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PostPosted: Thu Jul 27, 2017 2:06 pm 
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First name: colin
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Got a set of tuners with splined press fit type bushings, outside diameter 10.75-10.78 mm
Fitting to a peghead of mahogany with an EIR overlay.
Does a 10.45 mm drill size sound about right?
That's around 0.012-0.013" less than the bushing OD.
Do I press them dry, or lube with a little water? Or maybe diluted fish glue?
(I intend pulling them in with a soft washer/nut/bolt)

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.


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PostPosted: Thu Jul 27, 2017 3:46 pm 
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Brazilian Rosewood
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I usually drill a hole in a piece of scrap of similar wood to judge the fit . I press them in with an F body (Jorgensen pony) type clamp with
the soft plastic cauls that fit over the ends. Different woods seem to like different size holes.


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PostPosted: Thu Jul 27, 2017 4:15 pm 
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Brazilian Rosewood
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If you plan on doing a lot of them StewMac has guided reamers in various sizes that work well. If not, drilling scrap to determine size is probably best.

I usually like to have them get tight with about 3/64-1/32 proud.

Here is a way to press them that works for me.

http://kennedyguitars.com/tuner-bushing-press.html

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These users thanked the author Terence Kennedy for the post: Colin North (Fri Jul 28, 2017 2:24 am)
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PostPosted: Thu Jul 27, 2017 6:35 pm 
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I use a violin reamer to gradually enlarge the hole until the bushing starts to go in, and then press with a cam clamp. The taper means the highest pressure is at the bottom of the bushing, so it won't split the headplate.



These users thanked the author DennisK for the post: Clay S. (Thu Jul 27, 2017 8:24 pm)
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PostPosted: Thu Jul 27, 2017 10:06 pm 
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Brazilian Rosewood
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I use a reamer too. I've bought the recommended Stew Mac reamer bits and found them to be too small, at least for the mandolin I was working on. Ended up just reaming them out anyway. I just use a C-Clamp and cork lined cauls to press them in.


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PostPosted: Thu Jul 27, 2017 11:27 pm 
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Brazilian Rosewood
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Strong advocate of a tapered reamer to fit here. Most bushings are tapered to begin with, and even for those that are straight I strongly prefer to have a slightly tighter fit at the bottom where it can support more pressure, with slightly less pressure at the top where week or two in dry conditions can leave the surface and finish more susceptible to cracks.

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These users thanked the author David Collins for the post: Colin North (Fri Jul 28, 2017 2:01 am)
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PostPosted: Fri Jul 28, 2017 2:11 am 
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David Collins wrote:
Strong advocate of a tapered reamer to fit here. Most bushings are tapered to begin with, and even for those that are straight I strongly prefer to have a slightly tighter fit at the bottom where it can support more pressure, with slightly less pressure at the top where week or two in dry conditions can leave the surface and finish more susceptible to cracks.

Interestingly the makers seem to have had some PPPPP here - the (straight) splines don't start until about 1-1.5 mm down the bushing, but I was going to taper the top of the hole anyway, just in case they ever want pulling out.

_________________
The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.


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PostPosted: Fri Jul 28, 2017 2:28 am 
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Joined: Fri Jul 10, 2009 4:44 am
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First name: colin
Last Name: north
Country: Scotland.
Focus: Build
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Terence Kennedy wrote:
Here is a way to press them that works for me.

http://kennedyguitars.com/tuner-bushing-press.html

Saw that some time ago Terence, just couldn't remember where.
Much the same as I plan on doing thanks to seeing it.

_________________
The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.


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PostPosted: Fri Jul 28, 2017 7:57 am 
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Brazilian Rosewood
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Joined: Fri Dec 14, 2007 3:21 pm
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Location: Alexandria MN
I actually remembered I made a video a few years ago. I found that the StewMac reamers if used in a hand drill were too loose because of the inescapable wobble, at least in my hands.

A drill press at lower speed was just a little tight sometimes but not bad. I cut off a hardware store plumber's reamer and got it to where it worked well for the final fitting and in conjunction with a #11 blade removing excess finish before final installation.

I over pressed a few at first causing cracks in the Nitro or in the case of a catalyzed finish causing a dent. I am really careful to just get it to touch the finish now.

https://youtu.be/Pm9wlrsH5M8

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It's not what you don't know that hurts you, it's what you do know that's wrong.



These users thanked the author Terence Kennedy for the post: Colin North (Fri Jul 28, 2017 12:52 pm)
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