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Double Bass Wooden Bridge Adjusters - how to make?

B

basswraith

Mar 10, 2003
210
4
Boston
www.bostonbassworks.com
#1
Most wooden bridge adjusters available are made to
7/16 -14NC.
I would like to try to make my own. The only thread cutting system for wood is sold for a 3/4 size dowel at the smallest. This is too big make wooden adjusters with.
My question is how are the threads cut to make the 7/16 -14nc without tearing up the wood. I have tried it on a lathe and the wood just tears too easy. Even after soaking it in oil.
How does Lou DiLeone make his adjusters so clean?
I have access to a Sherline milling machine and some other things. I would like to try making a set for my self.
Does any one know how to thread the maple at this size?
:confused:
 
#3
Matthew Tucker said:
can't you just use a metal tap and die?
Click to expand...
I've never managed to get it to work. It tears the wood instead of cutting it. I would love to know how Bob Stenholm made them (from wood). They are works of art. There is a Invalid Link Removed, but it wood be too course for bridge adjusters. If I were going to make a device for making adjuster size threads, I would probably base it on the Beall Wood Threader and use Dremel or Foredom tool instead of a router. I started to make one once, but never got around to finishing it.
 
#4
A buddy of mine turned some on the lathe and turned them to wood screw threads (reversed on each end).

They turn in and out at the same time, then drilled as small pilot hole in the maple bridge and foot for the screw to turn in and out of...

It works as they are on several bass's now for several years with no failures in the bridges or screws.
 
#6
basswraith said:
Most wooden bridge adjusters available are made to
7/16 -14NC.
I would like to try to make my own. The only thread cutting system for wood is sold for a 3/4 size dowel at the smallest. This is too big make wooden adjusters with.
My question is how are the threads cut to make the 7/16 -14nc without tearing up the wood. I have tried it on a lathe and the wood just tears too easy. Even after soaking it in oil.
How does Lou DiLeone make his adjusters so clean?
I have access to a Sherline milling machine and some other things. I would like to try making a set for my self.
Does any one know how to thread the maple at this size?
:confused:
Click to expand...
You have to run the dowel through a router bit while turning it at the right pitch. It requires a jig and a bit which cuts at the proper angle.
 
#7
It looks like one of the easiest ways to do it might be to buy one of the 1/2" Beal Wood Threader kit and then machine your own substitute Delrin insert to what ever thread size you want to make. Finding a router bit cutter the right size might be a problem, but you could probably have the Beall cutter reground to the proper angle by a good shapening shop if it didn't work as is. That sounds like a fun project that I may try myself.
 
#8
KSB - Ken Smith said:
Sounds almost insane to me when you can buy some great ones. Arnold put these in a few of my Basses and they are great.
Click to expand...
What is insane about it? Those adjusters look like Stenholm's and if they are recent, they aren't ebony. If you look on Arnold's NewStandard webite, you see that he laments that the shafts are now made of composite fibre instead of ebony. If you can't buy what you want, you make it yourself.
 
#9
KSB - Ken Smith said:
I believe my adjusters are PART Ebony and part Delrin or some other composite. "I" am happy with them for what ever that is worth. For the Basses I have and have in Restoration, these are the adjusters I now prefer on the finest Basses I have ever had.
Click to expand...
I agree that the Stenholm's are the among the best adjusters out there. FWIW, I have sets of the old original ebony shaft Stenholms on several of my basses (which are not the finest Basses I have ever had). Unfortunately, you can no longer get them with ebony shafts.
 
#11
arnoldschnitzer said:
The ones I've been using are from Lemur. They have a 10mm ebony shaft/screw and a phenolic wheel. Very nice.
Click to expand...
Interesting. 10mm is just over 3/8". Are the threads metric? It looks from Ken's photo to be a knockoff of the Stenholm/Robertson adjusters. I always marveled at Bob Stenholm's workmanship on the ebony threads. Are the Lemur adjusters equal to that standard?
 
#14
I agree with modifying the Beal wood threading kit to receive a smaller sized dowel. Too bad it costs so much $. I might try to re create it.

Is it possible to use a drill press instead of the router?
Would a drill press be at the wrong speed for this ?

Why make a set of Maple adjusters?
Well there are not many people that make them at all. They are not available from any commercial catalogue either.
Also I have some colleagues that have requested them for there symphony basses.
And lastly , cuz I feel like it.
 
#15
Bob Branstetter said:
Interesting. 10mm is just over 3/8". Are the threads metric? It looks from Ken's photo to be a knockoff of the Stenholm/Robertson adjusters. I always marveled at Bob Stenholm's workmanship on the ebony threads. Are the Lemur adjusters equal to that standard?
Click to expand...
Yes, the threads are metric, and yes, the workmanship is equal. Thankfully, the pilot hole for the unthreaded shaft is the right size for cutting the threads on the other side. You only drill once, and this helps keep everything accurate and tidy.
 
#16
basswraith said:
Is it possible to use a drill press instead of the router?
Would a drill press be at the wrong speed for this ?
Click to expand...
The drill press speed might be fast enough, but it would be iffy at best. The Beall is setup for mounting a router and and there would be an alignment problem without a mounting plate. Plus - You don't have much room for error with those threads, so alignment would be critical. Every home shop should have a router anyway:)
 
#17
arnoldschnitzer said:
Yes, the threads are metric, and yes, the workmanship is equal. Thankfully, the pilot hole for the unthreaded shaft is the right size for cutting the threads on the other side. You only drill once, and this helps keep everything accurate and tidy.
Click to expand...
Now that is a great improvement. I never have understood why all adjusters (Aluminum, Brass, Wood, what have you) are not made that way. I've kept an old Unimat mini-lathe in my shop for years just for turning down the non-threaded end to the diameter of the thread drill size. It would be nice not to have to mess with that or worse enlarging the hole while fitting them. Thanks...
 
#20
I really like the adjusters that Nick used on my Shen. They are big and easy to turn. Also, the threads are coarse and not a fine machine thread. This makes more sense to me in wood. Plus, it takes less turning to move the bridge.

They seem to be made of some sort of plastic or other composite material.
 

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