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
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
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.
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.
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
I did the same thing on my MDO305. Very happy with the results.
A couple years in, now, and still learning!
Ratliff F-style Country Boy
Eastman MDO-305 Octave Mandolin
Kentucky KM-272
I don’t know what I want to be when I grow up.
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