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wierdscience
03-02-2005, 08:18 PM
Okay,as promised some wooden bench screw pictures.All pieces are turned from Lignum Vitae.
The large screw is 2" od 3TPI in a 45* form.
The smaller one is 1-3/8-6TPI in a 60*form.

Boy LV machines nice!
http://img.photobucket.com/albums/0903/wierdscience/DSCF0002.jpg

Finished large screw-
http://img.photobucket.com/albums/0903/wierdscience/DSCF0006.jpg

1-3/8-6 with a new standard 60* hex die,nice and clean.
http://img.photobucket.com/albums/0903/wierdscience/DSCF0008.jpg

And finally the tap,I didn't make this,the guy who I am turning the screws for did.It just has the one hole drilled radialy which acts as the cutter.The hole in the center allows the chips to fall out and not foul the tap.
http://img.photobucket.com/albums/0903/wierdscience/DSCF0009.jpg

wierdscience
03-02-2005, 08:24 PM
On the tap there are things I would do different.
One would be to make the cutting tooth about .015" higher than the rest of the thread to allow clearence,this one dosen't have any since the big threads get single pointed in the lathe.

Also when using this tap a lot of pressure is needed to get the first thread started and to complete the first crank.I believe I would make a provison for a leadscrew of the same pitch to pull the tap into the hole being tapped,then again it may not be needed on the smaller threads.

Michael Az
03-02-2005, 09:45 PM
Nice work!
Michael

snowman
03-02-2005, 10:01 PM
what's it for?

how much did that piece of wood cost yoU? (scared to hear the reply!)

-Jacob

precisionworks
03-02-2005, 10:02 PM
Lignum Vitae is an interesting wood. WeirdSci, no disrespect is meant by saying that the bark of the LV tree was used in times past for medicinal purposes; namely, to treat syphilis. Don't laugh, it's true.

It is well known as the heaviest & densest wood in the world. On sailing ships it was used for sheave blocks. Here's one link for wooden bearings:
http://www.woodex-meco.com/woodhome.htm
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Your cut threads look awesome. Did you use a follower rest?

snowman
03-02-2005, 10:05 PM
i've just wanted to get some to make some mallets for quite a while.

we have some at work and they are awesome!

-jacob

WJHartson
03-02-2005, 10:38 PM
The picture looks as good as the real thing I saw yesterday during my visit. You did a great job on them. I would like to see the finished work bench.

Joe

elbryant
03-02-2005, 11:21 PM
Magnificent, Wierd.

The die is interesting enough that I might even try going that way. Perhaps while single-pointing it, with the compound at 29*, one could crank it in the equivalent of .015 AFTER that first part, the cutting tooth.
Very ingenious.

I suffer badly from wood lust, so those pictures were pretty hard to take!!

The choice of a 1/3 pitch for the 2 inch screw was the right one. I would have use 1/3 or 1/3.5 instead of the 1/4, but 4tpi is as coarse as my lathe will go. UNLESS MAYBE SOMEBODY CAN TELL ME HOW TO CHEAT A COARSER THREAD OUT OF IT??

wierdscience
03-02-2005, 11:34 PM
Snowman,it's for a LARGE Shaker workbench.Buddy down the road is building his second one.I cut the screws for the first about 4 years ago,then he got an order for this current one from a private collector.
Wood he already had,but it's running $4.25 per pound for sections that large right now which works out to about $150.00

PW (no disrespect http://bbs.homeshopmachinist.net//biggrin.gif ) no,didn't need a steady rest,that stuff is strong.Yep,knew about the medicinal uses(Lingnum Vitae-wood/life)also have seen propeller strut bearing made from it in the 16-26" bore range.Also bearings and guitar picks and tuning pegs.

Turning it is fun,it makes really thin translucent shavings that fall apart in mid-flight.I kept being reminded of something by the smell it has when it's being turned,then it dawned on me,Sweet feed! Smells just like sweet feed for horses http://bbs.homeshopmachinist.net//biggrin.gif
Threading is nerve racking,push it a little too hard and the crest chips,plus as Joe will tell you it's extra fun when you have 15,000 customers asking you questions every 5 minutes http://bbs.homeshopmachinist.net//biggrin.gif

Thanks for the compliment Joe,I am going to try and get pictures of the finished product in a couple weeks.

wierdscience
03-02-2005, 11:47 PM
<font face="Verdana, Arial" size="2">Originally posted by elbryant:
[B]Magnificent, Wierd.

The die is interesting enough that I might even try going that way. Perhaps while single-pointing it, with the compound at 29*, one could crank it in the equivalent of .015 AFTER that first part, the cutting tooth.
Very ingenious.

B]</font>

Good idea,I also would use some Kasnet on the cutting tip.This one he made from an old pinion shaft,it's about 45-50 Rc I guess.
You can't see it so good in the pic,but he dropped it the otherday and of course it landed squarely on the tip http://bbs.homeshopmachinist.net//eek.gif what's that they say about buttered bread always landing buttered side down http://bbs.homeshopmachinist.net//biggrin.gif

Cheat a lathe? Sometimes just swaping the stud gears will 1/2 the pitch counts.

The tread angle on the big screws is 45* for a good reason,the 60* don't work as good on vise screws,the Shakers used the 45 because the 60's would tend to flake off badly over time so I have been told.

I did have one scary moment thou,turned the test nut on the first screw,it went on easy enough with just a little friction,then I tried to unscrew it,it bound! Arrgh....I was sweat'in it backing it off,I could just see a pile of splinters http://bbs.homeshopmachinist.net//biggrin.gif

elbryant
03-03-2005, 01:26 AM
I will have to try 45* on the next big screw I do. That is an interesting point, and of course I always think 60* because that is what we are used to.

Friction isn't good on wood screws. I had one test when I was working on this last project, by the time I got the nut off, the screw looked like a round toothbrush. It wouldn't be so bad if the wood weren't so expensive... I grew up in the pacific northwest where the big (relatively) soft maples were six feet in diameter. I used to burn maple in the stove. http://bbs.homeshopmachinist.net//eek.gif

CCWKen
03-03-2005, 02:16 AM
Dang, that's purdy!
Makes my mallets look like rocks on a stick. http://bbs.homeshopmachinist.net//biggrin.gif

[This message has been edited by CCWKen (edited 03-03-2005).]

wierdscience
03-04-2005, 10:27 PM
Delivered the screws today,even got paid! http://bbs.homeshopmachinist.net//biggrin.gif Whohoo!more tool money for me http://bbs.homeshopmachinist.net//biggrin.gif

Should have pics of the finished product next week.

Thrud
03-04-2005, 11:50 PM
Nicely done!

I think it WOOD look better on my bench nudge, nudge, wink! wink! http://bbs.homeshopmachinist.net//biggrin.gif

wierdscience
03-05-2005, 12:02 AM
I hear you Dave,just as soon as I get 10 minutes http://bbs.homeshopmachinist.net//biggrin.gif

Paul Gauthier
03-05-2005, 12:13 AM
I'm real happy this thread came up because I am going to make a new vise for my bench soon and would have done a 60* thread had Wierd not posted his lovely screws.
Thanks

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Paul G.