Repost (again) Photos in dropbox

On 20 Mar 2005 17:47:15 -0800, the inscrutable "Pete K." spake:

Could you explain the 3/4 x 4ish threadmaking for me?

That's a nice little fitting. Did you also make the SS thumbscrews?

--- After they make styrofoam, what do they ship it in? --Steven Wright

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I bought the thumbscrews from McMaster-Carr. I'm going to need this thing Friday (spring break in Texas).

I set up to thread for the mop handle (3/4" 5tpi, sort of acme thread form) by drilling then boring deep enough for the threads plus the end of the threading boring bar. I used one of the solid carbide insert boring bars for the plain boring (Photo 01). Pretty neat tool.

I then ground a bit to fit the 5tpi acme specs, using an acme thread gage. Since there was no way I wanted to thread into a blind hole at

5tpi, even in back gear, I set the threading bar up on the back side of the hole (like in Photo 02), and ran the lathe in reverse. This causes the threading to proceed from left to right, or out of the hole, for a right handed thread.

Otherwise, the only thing a little different was I had to swap from the 24 tooth to 48 tooth stud gear, which is required on my 11"x24" Delta to cut 4 through 7 tpi threads. When I was done, the mop handle wouldn't fit because of the rounded thread form. I then opened the minor diameter a little and ground a bit to break the edges of the thread. I had to pick up the thread because I had removed the boring bar, but I just set the threading dial, then moved the bar in and out until it was centered in the thread, then tightened the boring bar clamp screws.

Threading is fun. The trick of running in reverse for internal threads is a good one. I think I read it here.

Regards,

Pete Keillor

I bought the thumbscrews from McMaster-Carr. I'm going to need this thing Friday (spring break in Texas).

I set up to thread for the mop handle (3/4" 5tpi, sort of acme thread form) by drilling then boring deep enough for the threads plus the end of the threading boring bar. I used one of the solid carbide insert boring bars for the plain boring (Photo 01). Pretty neat tool.

I then ground a bit to fit the 5tpi acme specs, using an acme thread gage. Since there was no way I wanted to thread into a blind hole at

5tpi, even in back gear, I set the threading bar up on the back side of the hole (like in Photo 02), and ran the lathe in reverse. This causes the threading to proceed from left to right, or out of the hole, for a right handed thread.

Otherwise, the only thing a little different was I had to swap from the

24 tooth to 48 tooth stud gear, which is required on my 11"x24" Delta to cut 4 through 7 tpi threads. When I was done, the mop handle wouldn't fit because of the rounded thread form. I then opened the minor diameter a little and ground a bit to break the edges of the thread. I had to pick up the thread because I had removed the boring bar, but I just set the threading dial, then moved the bar in and out until it was centered in the thread, then tightened the boring bar clamp screws.

Threading is fun. The trick of running in reverse for internal threads is a good one. I think I read it here.

Regards,

Pete Keillor