A Simple Machine to make large diameter wooden screws – cont’d
So here’s a pic of the lunettes in place:
The “lead” (or master screw) and the workpiece are connected with a socket and stub joint that is locked with a screw. The stub should be the same diameter as the socket, close to the shoulder, but should be a little tapered away from the shoulder. This will allow for some very probable misalignment. Remember, we’re dealing with wood here and my shop is 90 degrees with a fair amount of humidity.
Set the router to depth (several passes are probably, but experiment), turn ‘er on and start twisting the lead screw.
Forty odd hours later, $50 lighter in your wallet, here’s what you end up with:
Wooden screws, these will be seated into hubs - but blanks with integrated hubs will work just the same
Have fun. You’ll need to experiment a little. But I think you’ll find that it’s very worthwhile.
Explore posts in the same categories: making wooden screws, wooden screwsTags: pole lathe, Roubo workbench, wooden bench screws, wooden vise screws
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August 13, 2011 at 10:36 pm
Thank you very much for posting this.
October 14, 2012 at 11:32 pm
Any chance I could purchase one of these wood screws from you? I’m working on a project and can’t find one anywhere and we don’t have the tools in our shop to make one. Let me know!
October 24, 2012 at 9:21 pm
Check out http://www.lakeerietoolworks.com Great benchscrews, excellent value.
December 5, 2012 at 12:59 pm
Great project. I’ve been following you over on Lumber Jocks. Question. Can this machine be used to turn any diameter screw that is at least thick enough to handle the tenon on the end just by using properly placed ‘Stantions” with the correct diameter hole? Sure would be nice to build this beasty one time and use it for multiple diameter screws!
December 6, 2012 at 2:07 am
Yes, you could use different diameter “stantions” with the existing lead screw. However, the screw pitch (threads per inch) would remain the same. What this would mean is that as the diameter would increase, the “relative” pitch would become finer. You would get to a point of diminishing return in short order, with the thread being so fine that the pitch angle would become, effectively, a “locking taper”. The main reason large diameters are desirable is that they move the “object” (in this case vise chops) a greater distance per revolution. The basic rule is to determine the “pitch distance” (from point to point) by dividing the screw circumference by twelve. For example, the circumference of a 2 1/2 diameter is a little more than 7.5. If you divide that by 12 you come up with approximately 0.6. So the distance between threads is 6/10ths, or about 2 1/2 threads per inch. So, in order to move the object 1″, you’ve got to turn the screw about 2 1/2 revolutions. So a bigger diameter gets you, mostly, more closing speed. (It’ll get you some other benefits like thread strength, etc.) The long and short of it is that “screwmaking” could become a lifetime obsession, if you let it.
March 3, 2013 at 4:14 am
Nicely done! And your comment about screw making becoming a lifelong obsession is quite accurate! I got into it after my first experience with a wooden screw, and have been making ‘em ever since!