Measure internal taper

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goldstar31

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Thank you but I am in no position to disagree.
I have one lathe with MT No 2's and another with a No3 and a No2. The Mill/dri;; is No3 and I was sufficiently prudent to ensure that ALLL my workshop has either Myford tooling or the ability to be adapted. So problems either do not exit or are very minimal.
Nevertheless my best wishes in overcoming what seem to be difficulties

Norman
 

comstock-friend

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How would I accurately measure an internal taper? This came up as I was trying to determine the taper inside the headstock on my South Bend lathe. It is either #5 or a SB special taper. I was thinking about making an adaptor to fit 5C collets instead of the external holder I now have.
Here is a (later models) South Bend tooling chart. What model South Bend lathe do you have?
 

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Gordon

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Well I finally got the answer. I took a piece of drill rod and jammed it in the bore with a tapered piece of wood to hold it tight against the tapered side of the spindle. I then took my dial indicator and put it against the rod at 12"+ away from the spindle and moved the carriage 12" and the indicator showed .301 so double that is .602 which is the proprietary SB taper. I knew that it had to be .6024 if it matched the #3 MT angle or .6315 if it matched the #5 MT. Several sources said that it matched the #3 taper but bigger diameter which is true. Crude but it worked.

Gordon
 
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