Wooden Thread Tap

[Mike Olson]

I'm in the process of planning my new bench and something I have always wanted is the large 2" - 3" wooden screw to thread into the bench for the vice's.

Turns out I can't find anything for over 1-1/2". Also, I have read that the current ones are not the proper threading for wood.

Does anyone have any ideas or measurements for building your own tap & die. I know there are a few for the wooden thread box but I'm more interested in how to build a tap for an impressive 3" wooden screw.

I'm thinking a wooden dowel with two teeth secured into them at just the right angle but not sure the angle/spacing/depth or even how to properly secure them for the massive torque I'm sure they will see. Once I have the tap built, the thread box should be the easy part.

Thinking more, maybe a single piece of flat tool steel with a tooth ground on each end offset just right and then secured inside a steel bar and tipped with a wooden plug to keep everything aligned.. hmmm

[george wilson]

We had a 2" cast iron German one at work. There is a German catalog put out by Dick. The 2" taps and dies in it are about $2000.00(were a few years ago).

You need to have 3 threads per inch for authentic wood threads 2" dia..

While I was toolmaker,we made and renewed all the wooden vises in Williamsburg with it. The hard part was getting good 4" thick hard maple.

[Johnny Kleso]

Mike,
I was going to say how about buying a steel nut but I just checked prices at MSC for a 2"-4 it's $66 for a 2 1/2"-4 it's $112 and if you want it in SS its only $818 hehehe

I should have opened a business making 2 1/2" Acme Nuts

ENCO has steel threaded shaft and nuts if you can pin a wooden head to the shaft..

1 1/4" is about $60
1 1/2" is about $100
For a 3' Long Shaft and Nut

You could trap the nut in between two aluminum plates morticed into the leg

[Pam Niedermayer]

Roy Underhill shows how to make a big wood screw in one of the Woodwright's Shop episodes, I think season 2700, but not sure.

Pam

http://www.pbs.org/woodwrightsshop/schedule/video.html

[Brian Millspaw]

I was having the same problem about 10 years ago when I built my bench. I had been working in a carving factory on some old hammecher & schlemmer benches with wood screw vises that I wanted to copy. They had 2.25" dia. screws with 2 tpi. I knew how to make the threadbox, but it took me a whlile to figure out how to make the tap. Basically I made a wooden tap and inserted metal blades. There are pictures in an old post here http://www.sawmillcreek.org/showthread.php?p=1152692

I recently made a tap blank for trevor walsh on this forum. He was thinking the same as you . I can make vise screws, nuts or a tap blank. PM me if interested

Here is a picture of the tap blank I made for trevor, and a picture of my tap underneath his, showing the blades.

-Brian Millspaw

[Adam Cherubini]

I advise against making your own large screws and nuts. There are several folks making these for reasonable prices like this company:

http://www.bigwoodvise.com/

no affliation, blah blah blah

Making screws is a good thing to shop out. Good screws can last several life times.

You can find antique tap and die sets. I have a 2-1/2" set. I think it's 3 or 4 threads. It is seriously hard work to make working screws and nuts. The nuts are particulalry hard to make. The screws require very careful turning prior to cutting the threads.

I say buy them.

Adam

[David Weaver]

If you want to make a lot of them, I think the example george gave is a very good one (setting up a router to cut the threads on the rod). It seems like you could make one threaded set with a collet on the end and use that to turn and pull a dowel past a jigged router.

If it's just a couple, I agree with Adam. Let someone else figure out how to do them, and buy them from the person who figures out how to do them well and offer them for a reasonable price. It's hard enough to cut them by hand on an improperly made smaller import thread box.

[David Weaver]

Here is a picture of the tap blank I made for trevor, and a picture of my tap underneath his, showing the blades.

-Brian Millspaw

Those are really nice!

[Mike Olson]

BigWoodVise.com is no longer accepting orders :(

I would like to figure out how to do this anyway.

Brian what you posted is VERY close to what I was thinking about. only issue is, what comes first the tap or the box? how do you put the thread on the box to feed properly without the tap. how do you make the threads for the tap without having the box. :confused:

[David Weaver]

BigWoodVise.com is no longer accepting orders :(

I would like to figure out how to do this anyway.

Brian what you posted is VERY close to what I was thinking about. only issue is, what comes first the tap or the box? how do you put the thread on the box to feed properly without the tap. how do you make the threads for the tap without having the box. :confused:

buy a short length of 3 tpi steel rod with a nut. That's probably a lot easier to do than making one.

If you're a real glutton for punishment, and you don't have a metal lathe, you could probably make a card paper template cut on an angle, mark a dowel two or three times per inch around its circumference and then mark two or four lines along the length of the dowel. Wrap the cardstock around a dowel to mark the threads with the cardstock moving to the next marked circumference each time it goes around the dowel, and then cut the grooves square with a handsaw and chip them out with a very narrow chisel or gouge. I can't imagine doing that - it would take hours, but it could be done. Then once you make your first "good" threads, replace them in your "feeder" with the good ones.

Jameel has a very good example of something similar on his blog for a totally different purpose, but the layout would be similar.

[george wilson]

Do go find the Roy Underhill program that shows how to make the tap and box. Once you have the box,you can thread the rod. 3 threads per inch is plenty. 2 threads is o.k.,except that the root diameter of the threads is making your vise thread weaker. It is making the vise thread easier to twist off or accidentally crack. Look how small the root dia. becomes with 2 t.p.i..

The wooden vise will most likely last you a long time,but we replaced the vise threads in the Anthony Hay cabinet shop in Williamsburg at least 3 times over the years (1986-2007) that I was toolmaker,but they were in daily hard use.

Generally,you need only 1 tool steel tooth sticking up out of your tap,and it is advanced a little more each time through the box you are tapping. The ones Brian made look nice,too,though.

[Andrae Covington]

Here's the Woodwright's Shop episode from 2007 about making a screw box.

Screw Box for Wooden Threads (http://www.pbs.org/woodwrightsshop/video/2700/2704.html)

His example looks like about 1" diameter, and he used a commercial metal tap to cut threads into the screw box, so that part may throw you a curveball.

There was an episode in an earlier season, before they started putting them on the web (:(), where he had an antique screw box for about 2" diameter, and he made a wooden tap to match. It was quite a contraption! But the central part of it was similar to what Brian Millspaw made above. By the way that larger screw box had two cutters, one set shallow for the initial cut.

If you have (or your library has) his third book, The Woodwright's Workbook, chapter 3 is about screwboxes and taps, both small and large. There are numerous b&w photos and text description. Also included are a couple photos of the ridiculously large cider press screw that George Wilson made.

Also in the appendix of his most recent book The Woodwright's Guide, there are two plates and his loose translation of the related text from Roubo's L'Art du Menuisier about screw boxes and taps. I think the earlier book is more informative, however; though I have not actually tried to make them.

The screws on my workbench vises are from BigWoodVise. Another source is Lake Erie Toolworks.

[george wilson]

The cider screw WAS ridiculously large.:) But it wasn't a ridiculously easy task making it!!

It was a direct copy of an original in Somerset England. 12" dia. 6 threads per FOOT. The bulbous part was 16" in dia.,with 2 5" holes bored through at 90 º to each other to put pry bars into.

Since the large size threads did not offer a very high "gear ratio" for crushing up apples,they used a smaller "sampson" winch to pull on the beams inserted into the bulb of the larger screw. For some reason,I was unable to convince my stupid boss,Earl Soles,who WANTED this press made,that they used a smaller winch to tighten it. Eventually,I found pictures of them using the sampson. By then,I'd just decided to hell with it. Less work for me.

Even better that I didn't build the Sampson,because they are thinking of giving the press and apple grinder to Mt. Vernon,which is a huge mistake. The making of cider was very essential in the 18th.C. It WAS their soft(or hard) drink. Near Williamsburg,at Carter's Grove plantation,I was told they grew 29 kinds of cider apples in the 18th.C..

They seem to find plenty of money for their other building interests,but never could manage to house the cider press. Thus,an essential,authentic industry is lost to the museum,and they will never find anyone else to make another press for them. Visitors would love to see the HUGE press and apple grinder. I mean,it really is impressive.

[Pam Niedermayer]

For what it's worth, after digesting all the effort it would take to make a large wooden screw and nut, including studying a Woodwright's video (2406 Wooden Thread Cutter, see Wikipedia for a complete list of episodes) and that book on it, and what it would take to buy tools to make it reasonably good (they only make sense if you're going into production) and what it costs to buy a screw and nut already made (sorry, Adam, but $145+ is not cheap for that many of us), I decided that if I were to buy I'd buy a metal screw. I'm still interested in making some big wooden screws, but this is on a very back burner.

Making the screw is really pretty simple, once you work your way through handedness and the like; and all you need is a saw, veiner or other chisel, paper, and a lathe to turn the screw blank assuming you can't buy a good enough dowel. Roy has a show doing this. But the thread box is more difficult.

This must be a journey we all take.

Pam

[george wilson]

I do not advise trying to use a dowel. Gluing it into the handle will probably soon fail from twisting stresses. Also,are there any 2" dia. dowels?

Since I don't use dowels,I'm not familiar with what's available.

[David Weaver]

You can get dowels up to baseball bat blank size. Past 1 1/2 inches, they start to get expensive fast, though, and I don't know if the ones that aren't baseball bats are easy to find in a specific hardwood. Even at 1 1/2 inches, you get birch or maple from woodcraft, though there is a local supplier here that has maple for about $6.00 a dowel at that size.

The last 1 1/2 inch dowel I got from woodcraft was maple, though, and good quality.

I can't remember where I saw the bigger ones, but it wasn't woodcraft.

[Pam Niedermayer]

I do not advise trying to use a dowel. Gluing it into the handle will probably soon fail from twisting stresses. Also,are there any 2" dia. dowels?

Since I don't use dowels,I'm not familiar with what's available.

I haven't a clue, usually dowels are too short grained. However, I'm not precluding that there aren't sufficiently large dowels of sufficient quality - they may be out there, maybe from an individual making dowels.

Pam

[Craig Dupler]

I thought I would add to this thread about making larger wood screws (i.e. larger than 1.5") a bit since much has become available (except new tools) over the past three years. There are a lot of videos on the topic on YouTube, but I've only found a couple of guys that seem to have really figured it out. I like the young Mr. Carter the best. In summary, to make a proper screw box, one first needs something to keep the screw advancing properly, i.e. a nut. The very first nut one makes almost certainly requires the slow scraping method because the German taps are not available separately from the dies, and the dies are what make the price so out of sight.

There are several videos out there that talk about using large bolts or even large UNC taps and dies. However, the thread sizes and profiles are all wrong for wood, and produce needlessly weak threads in too fine of a pitch. This is also true of inexpensive screw box kits except for the two smaller sizes (1/2" and 3/4"). The 1" kit is set to 6 threads per inch when it should be 5, the 1.25" kit is set to 6 when it should be 4, and the 1.5" kit is also set t 6 when it should be 3.5.

One thing that the new kits do get right is that they come with two taps, one with a normal taper and one for bottoming. So I think that the real best answer is to make one's own taps by carefully filing the out of thick walled mild steel tubing and to then heat treat them (YouTube has several good videos on this as well).

More later.

[george wilson]

You can't just "heat treat" mild steel tubing and get it to harden. There is way too little carbon in it. Mild steel comes in many types like 1018(.18 carbon),1020(.20 carbon) and various other types.You must have at least .75 carbon to make a decently durable tap. Also,filing out large threads from large steel tubing would be a nearly insurmountable task. You would be removing a triangular shaped volume of steel the dimensions of a THICK saw file,and over 2 feet long.

The most practical way to make a large enough tap would be to have to buy a 2" diameter round piece of drill rod,that costs about what? $200.00? It only comes in 3 foot lengths. You CAN buy it shorter,but then they really jack up the price for the cut off fee. Then,you'd need a powerful metal lathe to cut those large threads. Next,you'd need a good electric furnace (gas would do,but electric is cleaner for the steel) to heat the massive piece of steel up to hardening temp(about 1450º or more,depending upon what type drill rod you used).

I have such facilities,and have thought of making such a tap,and cutting the threads on the male screw with my large lathe. But,then I'd need to have a lasting supply of 4x4" hard maple. I have some,but keeping a steady supply I found was hard as toolmaker. When I did find it,they wanted a fortune for it.

On top of all that,I doubt many would buy these screws. $145.00 has been mentioned as high,but it really isn't when you understand the costs involved. I think I'd be setting myself up for a bunch of work without much of a market.

[Roderick Gentry]

You can harden 1020 with super quench, and you can also build up the edge with hard surfacing rods, none of these are likely to be appreciated by your market.

You may need more than a sturdy lathe to turn your tap threads on since few lathes will produce really large threads. It seriously wears them out, as the loads on the cutter, and the speed the gears need to run at are not conducive to longevity. There is an acme thread that runs the carriage for the cutter, and it has some practical threading to it, conducive to strength, wear, and standard threading work. To get the carriage to move at the rate needed to cut 2-1 threads is just outside the range of most machinery, otherwise it would be easy to turn wooden screws on a metal lathe as is. The South Bend Heavy 10 I have, which is a large small lathe maxes out a a 4 tp1 pitch, and the ability to cut coarse threads doesn't seem to go up much in the larger machines. I understand some users have changed the gearing somehow.

I haven't tried it but other than a CNC lathe, the best results I have seen are from carving the thread. Apparently this can be done successfully, there was an article in FWW at one point.

[george wilson]

The trouble making the tap is the problem with a small lathe,true. I have a 16" x 40" lathe that can do it,though I'd divide up my threading cuts carefully. I have found extra gears for my lathe that greatly extend it's coarse threading(but only for cutting WOOD). It will do 2 TPI with the original gearing. BUT,I'd certainly take auxiliary cuts and build up to the finished cut in tool steel.

I have tried super quench with just slightly improved hardness in mild steels. That is very old information.And,overblown,too. Also,you would have no wear resistance at all. You need carbon content for that. Cutting a thread through a hole is very punishing for the tap. Building up a hard cutting edge might be a way to go,though I'd have to precision grind the weld to get the profile back. Then,there's the internal shape of the cutter to deal with. Look at the closeup of a tap below. At least,the kind I make. An inserted cutting edge is a possibility. But,I'd hate to go to the effort just to find out the cutting edge is coming loose! I prefer solid tool steel,with the punishment the cutting edge takes. A 1/2" deep V in ONE pass!

With these problems,I think I'd just buy the drill rod.

Cutting the actual wood threads is no problem. I use a router mounted at 45º,fed into the wood. No strain on the lathe at all.

Here's a 12" ,6 tpi. one I made for a giant cider press. I made this about 1982. And a few wood taps I made. Some are both right hand and left hand,for making wooden cooper's compares. Also see the thread box for them.I am always making custom wood tap since I often make missing parts from mechanical antiques. The largest one here is 1". These were made to match existing threads on other parts of an antique. You cannot buy decent taps. They all make threads that are too small for wood.

The 6" screw is for the press in the Book Binder's Shop. I am on the left,looking much older!! Jon,my journeyman,a master in his own right,is the other person. Some silly person many years ago,made their book press with a square wood thread,and it fell apart.

I know you are a smart guy,but I hope you see that this is very old hat for me. There were many,many things in the museum needing wood threads,from a bookbinder's stitching frame to the cider press. We even made marking gauges with 3/8" dia. wood screws in the thumb screws. I made the tap for that,too. It's the little one in the picture. I had to take on all comers for 39 years. Toolmaker is not an adequate term,but I could not think of a better one.(Everything maker?) Just doesn't sound right!!:)

Jon was a gunsmith. He got tired of dealing with the public,and joined me in the behind the scenes toolmaker's shop. Jon is one of a few people in the World who can hand forge up a wrought iron gun barrel from a flat kelp. Then,hand ream the tole,and hand rifle it,taking about 600 passes to cut the rifling with a wooden machine. You pull the cutter through by hand,guided by a wooden spiral cut shaft. They make complete guns with the very simplest of tools in the gunsmith shop.

[Dale Coons]

lakeerietoolworks.com makes 2 1/2 inch screws for vises. 2-3 weeks lead time. never done business with them, just know they exist.

maybe they have something reasonable for you?

d

[Jessica Pierce-LaRose]

I have a Lake Erie screw on my bench. I'm very satisified.

[george wilson]

I hope someone makes them. I am tired out at my age,and do not intend to get back into production. My skeleton is pretty worn out. Bone on bone joints,constant pain,have to be careful how much I lift,etc.. I used to be 2" taller.