A different Jig to machine compensated nuts.

You can ask questions here about Trevor and Gerard's exciting new book on Luthiery.

Moderators: kiwigeo, Jeremy D

Post Reply
johnparchem
Blackwood
Posts: 546
Joined: Mon Jan 21, 2013 2:59 am
Location: Seattle
Contact:

A different Jig to machine compensated nuts.

Post by johnparchem » Sat Mar 14, 2015 7:12 am

Not being the best with metal, lack of tools mostly, while making my classical bridge using a jig I based off of one in the book I came up with a different way to machine the nut. It seems to work.

When I made the classical bridge jig I used the rails to make the well so the front edge is parallel to the rails. My bishop Cochran router base adjustment is .8 mm per turn. So 1/2 = .4 mm, 1/4 = .2 and 1/8 = .1. These are all positions that are easy to see.

I made a nut holder that was the same thickness as the fret board so that I could easily set the depth. I zeroed on the front of the nut and proceeded to cut each slot. I had one that string location that I needed to ease the router into the rails. But it came out ok and pretty accurate. I have them all a tad more compensated so that I can clean the leading edge.

Image

Image

Image

Image

Image

User avatar
Trevor Gore
Blackwood
Posts: 1606
Joined: Mon Jun 20, 2011 8:11 pm

Re: A different Jig to machine compensated nuts.

Post by Trevor Gore » Sat Mar 14, 2015 10:37 am

Innovative!
johnparchem wrote:Not being the best with metal, lack of tools mostly, while making my classical bridge using a jig I based off of one in the book I came up with a different way to machine the nut.
In the book I didn't detail how the adjustable compensated nut jig was made, but I did mine pretty much all with hand tools. The adjustable brass blocks are made from 3/8" brass bar, same stock as the bolt bar in the neck. Cut to length with a hacksaw, filed to size, drilled with a pillar drill and tapped M3 (1/8" would be close enough). The rest is made totally from 3/4" x 3/4" x 1/8" brass angle, just sawn and filed to suit. The screw that locks it all up is M5 (10-32 UNF or 3/16" BSF (or even W) is close enough for that. Brass will saw quite well with a standard wood blade on a bandsaw, if you take it easy.

One can probably be made by re-purposing bits of a Strat bridge.

johnparchem
Blackwood
Posts: 546
Joined: Mon Jan 21, 2013 2:59 am
Location: Seattle
Contact:

Re: A different Jig to machine compensated nuts.

Post by johnparchem » Sat Mar 14, 2015 10:50 am

I have some 3/8" brass bar stock on order. So I will give it a go next guitar.

johnparchem
Blackwood
Posts: 546
Joined: Mon Jan 21, 2013 2:59 am
Location: Seattle
Contact:

Re: A different Jig to machine compensated nuts.

Post by johnparchem » Sat Mar 14, 2015 11:58 am

Is there a standard part that can lock the adjustment screw in tight but still allow the screw to turn. I suppose some sort of bearing with a set screw. Maybe two nuts locked against each other and a nylon washer. Something tight but still allows the adjustment. I assume there is something like that in the jig to hold the screw while the adjustment is made.

User avatar
Trevor Gore
Blackwood
Posts: 1606
Joined: Mon Jun 20, 2011 8:11 pm

Re: A different Jig to machine compensated nuts.

Post by Trevor Gore » Sun Mar 15, 2015 10:22 am

It's set up like a Strat bridge. There's a spring (spare part for said Strat bridge) between the "back bar" (which is just the angle part of the base that the adjustable blocks sit on) and the back of each block. Look very closely at Fig 21-18 and Fig 21-19 and you may be able to see the springs.

johnparchem
Blackwood
Posts: 546
Joined: Mon Jan 21, 2013 2:59 am
Location: Seattle
Contact:

Re: A different Jig to machine compensated nuts.

Post by johnparchem » Sun Mar 15, 2015 10:41 am

Thanks, I did check out my strat as well. So the spring gives enough push back to adjust and then you lock the whole stack with the side screw. I get it now. That is a lot simpler than I was thinking.


Post Reply

Who is online

Users browsing this forum: No registered users and 42 guests