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Recommendation needed: Tap, to cut threads in hardwood

2K views 18 replies 10 participants last post by  cazclocker 
#1 ·
Apologies for the obviously newbie post - I'm not a wood worker, I'm primarily a machinist. My task at hand requires me to create female threads in the butt end of a poll cue-stick, so I can thread in a metal threaded insert. Required threads are to be 3/4-10. Because the threaded insert needs to be seated at the bottom of a hole (which I will drill), obviously I'll need a bottoming tap rather than a plug tap or the other types.
My question is, since I'm cutting wood instead of metal, should I purchase a 3-flute tap or a 4-flute tap? Or is there a better way to cut thread in hardwood?
Thanks in advance.
 
#5 ·

I often recommend a couple coats of CA glue on thin or fragile wood constructions. Just let it soak in and dry for an hour, then repeat. Now you have fiber reenforced plastic and it is much stronger than wood. Try it on scrap and see what you think.
I assume you have the male section already and that it's 3/4" x 10tpi.
 
#7 ·
3/4-10 is pretty coarse threads. But I would recommend using a metal threaded insert on the female side. the force of tightening the two pool cue halves together repeatedly will cause the wood threads to wear enough that you can't tighten it properly. Metal to metal is best if you have to connect/disconnect repeatedly.
 
#9 ·
Thanks guys. As guitarphotographer pointed out, 3/4-10 is pretty coarse - only 10 threads per linear inch. Once I have the threads cut into the end of the pool cue, I plan to apply some wood glue to the freshly cut thread and then insert the steel threaded insert and leave it there permanently. I just wondered if a 3-flute tap would work better for wood than a 4-flute tap. Catpower, you mentioned you have used whichever you had on hand... I'm guessing it doesn't matter to much. I appreciate your advice to back out more often than I would with steel, though.

Thanks guys.
 
#12 ·
Probably needs to be able to take the cue apart, hence the fastener.

I too have used whatever tap is on hand and sizes from 10-24 up to 3/4-10. When I do that I tap just like I do in metal except I use my cordless drill on most. When I make fixtures often the easiest way to fasten parts together is to just drill and tap - Maple, Poplar, Beech - that's what I use most often and the screws are able to be tightened fairly tight without stripping the threads. Most of the holes for the smaller sizes are deeper than 1/2", though, so this has to help.
 
#17 ·
No problem, I'll be happy to post a pic here.

Start with a 4 fluted plug tap and then finish with a bottoming tap.
Or if you only have 1 tap then start with a plug and then grind the end on a bench grinder to make it into a bottoming tap.
Starting a bottoming tap by hand tapping and getting it straight to the hole can be very tricky.
That's an excellent point. I once ruined a project by trying to start threading a cast iron piece with a bottoming tap! Duh.... it all seems so obvious now...lol
 
#16 ·
Start with a 4 fluted plug tap and then finish with a bottoming tap.
Or if you only have 1 tap then start with a plug and then grind the end on a bench grinder to make it into a bottoming tap.
Starting a bottoming tap by hand tapping and getting it straight to the hole can be very tricky.
 
#19 ·
Thank you for your recommendation, I appreciate it! I looked, and you are right - but the thread pitch I need has to be 3/4-10, and the woodcutting taps I find online seem to all be 3/4-6 which won't work for me. Because in the end, I have specific threaded inserts I need to use, and they have outside threads of 3/4-10. So for now I'm just going to get machinist's taps - 3/4-10 size threads...a plug tap for starting the threads and a bottoming tap for finishing the threads. Looks like I'll also have to get a 21/32" drill bit to get the whole thing going.
I will be sure to post a couple pictures of my final project.
Thanks guys!
 
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