1968FJ40
Aluminum
- Joined
- Jun 3, 2006
- Location
- Arlington Washington
Recently I was given a job that required a 7" deep by 1.250" bore. Fearing that my little 1/2" Emco boring head wouldn't be up to the task I asked a friend if he had something bigger that he could lend. Happily he had a bigger boring head. Since the thing had been in his possession for many years, and he had never used it he just gave it to me! WOW! It is a Wohlhaupter UPA 5-s6 with (he said) an R-8 shank.....perfect for my Bridgeport. I thought it a little strange that the spindle was about 3/4" shorter than my R-8 collets and the draw bar threads were 5/8-11 whereas my collets are 7/16-20. Somebody had previously adapted the thread by threading in a piece of brass or bronze that had the 7/16 thread cut into it. I stuck it into the Bridgeport spindle, set up a bar, and started to cut. I COULD NOT GET A DECENT FINISH TO SAVE MY LIFE! Tried EVERYTHING. Finally, in disgust, pulled the boring head out, made an adapter with a back brace so I could stick a 5/8 bar into my old 1/2" Emco head and completed the job.
Now, I am back looking at the Wohlhaupter head trying to figure out what went wrong. It looks to me like the taper at the nose is slightly different than my R-8s. So I am figuring that this is definitely NOT an R-8. But what is it then? I am not familiar with any collets that are this deceptively close to an R-8? anybody got any answers????
Kirk
Now, I am back looking at the Wohlhaupter head trying to figure out what went wrong. It looks to me like the taper at the nose is slightly different than my R-8s. So I am figuring that this is definitely NOT an R-8. But what is it then? I am not familiar with any collets that are this deceptively close to an R-8? anybody got any answers????
Kirk