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Make my own tap? Or shorten hardware?

Jamie Straw

Jamie Straw

Joined
May 28, 2015
Messages
1,607
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Location
Bainbridge Island, WA
Pfui! I bought hardware to make coffee scoops. Pleased to find the threads are the same as on my stopper mandrel, thinking I can tap with the stopper mandrel. Fine, except the threaded part of the coffee scoop is almost twice as long as on the stoppers! Seriously? So, not wanting to pay or wait for a tap to come from Craft Supplies, seems I could either shorten the threaded stem, or make my own tap out of a bolt, which is purely an idea, have never done it before and don't really know how. Suggestions? Picture below is how Ruth's tap is made.Stopper Tap.jpg
 
Well, for a coffee scoop, there is not much stress, so I don't believe shortening the bolt would be an issue. But your local Ace Hardware would have a 3/8th X 16 tap...I would have to buy the tap...more tools...
 
I've tried DIY from a bolt and it really doesn't clear the waste very well. I agree with Clifton, should be easy to find one at the local hardware store.
 
Jamie, the bolt won't work well. The tap is slightly larger and has slightly deeper and sharper threads because there needs to be thread clearance or else there would be binding. You might find a cheap imported tap at an auto parts store. Look for a bottoming tap or get a regular tap and grind away part of the leading end.
 
Well, I needed to order a new spur drive, so I just went ahead and ordered the tap from CS, added on one other goodie for Christmas presents (tops-drawing do-dahs for the kids). Glad I didn't try to make my own.
 
A bottoming tap is not very tapered, it's pretty blunt. Its intent is to tap as far into a blind hole as possible.

In metal (not wood), only the first few threads (about 4) engaged in the joint carry all the load. More threads don't hold any tighter. (That's a bit of an oversimplification, but let's just go with that).

Depending on the wood, the scoop's threaded fastener may be able to cut its way through un-tapped wood. Wood screws, for example, are intended to cut their own way into wood, or into a pre-drilled hole.

We use sheet metal screws (self-tapping sheet metal screws) to screw bowl blanks to faceplates.
 
Hy Tran said:
A bottoming tap is not very tapered, it's pretty blunt. Its intent is to tap as far into a blind hole as possible.

In metal (not wood), only the first few threads (about 4) engaged in the joint carry all the load. More threads don't hold any tighter. (That's a bit of an oversimplification, but let's just go with that).

Depending on the wood, the scoop's threaded fastener may be able to cut its way through un-tapped wood. Wood screws, for example, are intended to cut their own way into wood, or into a pre-drilled hole.

We use sheet metal screws (self-tapping sheet metal screws) to screw bowl blanks to faceplates.
Click to expand...
Craft Supplies sells a tap for their kits that have threaded bases, I doubt the scoop's fastener could tap. I'm cynical enough to think they made the threads long so that they could sell mandrels.🙄 The only kit I've bought so far that I though might be a candidate for such a long thread insert is the Artisan pizza cutter -- it's heavy and big, and needs to work hard.

I'm going to venture forth, cut off the threads of the coffee scoop. I'd much rather tap with the stopper mandrel, using my lathe, than with a tap. Thanks!
 
Well contrary to the crowd I needed a 3/4 tap to make a soft touch for the live center and a bolt worked great . I filed in 4 notches and make sure that the back side which is cutting is straight up and not angled. File these pretty deep. When threading even with a bought tap back out at least every turn. I also did this with a nut to hold chuch in live center.
 
I'm with Gerald I've made quite a few homemade taps over the years. Grind or file 4 slots in the sides similar to what a real tap looks like. Then grind down the first 3 or 4 leading threads a little so it's easy to start in the hole. Sure it doesn't cut as clean as a real tap but when you need one quick it sure is easy. I made a 1/4x20 tap that was 4" long to tap into a deep hole. Just used a long carriage bolt. It's in my tap drawer for future needs now.
 
Jamie if you had a mill and know how to use it, you could make these taps quite easily, however if you have a good drill press you can get there also.

Take the treaded bold and spin a nut on it till it’s even with the top of the rod, drizzle a drop of CA in and let it harden up.

Clamp the nut in the drill press vice and move it over till you have the edge of the rod right under the drill, (drill size depends on size of the tap you are making) then carefully drill right through the nut, rotate the nut and bolt and repeat, a small tap needs 2 or 3 holes drilled, larger and you go for 4.

Remove the nut from the bold and grind file some relief on your tap also taper the first bit of the tap to get it started easier.
Make your own tap.jpg
File relief on tap.jpg

I made some scoops for coffee, spices etc, no treading required, maybe not as nice as yours, but they do work and sell.
scoop sets.jpg
 
Pete Blair said:
Jamie, I'm not sure why you need to shorten the threads but it would seem to me if you added a small spacer you could make the length of the thread any dimension you wish.
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I need to make the threads in the wood longer than my tapping-mandrel will reach. I went ahead and ordered the Crafts Supply mandrel, since I needed something else from them anyway. Thx.
 
Leo Van Der Loo said:
Jamie if you had a mill and know how to use it, you could make these taps quite easily, however if you have a good drill press you can get there also.

Take the treaded bold and spin a nut on it till it’s even with the top of the rod, drizzle a drop of CA in and let it harden up.

Clamp the nut in the drill press vice and move it over till you have the edge of the rod right under the drill, (drill size depends on size of the tap you are making) then carefully drill right through the nut, rotate the nut and bolt and repeat, a small tap needs 2 or 3 holes drilled, larger and you go for 4.

Remove the nut from the bold and grind file some relief on your tap also taper the first bit of the tap to get it started easier.
View attachment 21272
View attachment 21273

I made some scoops for coffee, spices etc, no treading required, maybe not as nice as yours, but they do work and sell.
View attachment 21274
Click to expand...
Thanks, Leo, next time I might try that. I do plan to make some all-wood scoops next year, but for Christmas I'm doing the chrome kits for various kitchen items (and SS stoppers from Ruth Niles, of course😎)
 
Well, the tap arrived. Doesn't work near as well as Ruth`s, not sure why. Her's has the one groove, their's has 4. Probably made for metal? Have only used it on maple and dogwood, chewed up the wood pretty bad. What finally worked, though, was to use Ruth's to start the hole, about 1/2", then go back in with the Craft Supply tap to finish it. Ruth's tap peels the wood, this new one from CS sorta chews it. Will only make these long threaded holes for tthe pizza cutters, trim the hardware for everything else.
 
Threading wood isn't easy.. Most domestic hardwoods aren't suitable for threading. I can't remember which ones are suitable. Some dense tropical hardwoods are easier to thread. From watching demos on threading,first drill an oversized hole because the hole size given in charts is for metal. Wax helps to reduce friction. My guess is that the four flute tap doesn't provide enough support while cutting the wood. I have used a regular tap for cutting 3/4 X 16 threads in maple to make special jam chucks for my live centers. I used hard maple and fortified the wood with thin CA glue. After a lot of failures I made the hole considerably oversized and the results were good enough for the intended use. I seem to recall that the best one was where I just hand twisted the piece of wood onto the nose of the live center.

I bought the Sorby tools for hand chasing threads about a year ago, but still,haven't worked up the nerve to actually use them. 😱
 
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