Need Tap for new 3/8 x 10 pins

[rwomel]

Hello All
Well, I didn't get out and go to the Super Expo this year. So I suspect an answer will take some time for this easy question. I tried "searching" for the answer, and some reason the search feature is not working.

I need to build a shaft for a customer, and attached is the older style 3/8 x 10 joint pin, and the newer style with flat valleys. I am asking for a sorce for a tap for the NEWER style pin. I have looked on Atlas, and Prathers. If they are there I didn't see them.

Also, what pilot hole size in inches should I drill? I don't think it is a big as the older style, right?
Thanks in advance

(Picture is from DZ Cues, Thanks )

RWOMEL
South Texas

 

[nbll01]

If I'm not mistaken those are referred to as acme threads. At least thats what I've heard them called...........Dave

 

[Michael Webb]

The new is not acme, just flat bottom, I have seen two, one is .298 and the other is .305 I do not who is using which.

 

[dzcues]

Hello All
I need to build a shaft for a customer, and attached is the older style 3/8 x 10 joint pin, and the newer style with flat valleys. I am asking for a sorce for a tap for the NEWER style pin.
Also, what pilot hole size in inches should I drill? I don't think it is a big as the older style, right?
(Picture is from DZ Cues, Thanks )
RWOMEL
South Texas

Before you build this shaft you need to have one thing absolutely clear: does his cue have the old thread or the new? If it's the new thread, are you sure it's 3/8-10 flatbottom or 3/8-11 flatbottom (which looks very similar but isn't the same pitch nor is it really 3/8 diameter).

But to answer your question: A standard 3/8-10 tap will work with this thread. I ground a .307 diameter pilot on the tap to follow the .307 hole - which is bored - not drilled. Or...lacking a tap with a pilot, you can chase the threads with a thread mill. Or...as a last resort, you can just try tapping the bored hole & hope it follows accurately. If it doesn't, you'll be forced to open up the bored hole, which ends up defeating the purpose of the flatbottomed pin.

Best bet is to drill, bore & tap a test piece & see how it fits the customer's cue before whittling on a nice shaft blank.

 

[Craig Fales]

You don't need a new tap for the flat bottomed thread pattern...I would think an 11/64th drill bit should do it and tap away with a standard 3/8 x 10 tap...

 

[iusedtoberich]

I haven't used this screw...

But if it is indeed a 3/8-10 thread with a 60 degree included thread angle (as opposed to an ACME screw which is not 60 degrees), that simply has a shallower than normal thread depth...

You could drill/bore then tap the shaft with your normal 3/8-10 tapping procedure. Once that is done, and with the shaft still in your holding setup, open up the hole using a boring bar to the minor diameter of the actual screw your customer has on his butt. Judging by the picture, you should be able to easily measure the minor diameter of the screw with a pair of dial calipers. It looks like there is enough room to fit them in between the threads.

 

[dzcues]

You don't need a new tap for the flat bottomed thread pattern...I would think an 11/64th drill bit should do it and tap away with a standard 3/8 x 10 tap...

I don't mean to sound contentious but if we are still talking about the pin shown in the picture (my picture, BTW), I can state with authority that:

A. The flatbottomed pin will NOT fit if the hole is smaller than .307 dia.

B. The flatbottomed pin will get increasingly sloppy as the hole size increases beyond the .308 design limit.

I'm sure you meant 11/32 drill in your post but you will end up with a sloppy fit if the hole is that large. The whole point of the flatbottomed thread is for the pin to locate on the minor diameter of the pin - which happens to be about .307 diameter.