Arnquist bridge mod

Started by ilan, May 19, 2008, 09:21:45 AM

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ilan

Here's a brilliant new (to me) Mark Arnquist bridge mod. He has kindly agreed to share the pics here.

Arnquist's description:

"As the saddle chassis tilts away from the neck ... by drilling the former screw alignment points all the way though the base.. this makes the base a holder for the screws.

Changing those screws out from 3/4" to one inch hex screws  gives you all the adjustment you need.
The hex screws under the bridge in the cavity are used for the saddle chassis feet to sit in.

After the re-assembly of the bridge ..it appears as stock, the chassis remains upright and has plenty of up and down height variation.

By having a good anchor and being held upright you also get better sustain."


1. Post holes drilled through:



2. Bridge feet sit inside hex screws:



3. Feet anchors installed under bridge base:



4. Saddle chassis feet indents drilled out:



5.



6. bridge feet extend through base now:



7. Base becomes support for chassis:



8. Modded bridge re-assembled:


Dave W

If I understand this right, what he's done is make the floating bridge into a fixed bridge. I suppose that's okay if you don't like the floating bridge.

ilan

#2
With Arnquist's mod the bridge posts make direct contact with the body to transfer string vibrations, like in any other bass I know. With a stock Ric unit, the bridge posts touch the cast tailpiece, which has a clearance from the body. The tailpiece absorbs some of the string's energy. That's why some Ric owners stack washers on the three anchoring bolts between the tailpiece underside and the body, directly under the bridge chassis, so that there's metal-to-metal contact all the way from the bridge saddle down to the body. This very simple trick gives slightly longer sustain and better E string respose (it's also supposed to stop tail lift). The Arnquist mod is a more elegant and professional way of doing this, and has the added bonus of supporting the bridge chassis so that it doesn't tilt back and affect intonation. It's still a floating bridge, held in place by string tension only, and if you remove the strings, it falls off.

Dave W

It may increase sustain, but if it does, it's by reducing absorbed or lost string energy, not by transmitting string energy to the body. More energy to the body equals less sustain.

It's a mod I wouldn't choose, but to each his own.

bobyoung

I have a 79 4001 with holes drilled through the bridge holes similar to that one except that it has extra long Allen screws in it that have flat rounded bottoms which go right in to the wood of the body under the bridge, this is probably my best sounding Ric bass and evidently it was done at the factory as one person has found many 79's with the same design. This design also keeps the bridge standing up straight no matter how high or low you adjust it.
I think this bass has a little less sustain than most but as a result is more punchy than many and lends itself to finger plucking very well. This bass the way it is transmits more of the energy into the body, it also has a wooden nut and the varnish was taken off at some point, is a very organic sounding bass and one of my favorites, hey good to see everyone here, this is my first post BTW.

Dr Quist

#5
Actually this mod was NEVER done at the factory ... it is however a very common mod done by lots of repair shops.  

I fine tuned this mod by using the steel screws in the body to 'Keep' / hold the height screws in place and to keep the height screws from digging into the wood as you adjust them or from string pressure .

This is only part of the bridge problem.

There is also the general location issue.
If you have a 1970's bass.. you can see a section of wood on the neck side inside the mute area...    the bridge base needs to be moved away from the neck , so that the route is nearly revealed.  This will allow you to strobe the "E" string  (.105")  of any modern string maker.. including factory suggested strings.

This is not an opinion .. its fact.
Arnquist Musical Designs
Arnquist Guitars