For those that installed a set of Rubners on an Eastman Mandolin

[Don Herring]

I have read here that the existing holes need to countersunk for the Rubner tuners.

What tool did you use for the countersink?

Thanks

D

[Mandobart]

Countersinking is used when a builder drills for the tuning machine rollers from the back, then drills to accomodate the bushings from the front. Some builders just drill straight through with a bushing sized hole. You can get various bits from Stew-Mac or many others for this. I've changed out tuning machines on 7 instruments and some had counterbores. When the new bushings are larger than the existing counterbore I use a tapered reamer or stepless tapered drip bit to get the hole's entry to match the bushing OD. Then I choose a drill bit that matches that entry size and finish enlarging the countersink to the right depth for the bushing. I do most of this with hand power (not chucked up in a drill).

It's not an Eastman, but my Cricketfiddle F5 has a standard F style headstock with straight-through bushing sized holes. I didn't have to countersink anything when I installed Rubner machines.

When I changed out the tuners on my Eastman mandocello (F style headstock) for Schaller's there was no need to countersink for bushings either.

[maxr]

If the Rubner tuners have the same diameter shaft as the OE tuners, you may be able to leave the existing bushings in your 305 - I did on mine when I replaced with better Chinese unbranded tuners. The Eastman tuner plate appears to be a little shorter at the top end that some, I had to drill a new screw hold for the top fixing hole on each side - not a great problem.

[Don Herring]

Thanks for the responses.

I just finished installing these on my MDO305. I was able to make use of the existing bushings, but did have to ream the post holes a bit to accommodate that lip (or whatever) at the bottom of the post on the Rubners. I have a set of forstner bits that I used to enlarge the holes by hand.

Four of the existing screw holes line up, and I had to drill a pilot hole for the fifth towards the end of the peg head.

All good, and so much better than the stock tuners that came with the thing.

D

[Ranger Bob]

I did the same thing on my MDO305. Very happy with the results.

[Kenny]

I installed Rubner tuners on my MDO305 a few weeks ago and I used a step drill on the back of the headstock. I just turned it by hand because using a drill press or drill motor you’d risk going too far into the wood.

I just had a full setup done and this MDO305 is now a pleasure to play.