, stick a (relatively small) round bar in the blanks and use bar across the top of the milling vice.

Use this set up with each block in turn to skim the TOP dimension of the boxes.

Now use a square on the top surface as a reference, to reset each box in turn at 90-degrees each way using the same bar and setting the cutter taking a cut at the appropriate height for the sides of the boxes. If set accurately the boxes will all be parallel with the hole central and sizes the same.

Now reset the cutter height and do the bottoms.

Finally groove or step the sides of the boxes as required.

I have found the bar in a hole method to give cuts to a very high level of repeatability from a hole.

This is also a very easy way to mill a round surface concentric with a hole, by taking multiple cuts.

Neil

I've looked up Ivan Laws method of doing this job. It is described in chapter 10 of 'Measuring and Marking Metals' one of the Workshop Practice Series from Tee Pubishing. I'd be interested to hear what people think of this method.