tap and dies

[johnmostyn]

Hi all,
Im pretty new to home machining, bought an optimum 2506v lathe 2nd hand that came with a lot of extras, as the guy we bought it from was upgrading his lathe. the compound slide was taken off and had his tool post on the cross slide. anyway, I have finally gotten the compound back on after chasing up a few bits and pieces that was missing. The tool post is a quick change with 2 slots and the stud on the quick change is a 9/16 UNF. Is 9/16 UNF, 9/16-12 or 9/16 - 18?
I have to run a die over the threads to clean them up and I don't know which die to use? Neither die will run onto the stud with ease.
thanks for your help
cheers
John and Tina

[Bill Shields]

Sure it is 9/16 and not 15mm?

[johnmostyn]

Hi Bill, yes, it is 9/16, had a guy at a faster shop tell me its 9/16 UNF

[Bill Shields]

Well if the die does not fit.. then something does not agree

Unf is 18

Unef is 24

Get yourself a thread gauge and measure it

Did the guy @ fastener shop measure with anything other than eyeball?

If you put a micrometer on the threads. What is the od?

Did fastener guy have a known nut to fit?

[Bill Shields]

If you have the QCTP shown in the optimum catalog page . I would be very shocked if the hardware is not metric

[Bill Shields]

15mm x 1.5 thread is .059" pitch

Very close in pitch to 18 tpi.. but not close enough to run a die onto..

[johnmostyn]

Hi Bill, I put a thread gauge over it and SAE 18 was the fit. From what I read SAE and UNF are the same. So my UNF 9/16-18 should do the trick. BTW its a aftermarket QCTP as well. thank you

[Bill Shields]

well there you go....solution to conundrum!