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By roombacurious
#237921
I've recently attempted to turn a dowel into a screw but failed miserably. I'm obviously not that good at woodturning yet... However I've come across these manual woodthreaders (a tap and die set for wood) which seem easy to use and if they do indeed work as advertised should be the answer to my problem.

Are they any good? Has anyone got any experience with them?

I was thinking to make a bench vice for example, but I'm unsure about a) what type of wood to use for the screw for maximum strength and b) whether you can tighten such a wood screw enough to make the vice useful. Any ideas?
By Inspector
#237972
I had a set to do 1 1/2 inch threads and couldn't make it work for me but the quality of the thread box had a lot to do with it. The cutter needs to be set and sharpened perfectly to work right and it wasn't. My father eventually came up with a better way of cutting them on the tablesaw that worked great. He made several diameters up to 4 inches.

I wrote and posted pictures on the Knots Forum a couple years ago about the method if your interested.

http://forums.taunton.com/fw-knots/messages?msg=7987.11

If you don't want to go that route then get the one for a router that I linked in the above.

All of the bench screws were of wood until the Industrial Revolution and metal lathes became common. Beach or hard maple make good screws, as will any hardwood that is close grained.

There is a book that you might look for.
By Fred Holder
Making Screw Treads in Wood
ISBN 1-86108-195-2
Guild of Master Craftsman Publications.

Have fun.
By pam niedermayer
#237998
Inspector, any chance you can copy that Knots thread to here? I'd love to read it, but don't feel like paying FWW/Taunton right now.

For much more on screw boxes, like how to make your own, check out St. Roy's video 2704 at http://www.pbs.org/wws/schedule/video.html

Also, St. Roy covers this on a video tape from a previous season, 2406 Wooden Thread Cutter: Make your own giant wooden vise screws and nuts with this ingenious hand cranked device. I don't know that this is still available, but it's very good.

Pam
By Inspector
#238000
pam niedermayer

Knots is a free Forum like this one. You just need to register and then read and post to your hearts content. I don't subscribe to the paying side of Fine Woodworking website either.

Reason I don't desire to repost here is that I would need to select a separate photo hosting site and link to here etc., and that's a bit too much of a pain for a one finger typist, especially when it's already out there.
By pam niedermayer
#238010
Thanks for the Knots tip, Inspector, also for the article, very interesting. I don't quite get it, but think I understand how to approach it. But I have to ask if using the table saw is appreciably faster/easier than using a hand saw?

Pam
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By Chris Knight
#238011
Another thought on threads. Some years ago Lee Valley/Veritas published an article on the use of machine screw sized threads in hardwoods, I forget exactly when and I can't now find mention of the article. However, emboldened by that, I have used ordinary taps and dies several times with close grained hardwoods to make threads that have all worked very well.

I use the coarsest threads I can conveniently find for a given diameter. When you get up to about an inch in diameter, the Whitworth threads work particularly well and are actually similar in style and shape to the thread boxes results. You can often find these older thread styles at car boot sales and the like.

I would emphasise however that even the smaller sizes work well in the more common metric threads, provided you use an appropriate wood and lubricate it well with wax whilst cutting the thread.
By lurker
#238012
hi George

I bought a tap & die kit from Craft Supplies 3/4" a few years back and its worked fine and been a very useful tool. Well worth the cost.

I can't see it on the website but it looks exactly the same as this:
http://www.mikestools.com/800-1008-Thre ... 8-Tpi.aspx

Obviously some woods are no good for it but using beech particually it does a good job.

If you over tighen I've found the rod breaks before the threads strip.

I was thinking of getting a big 1 3/4" to make a bench vice but in the end I bought a metal thread from here

http://www.axminster.co.uk/category-Vic ... 208038.htm
By Inspector
#238159
pam niedermayer wrote:Thanks for the Knots tip, Inspector, also for the article, very interesting. I don't quite get it, but think I understand how to approach it. But I have to ask if using the table saw is appreciably faster/easier than using a hand saw?

Pam


The Table Saw has several advantages and a minor drawback or two as well.

Drawbacks: It takes a little bit of time to setup when you want to use it because of the blade changes, clamping the jig over the blade, and then feeding the cylinder through a few times while raising the blade until the resulting thread has the fit your looking for. There is also the need of a special blade although if you have a molding head (not a common item especially in Europe) you only need to modify a set of inserts. There is also some time needed to make the jigs in the first place. The later two are onetime occurrences.

Advantages: The threads are cut very quickly with virtually no tear out and are smooth. The size of the thread (fit) is easily controlled by raising and lowering the blade. The range of pitch sizes is only limited by the blade geometry of the tips. Mine has about a 1mm flat on the tip therefore can only go to about 12 TPI or possibly 16 TPI up to 3 TPI and whatever diameter of tap you can lay your hands on. A blade with a sharper tip will cut higher pitches and smaller diameters. You can feed and cut the thread as fast as you can rotate the dowel (by hand) in the smaller sizes with the bigger diameters a little slower.

Handsaw? Or did you mean hand feed thread box? The Beall system for routers is in principal the same with the main difference being that the saw blade will cut cleaner.
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By roombacurious
#238268
Thanks for all your replies - very helpful indeed!

I think I'll give these screwboxes a try - if I can find them that is... They seem to be a somewhat rare specimen (especially the larger sizes).
By pam niedermayer
#238737
Inspector wrote:...Advantages: The threads are cut very quickly with virtually no tear out and are smooth. The size of the thread (fit) is easily controlled by raising and lowering the blade. The range of pitch sizes is only limited by the blade geometry of the tips. Mine has about a 1mm flat on the tip therefore can only go to about 12 TPI or possibly 16 TPI up to 3 TPI and whatever diameter of tap you can lay your hands on. A blade with a sharper tip will cut higher pitches and smaller diameters. You can feed and cut the thread as fast as you can rotate the dowel (by hand) in the smaller sizes with the bigger diameters a little slower.

Handsaw? Or did you mean hand feed thread box? The Beall system for routers is in principal the same with the main difference being that the saw blade will cut cleaner.


Thanks, Inspector. Let me try to explain how this works so you can correct my mistakes. Basically you tap the threads somehow or other, along with a wood thread chaser, then run the screw-to-be through the blade and into the nut to govern the rate. I'm not quite sure how jig angle forms the pitch or why it's necessary when you have the nut and thread chaser.

By hand saw I meant handsaw to cut the threads, used instead of the table saw blade. It would take a bit more work to get clean threads. For a reference, check out the barley twist shows on the Woodwright's Shop videos online. These don't show thread cutting, exactly, but are indicative of the approach St. Roy takes.

Pam
By Inspector
#238769
pam niedermayer wrote:Thanks, Inspector. Let me try to explain how this works so you can correct my mistakes. Basically you tap the threads somehow or other, along with a wood thread chaser, then run the screw-to-be through the blade and into the nut to govern the rate. I'm not quite sure how jig angle forms the pitch or why it's necessary when you have the nut and thread chaser.

By hand saw I meant handsaw to cut the threads, used instead of the table saw blade. It would take a bit more work to get clean threads. For a reference, check out the barley twist shows on the Woodwright's Shop videos online. These don't show thread cutting, exactly, but are indicative of the approach St. Roy takes.

Pam


http://www.leevalley.com/wood/page.aspx ... at=1,43000

If you look at the link above you'll see how the router cuts the thread. The table saw method is the same but a special saw blade (had it custom made with 60 degree triangular tips) is used instead of the router bit. The blade is aligned with the pitch angle of the thread because if it wasn't it would misshape the thread in the same way a board is presented at an angle to a saw blade makes a cove. A tread tap is still needed to make the female threads. The traditional thread box / chaser / die with its fixed cutter is replaced by the table saw jig which is in effect a thread box with a "live cutter".

The barley twist handsaw method would work for large threads but would need to be completed with chisels & V gouges etc. Probably was the way realy big screws were made in the past.

Hope that clears things a bit for you.
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By bugbear
#238796
roombacurious wrote:I've recently attempted to turn a dowel into a screw but failed miserably. I'm obviously not that good at woodturning yet... However I've come across these manual woodthreaders (a tap and die set for wood) which seem easy to use and if they do indeed work as advertised should be the answer to my problem.

Are they any good? Has anyone got any experience with them?

I was thinking to make a bench vice for example, but I'm unsure about a) what type of wood to use for the screw for maximum strength and b) whether you can tighten such a wood screw enough to make the vice useful. Any ideas?


http://nika.frontier.iarc.uaf.edu/~cswi ... =1#message

BugBear