Source For Large Diameter Threaded Dowel??

[daryl1138]

Does anyone know of a source for large diameter 1-1/2"+ threaded dowels. All my search has turned up so far are the Beall jigs. This would work but I only need a foot or two and the jigs are pricey. Harbor freight has a cheaper unit but it's only 1" and...well...it's harbor freight. Shop-made thread box (such as in the Workbench Book) is a bit beyond my capability as yet. I'd just as soon buy the dowel (and nut) already made.

Thanks in advance. Daryl

PS: If it matters this is to be used in a bench vise.

[CobraPilot]

Mike Dunbar wrote an article for Fine Woodworking Tools & Shops special issue (Winter 2001/2002, No 153) in which he described building a workbench with wooden vice screws. The screws were pruchased from Crystal Creek Mill, PO Box 41, DeWitt, NY 13214, Telephone [phone]. Contact Howard, he has or can make just about any size screws and nuts you want.

[David Hall]

Speaking of this, has anyone used the HF wood "tap & dies"? Are they any good?

Dave Hall

[Andy Dingley]

Make them. If you're into the bench-vice size, it's not too much of a chore to cut them by hand. It's easier than hand-forming threads in a small screw.

-- Die Gotterspammerung - Junkmail of the Gods

[BRuce]

Woodcraft has the taps and thread boxes. I have the 1 1/2" set and have used it for a adjustable stool post. The threadbox takes a little tuning but the results are good, depending on the material.

the taps work just fine right out of the box. I did a short test bolt and a "pine nut" that I keep on my desk at work as a conversation piece. the concept of wooden threads seems to elude most people almost as if there never was anything not made of metal!

BRuce

this l> Does anyone know of a source for large diameter 1-1/2"+ threaded

[Charlie Self]

BRuce states:

Odd, considering that push broom handles were wood screw ends into wood threads until just recently.

Charlie Self "Character is much easier kept than recovered." Thomas Paine

[Larry Jaques]

On 25 Jan 2004 16:56:16 GMT, [e-mail] (David Hall) brought forth from the murky depths:

I have the 3/4" model and it's OK. The quality of your dowel makes a whole lot of difference, though.

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[daryl1138]

I have a good idea how you would cut the male thread but how would you get the matching female thread?

[Robert Bonomi]

Those who have never seen an adjustable piano stool, or a dis-assembled push-broom (or floor-wax applicator), I guess.

[Andy Dingley]

Generally you use a metal-cutting tap. These are hard to find, but they do sometimes show up (old tooling from steam engine fitting works for me). You might like to grind the flutes bigger to give more chip clearance, but they'll usually cut fairly well. A die OTOH, doesn;t work for threading wood.

In big sizes, then find Diderot's encyclopedie (or similar ancient reference book) and look for illustrations of how it used to be done. The usual way is with a point cutter and a couple of pointed guide pins, suitably arranged to form the helix. It's a painstaking process, because you have to make sure it doesn't slip out of the guidance groove as it first starts to cut.

Another good way (and how I've done it) is to use a metalworker's screwcutting lathe. Clamp the wooden "nut" to the cross slide and set up a boring bar between centres to carry the threading tool. Once you have it set up, you can bang them out in no time.

-- Die Gotterspammerung - Junkmail of the Gods

[BRuce]

most of the folks where I work are either high end hi-tech or H1Bs. the

1st group probably have never seen a push broom and the second group for whatever reason seem to be amazed at anything that I make from from wood.

i have several old broom handles out in the shed and can remember using them since i was in high school but a lot of "younger folks" probably have never used one.

I think the a lot of the amazement may be more from the perspective that it could be done outside of a factory by a person they know.

BRuce

Charlie Self wrote:

[dave]

Woodcraft seels both the Beall system for wood threading and a less expensive one in a variety of sizes. They come with a tap and a die. Another use for mineral oil in the shop.

Dave in Fairfax

[Andy Dingley]

Doesn't go big enough for a bench vice screw though ?

[Larry Jaques]

On 25 Jan 2004 19:17:47 -0800, [e-mail] (daryl1138) brought forth from the murky depths:

Make a tap. See Underhill's "Woodwright's Workshop" for pics and detailed instructions on how to make your own parts, both taps and dies (screwboxes).

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• Blessed are those who can * Humorous T-shirts Online

• laugh at themselves, for they * Comprehensive Website Dev.

• shall never cease to be amused *

[BRuce]

I plan to use 2 - 1 1/2" for a tail vice, you are looking to hold the wood not squeeze it into submission. If I can sit 200 lbs straight down onto the one in my shop stool, it should be able to clamp a board so i can plane it.

BRuce

Andy D> On Mon, 26 Jan 2004 18:44:46 GMT, [e-mail] wrote: > >

[Andy Dingley]

It's a question of helix angle. You need at least a certain pitch on a vice, or else you'll be winding it in and out all day. If you cut this onto too small a diameter, the angle of the thread is too steep and it doesn't hold.

[BRuce]

I confused, wouldn't the helix angle be the same regardless of the diameter? threads per inch is threads per inch. the angle doesn't change but the surface area changes.

Yes, I will have to run a lot of turns when changing from one operation to another but if I am clamping a board to plane, a single turn release or to reclamp the board is all that will be needed. most metal bench vices have fairly high TPH and some do have quick release.

Once my bench has been finished I will post pictures and number of turns full open to full closed.

BRuce

Andy D>

[Bridger]

the angle decreases as diameter increases.

think of one rotation as a triangle. height is thread pitch- it stays the same. width is diameter- it changes, so the diagonal must change too.

[Alan McClure]

True, the thread on a bolt or dowel is a rolled up inclined plane, one of the basic machines.

The dimensions of the defining triangle is: Height = distance between peaks (or grooves) Base = circumference of cylinder (diameter * pi) Hypotenuse = Length of one turn of the thread.

Thead angle will be arcsine(Height/Hypotenuse) or arctan(Height/Base)

Increasing the diameter of the cylinder will make the triangle longer and thus make the angle smaller.

When the thread angle is about 45 degrees or more the screw and nut can and is used backwards. In other words, instead of using the screw to move or tighten the nut, the nut is moved to cause the screw to rotate. Linear motion is turned into rotary motion. A good example would be the "yankee" screwdriver.

ARM