# Guide bushing fabrication



## johnpaulh (Apr 27, 2009)

Hello all,
My son recently got into guitar making and wants to do fret inlay. For his first guitar, we did elephant ivory, and I taught him to cut and fit by hand. He wants to go into production making custom bass (electric) guitars, and offer inlay, but of course no one wants to pay the $$$ for the time to hand cut/fit.

To my dilemma.....

My old Craftsman router is just too large for this work, but I have a Foredom, as well as a Dremel....and I have a full sized lathe, plus an adequate metalshop.

We want to rout the tightest radii we can, so I thought I would fabricate a simple plunge type base for the Dremel. I can do the fabrication, but am having a deal of a time figuring out the different bushing sizes. (Actually, the plan is to have a one piece base/guide, and a removable large bushing, so it will be a single purpose tool)

I want to use a 1/8" bit, with the smallest bushings I can utilize. I just cannot seem to wrap my head around the offsets. 

And to make sure I have the process right, guide bushing = small bushing = positive inlay piece. Larger bushing (slips over guide) = negative (inlet) piece. Yes?

My reckoning....1/8" bit with a 3/16 O.D. guide bushing...tight I know. Here is where I "go blind" trying to figure out the O.D. for the large bushing.:fie: And of course, if my understanding of the process is correct, the large bushing dictates how tight the radius can be?

Any and all help will be most appreciated, and of course I will follow up and post pictures of the finished tool, as well as the final product.

Thank you all in advance!

John


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## bobj3 (Jan 17, 2006)

Hi John

No need to fab a base for the Dremel, just buy one they are cheap, as far as the guides bearings will do the job just fine, in fact better..you can get the lock collars from ACE hardware to keep the bearing in place on the 1/8" shaft..


Amazon.com: dremel plunge base - Tools & Home Improvement

MLCS Woodworking Adaptor Bushings and Ball Bearing Guides

1/8" shank router bits at a good price ,see below
http://www.grizzly.com/products/Mini-Bit-10-pc-Set-1-8-Shank/H0880

====


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## Quillman (Aug 16, 2010)

Would not strain at a gnat here. Use smallest bush that is practical, then learn chisel skills to get where the cutter won't.


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## gregW (Mar 14, 2007)

johnpaulh said:


> Hello all,
> My son recently got into guitar making and wants to do fret inlay. For his first guitar, we did elephant ivory, and I taught him to cut and fit by hand. He wants to go into production making custom bass (electric) guitars, and offer inlay, but of course no one wants to pay the $$$ for the time to hand cut/fit.
> 
> To my dilemma.....
> ...



assuming you are using a female template you have the process correct...the inlay piece is routed without the inlay sleeve installed on the template guide, and the recess is routed with the inlay sleeve installed on the template guide..a male template would be the opposite.

The O.D. of the larger bushing (or inlay sleeve) should be the diameter of the template guide plus twice the diameter of the cutter..so in your example a 3/16" template guide used with a 1/8" diameter cutter would require a 7/16" inlay sleeve, or you could just use a 7/16" template guide to route the recess.


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## johnpaulh (Apr 27, 2009)

*Thanks!!!*

Thanks to all for the replies, now it makes sense and we can get started on our projects. 

As to the router base, I am fabricating out of necessity due to budget constraints (I have plenty of aluminum and brass bar stock), otherwise I would jump right on one of the Stewart Mcdonald bases, however that is essentially what I will be making, but with guide bushings/bearings. I may even make the base to work with the Dremel flex shaft tool for better handling. 


Now....in reference to my old Craftsman router, it is one of those with the pinion gear to adjust the height, and the gear apparently was made of zamak or something similar and has eroded. I have looked high, low, and everywhere in between for a replacement. Unfortunately I don't have broaching tooling for my lathe, or would fab a replacement, and there is nothing left to make a mold from to cast a new one from bronze or brass. 

Anyone have a pinion gear kicking around? Maybe on that busted router you haven't gotten around to fixing up?

Thanks again for the assistance,

John and Paul


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## cab938 (Jan 28, 2012)

I'd be interested in knowing where you found a 3/16" OD template guide, the best I seem to be able to find out there are 5/16". I've got a similar need (would have PM'ed you, but I guess it's not allowed on the forum unless you've posted lots).


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## waho6o9 (Apr 4, 2010)

Micro Fence - Precision tools for the discerning craftsman

A little spendy, but very accurate.


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## bobj3 (Jan 17, 2006)

Hi 

Just one more

http://www.amazon.com/Porter-Cable-...ref=sr_1_1?s=hi&ie=UTF8&qid=1327767107&sr=1-1

it will fit almost all routers or you make your own front plate and just drilling two holes to line up the rods on your router and can be used for a great cir. jig as well.
==





waho6o9 said:


> Micro Fence - Precision tools for the discerning craftsman
> 
> A little spendy, but very accurate.


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## bobj3 (Jan 17, 2006)

Solid Brass Router Inlay Kit

OR

You can make your own with the item below and silver solder a brass rod into place and then chuck it up on the lathe and turn it down and drill out the brass rod so the router bit just fits into the hole..note ,,solder the rod in place on the back side (inside) of the guide you will need to turn it flat on the out side(face side) of the guide..

http://www.leevalley.com/US/wood/page.aspx?p=51153&cat=1,43000,51208
==



cab938 said:


> I'd be interested in knowing where you found a 3/16" OD template guide, the best I seem to be able to find out there are 5/16". I've got a similar need (would have PM'ed you, but I guess it's not allowed on the forum unless you've posted lots).


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## istracpsboss (Sep 14, 2008)

johnpaulh said:


> Now....in reference to my old Craftsman router, it is one of those with the pinion gear to adjust the height, and the gear apparently was made of zamak or something similar and has eroded. I have looked high, low, and everywhere in between for a replacement. Unfortunately I don't have broaching tooling for my lathe, or would fab a replacement, and there is nothing left to make a mold from to cast a new one from bronze or brass.
> 
> Anyone have a pinion gear kicking around? Maybe on that busted router you haven't gotten around to fixing up?
> 
> ...


For your side of the pond I would try Boston Gears Bostongear.com your source for speed reducers, gears and power transmission components for industrial applications for a replacement pinion if the original manufacturer doesn't list them.
(Amazing, all I put in was the URL and all that other stuff appears !)

Cheers

Peter


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## johnpaulh (Apr 27, 2009)

*3/16" OD Guide Bushing*

I was planning to fabricate it on my lathe. Haven't progressed much on this project lately due to family issues, but hopefully can get back on it soon. Email me with your specs and I will whip one up for you as well. johnpaulh AT gmail DOT com



cab938 said:


> I'd be interested in knowing where you found a 3/16" OD template guide, the best I seem to be able to find out there are 5/16". I've got a similar need (would have PM'ed you, but I guess it's not allowed on the forum unless you've posted lots).


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