Need Help!- Identify this spindle nose?

[serriadh]

I'm trying to identify this spindle fitting, which is on a Denford Orac lathe. The Denford forums and other Orac-related groups don't have any information on it at all.

Its a short taper, with the chuck backplate fastened into place with three studs.

Quick and dirty dimensions:

• OD: 78.4mm
• BCD: 59.2mm
• Large diameter of taper: 41.1mm
• Small diameter of taper: 39.7mm
• Depth of taper: 7mm
• Mounting studs: M8
• Spindle taper: MT3
• Spindle bore: 20mm

I've included a couple of pics with my calipers for scale. The measurements, especially of the taper itself, are clearly not accurate enough to get any idea of the taper angle which I'd expect to be more like the 7 degrees, 7', 30" angle of US/BS/ISO short tapers if I'd measured it correctly.

My best guess is that its an old US or possibly even BS/ISO A2 short taper, but it is too small to match any of the dimensions I've been able to find anywhere online. Possibly it is a 2"-size, and all the spec sheets start at 3"... I've heard a few people talk about D1-2 spindles for which I've found no published information, so perhaps other tapers existed in the same size.

There are a couple of official standards documents floating around (BS4442 Part 1 and I.S.O. R702 Part 1) but they're not cheap (£50-80) and may not even include this taper so I'd rather not throw away that money and hope for the best.

Any bright ideas? I guess I might have to try measuring it up more accurately and trying to machine my own backplate, but I'm not yet confident in my abilities to make an accurate backplate, even with CNC!

[Fastest1]

I believe the 3 hole specifies A2. I have a similar looking spindle. I called Kalamazoo Industries @ 888-727-4703 ask for Jerry. He is very knowledgeable in regards to spindles, chucks and adapters. About a 3 week turnaround on mine. They are making an adapter from an A2-4 to a Buck 4" Adjustru chuck. Seems like it was right about 200 usd.

[M250cnc]

Check this page out, might help

http://www.lathes.co.uk/latheparts/page11.html

Phil

[serriadh]

Originally Posted by M250cnc Check this page out, might help http://www.lathes.co.uk/latheparts/page11.html Phil

Yeah, that was my first port of call when I started investigating. The OD of the spindle face is too small for any of those listed there, and anything smaller than a 3" nose size is so uncommon that the dimensions aren't easily available anywhere.

Originally Posted by Fastest1 I believe the 3 hole specifies A2. I have a similar looking spindle. I called Kalamazoo Industries @ 888-727-4703 ask for Jerry. He is very knowledgeable in regards to spindles, chucks and adapters. About a 3 week turnaround on mine. They are making an adapter from an A2-4 to a Buck 4" Adjustru chuck. Seems like it was right about 200 usd.

Bit more inconvenient for me, being in the UK ;-) Especially given that postage of a slab of iron over the atlantic might end up being an extra 50% on top of the machining.

There's bound to be some equivalents this side of the pond though, and its good to have a second opinion about the A2 spec. I know the lathes.co.uk guy does sell a bunch of odd backplates, so he's probably a good person to ask next.

Cheers!

[Fastest1]

Email Jerry with the info you put here and his answer possibly will be free! Then you decide who you want to do the work.
Here is their website. http://www.kalamazoochuck.com/