Help with tap and die sizes please

I have started turning threads on wood using 18, 20 and 24tpi woodturning thread chasers. For the internal threads I would like to be able to put threads into a drilled hole to fit a 6mm threaded spigot.

I'm afraid I have no knowledge of metalwork, could anyone please tell me the tap (or is it die) size that I would need to match each of the

18, 20 and 24tpi chasers?

Many thanks for your help

Paul

Reply to
Paul Loseby
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Wow, 24tpi on wood? Must be ironwood...

That sounds like a pretty tiny spigot. Are you making doll house sized stuff, or perhaps you've mistaken the units of measure you're using? If it really is that small I'd be inclined to look at adhesives for fastening it into the hole.

Woodcraft Supply sells lots of sizes of taps and dies (which they refer to as "threadboxes") for wood, but 1/2" diameter is the smallest they list. Take a look at:

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Good luck, let us know how you make out.

Jeff

-- Jeff Wisnia (W1BSV + Brass Rat '57 EE)

"If you can keep smiling when things go wrong, you've thought of someone to place the blame on."

Reply to
Jeff Wisnia

Many thanks Jeff and I will have a look at that site. I've been making some miniature puzzles where the spigot needs to screw in and out of the hole. I can put threads on by hand on the outside but my thread chasers won't go into the hole because of their size, hence using a tap.

Most woods CAN be threaded but unless it is a really hard wood such as African Blackwood, Cocobola, Lignum Vitae etc you tend to get a lot of crumbling of the threads. I've actually only been turning for about

12 months but I have managed to learn to turn threads and you tend to be able to make things a little out of the ordinary. So far I've only been doing screw top boxes but I just wanted to go that bit further.

Very many thanks again for your help - I do appreciate it

Paul

Reply to
Paul Loseby

You might just try using a metalworking tap, say 1/4-20 thread, which is pretty close to the 6mm diameter you mentioned, and then adjust your threading of the male part to suit. They are available in a variety of styles, including ones with tapered tips for starting threads and "bottoming" taps with blunt ends used for finishing threads to the bottom of holes which don't go all the way through the part. You could probably get away with cheap hardware store taps for wood, and could make your own bottoming tap if you need one by grinding off the tip of a tapered tap.

Or, you could consider installing a female threaded insert made made for just this sort of stuff. Here's a link to one place that sells them, though I'm sure you could do better on price if you Google around for them, I know they're made as die castings too:

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I'm sort of curious about what tools you are using to make the male threads. You said in your OP that you were "turning" the threads, which implies that the part you were threading was rotating in a lathe. Was that just a slip of the keyboard, and are you really cutting them by turning a chaser by hand onto a round piece of wood to cut a thread?

Jeff

Reply to
Jeff Wisnia

Hi Jeff - yes it is chasing the threads by hand using 'chisels' with a thread cut into the end. It has taken me about 12 months to master it and I need to slow the lathe down to about 200rpm. It's then a case of introducing the tool in a circular motion by hand until it gets a positive thread and then extending it and making sure that you lift the tool out before reaching the end otherwise it ruins the threads that you have made.

If you want to have a look at

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gives you an idea of what is involved. Actually it gives you quite a thrill when you get one right first time.

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shows some of my boxes that I've made with screw threads so far but like I say I want to do some turning of puzzles etc that involve smaller screw threads out of wood

Again many thanks for your help

Paul

close to the 6mm diameter you mentioned, and

variety of styles, including ones with tapered

finishing threads to the bottom of holes which don't go

store taps for wood, and could make your own

this sort of stuff. Here's a link to one place

around for them, I know they're made as die

You said in your OP that you were "turning" the

lathe. Was that just a slip of the keyboard, and are

to cut a thread?

Reply to
Paul Loseby

formatting link
it gives you an idea of what is involved. Actually it gives you quite

Wowza! Thanks for teaching me one more toolish thing I never knew before. I can see how it can take a while to get the right "touch" for doing that sort of stuff.

And, I was sort of saddened by the note at the end of that page:

Bill Jones is the last of a family who have been ivory and hardwood turners for 150 years. Bill has over sixty years of experience as a professional and now spends his time passing on his unique skills to a new generationi, in the hopes that some will survive.

I guess nothing is forever, is it? (Save for death and taxes plus whatever other humorous and ribald things the members of this august body may choose to add.)

Jeff

pretty close to the 6mm diameter you mentioned, and

variety of styles, including ones with tapered

finishing threads to the bottom of holes which don't go

store taps for wood, and could make your own

this sort of stuff. Here's a link to one place

around for them, I know they're made as die

You said in your OP that you were "turning" the

lathe. Was that just a slip of the keyboard, and are

wood to cut a thread?

Reply to
Jeff Wisnia

On Thu, 06 Nov 2003 17:35:25 -0500, Jeff Wisnia brought forth from the murky depths:

Do those trolls tug much on the line, Jeff, or can they use lightweight monofilament line on freshwater reels for you guys who bite? ;)

-- Friends Don't Let Friends Eat Turkey and Drive --

Reply to
Larry Jaques

Uh, care to restate that one Larry?

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Jeff...

-- Jeff Wisnia (W1BSV + Brass Rat '57 EE)

"If you can keep smiling when things go wrong, you've thought of someone to place the blame on."

Reply to
Jeff Wisnia

On Fri, 07 Nov 2003 16:14:55 -0500, Jeff Wisnia brought forth from the murky depths:

Sigh...OK, but while it might be "real", those fine threads on wood are ridiculously frail. Pass.

-- Friends Don't Let Friends Eat Turkey and Drive --

Reply to
Larry Jaques

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