3/32nd axles

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Winander
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3/32nd axles

Postby Winander » Thu Jan 14, 2021 4:27 pm

I am about to receive wheels made for 3/32nd inch axles. I will be using CSB with High Level horn guides and bearings.

They are all carrying or tender wheels so fortunately no gearboxes will be harmed.

I don't believe there is sufficient metal in 2mm bearings to ream them out to 2.4mm (3/32nds) as the horn guides have a separation of 2.6mm and the effective bearing outside diameter (within the slots) can only be equal to or an interference fit less than this. In addition the axle holes may not be central.

So the choice is to bush the wheels to fit a 2mm axle, or turn down a 1/8 inch axle. I am inclined to the latter. I don't believe the larger horn guides will be intrusive and I have a lathe and, although very inexperienced, I believe I can do it with care and plenty of stock. I only have a three jaw chuck and its on a Sherline lathe. I do have a concern that collets would be preferable, but don't want to go to that expense just yet.

Any guidance, recommendations or other opinions/options will be gratefully received.
Richard Hodgson
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grovenor-2685
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Re: 3/32nd axles

Postby grovenor-2685 » Thu Jan 14, 2021 4:37 pm

Can you not buy 3/32" rod and just cut to length?
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Keith
Grovenor Sidings

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Winander
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Re: 3/32nd axles

Postby Winander » Thu Jan 14, 2021 4:43 pm

Hello Keith,

Ground rod is available, but my concern is fitting bearings. I could bush the rod to fit 1/8 bearings and didn't think of this until you prompted it.

thanks
Richard Hodgson
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Philip Hall
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Re: 3/32nd axles

Postby Philip Hall » Thu Jan 14, 2021 6:07 pm

A Sherline chuck is usually very accurate (about 1 - 1.25 thou run-out) but you will still struggle to turn down an axle concentrically without a collet chuck. An alternative is to make your own collet for that one application by drilling a length of brass rod 3/32”, marking the jaws of the three jaw on the brass and then slitting the ‘tube’ with a hacksaw. That’s what I have done on my old Unimat which has a Sherline chuck.

The other way is, as you say, to make up some conversion bushes of whatever size you prefer which should be quite easy to do on the Sherline. That’s what I would go with.

Philip

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Will L
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Re: 3/32nd axles

Postby Will L » Thu Jan 14, 2021 6:10 pm

The Standard Highlevel Hornblock comes drilled either 2 mm, 1/8" or 3mm. You should have no problem reaming out a 2mm bearing block there would be plenty of meat left.

Jeremy Suter
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Re: 3/32nd axles

Postby Jeremy Suter » Thu Jan 14, 2021 7:31 pm

Hi Richard
You mention you have a lathe and assuming it has a jacobs chuck for the tail stock. Would it not be the simplest to make completely new 3/32 bearings to suit
Machining the ends of 1/8 axles to 3/32. I would not recommend using a 3, 4 or 6 jaw self centring chuck. All self centring means is all the jaws come in at the same time and I have never found one that actually will centre the work correctly without being machined by the owner.
So for work like re-cutting the ends of the axles You really need a collet they are expensive but well worth the cost in the end.
As Philip says its not hard to make your own collet, but you must remember exactly how it was fitted in the chuck so when you remove it, you can replace it in the correct position, not doing so could double any error you had before if its replaced the wrong way round.
Making your own collet should be done with a smaller drill and enlarged to the right diameter with a boring bar but the size in this case is against doing that

Or you could ask me to do them for you.
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Winander
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Re: 3/32nd axles

Postby Winander » Thu Jan 14, 2021 9:17 pm

Will L wrote:The Standard Highlevel Hornblock comes drilled either 2 mm, 1/8" or 3mm. You should have no problem reaming out a 2mm bearing block there would be plenty of meat left.


Your comment led me to High Levels site and a discovery that the standard block does come in the three variants as you describe. I had assumed. Never assume.

Thanks to Keith, Philip, Jeremy and Will for the educating responses. I have learned a valuable lesson regarding chucks and a reminder of how to DIY colletts.
Richard Hodgson
Organiser Scalefour Virtual Group. Our meeting invitation is here.


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