Dumb question on R8 (i think) spindle

I use Brown and Sharpe #7, 9 and (mostly) 11. None have set-screw/key, key-way etc.

For sure there are other collet systems that do.....lemme dig a bit....

-brino
 
Jim F said:
That is what I said before, something is off with that spindle. My R8's sit just under the end of the spindle, without the drawbar installed.
Click to expand...

This what I’ve been saying too.
My hunch is that if the spindle were blued up and a collet inserted, there would only be a circle of blue where the end of the spindle makes contact with the collet.
 
Did you ever use a protractor to measure the angle of the nose? I presume that might be particularly telling.

It is also possible that it is just a poorly cut spindle, but I'd want to see it blued and measured best we can if possible.
 
Is that a pin sticking out at 6:30 just below the draw bar on post #104? It looks like it. Is it above the total length of the R8 collet? You can just drop a rod into the spindle until it rest on the pin and pull it out and compare with your collet length..
 
Post 104 does not have a pic? If you mean post 109 by me then yes, that is the pin. It engages the collet on the straight part (Zone C). Given that his pin is in a similar location I am thinking that this is an R8 with damage preventing the collet from seating.
I like the idea of a rough measurement of the taper with a protractor. Quick and dirty method: you could also take an impression of the lower taper with plasticine clay and check that against a collet. The angle should be 8.5 on each side or 17 deg total.
Robert
 
Last edited:
rwm said:
Post 104 does not have a pic? If you mean post 109 by me then yes, that is the pin. It engages the collet on the straight part (Zone C). Given that his pin is in a similar location I am thinking that this is an R8 with damage preventing the collet from seating.
I like the idea of a rough measurement of the taper with a protractor. Quick and dirty method: you could also take an impression of the lower taper with plasticine clay and check that against a collet. The angle should be 8.5 on each side or 17 deg total.
Robert
Click to expand...
My bad on miscounting posts. I thought you had posted you had removed the set screw which was sheared. Is this the replacement set screw? Does your collet slot engage this pin? Sorry for the primitive questions.

Measuring the taper of both the spindle and your collet is a very good idea!

If you remove the drawbar and insert a rod of the diameter of slightly less than the collet backside diameter (to avoid engaging the pin) how far does it go in compared to the collet length?

Crazy idea, can you make a rubber (or rubber like) impression of the insides? Don't know exactly how to do this, but isn't the issue basically checking all these internal spindle dimensions as compared to a known good R8 collet?
 
Wobbly, I think you’re afflicted with the same malady as me. I was confusing rwm with r-mm until I finally noticed that rwm’s spindle pic didn’t match r-mm’s pics. ;)

General question, does it seem to others that the sheared set screw in r-mm’s spindle is awfully far up in the spindle for an R8 guide pin/screw? I have a bench mill, not a knee mill, but like Jim F, the guide pin/screw isn’t nearly 3-1/2” from the end of the spindle. Mine is more like 1-5/8”. Is it common for the pin to be recessed as far in as r-mm's on, say, a Bridgeport or similar spindle?

Tom
 
My pin is pretty low as well, that one is shockingly high! I'm unsurprised that it is sheered off, it looks like you could engage the drawbar before hitting the pin!
 
ErichKeane said:
My pin is pretty low as well, that one is shockingly high! I'm unsurprised that it is sheered off, it looks like you could engage the drawbar before hitting the pin!
Click to expand...
True! I hadn't even thought of that. Could that be how it got sheared?

Tom
 
You must log in or register to reply here.
Back
Top