# Guide bushing clearance



## NoChatter (Dec 4, 2010)

So I am using a guide bushing for the first time with a 1/4" shank 1/2" 14° DT bit and it does not clear the 7/16" bushing. That is to say that I pulled the bit out as far as I thought would be the safe distance out of the collet and the bit still hits the brass bushing.
Do I need a longer shanked bit for this technique? The diagram I am following says the bit should be a 1/2" from the baseplate. TIA


----------



## bobj3 (Jan 17, 2006)

Hi Mike

That would be the easy way

#5405 
Extra Long 1-3/4" Shanks

MLCS dovetail, candlestand router bits

========



NoChatter said:


> So I am using a guide bushing for the first time with a 1/4" shank 1/2" 14° DT bit and it does not clear the 7/16" bushing. That is to say that I pulled the bit out as far as I thought would be the safe distance out of the collet and the bit still hits the brass bushing.
> Do I need a longer shanked bit for this technique? The diagram I am following says the bit should be a 1/2" from the baseplate. TIA


----------



## NoChatter (Dec 4, 2010)

As an update I wanted to post that there is no way a 1/2 " DT bit will fit a 7/16 guide bushing with a height of 1/2 from base plate. Funny that these were instructions from a Woodcraft article but unless there is something I am missing this article is flawed.


----------



## Quillman (Aug 16, 2010)

Bushing can be ground to shorter length. You can waste some of the brass with the carbide cutter itself, and some collet nuts (B&D 3310 e.g.) are made to fit deep into a collar ring. Some subbases are very thin and will allow that amount of extension as well.
Notwithstanding all that, it's a crummy situation. A marginal assembly/application, one (dovetailing with a router) already on the fringes of busting cutters and stretching the limits of what routing was originally intended.


----------



## bobj3 (Jan 17, 2006)

Hi Mike

Note the picture you posted,, the template is 1/2" thick the norm and the guide has 1/4" long stem. they make many types of dovetails bits from 10 deg. to 15 deg., the normal dovetail bit is 12 deg.for most dovetail jigs, so to say you may be using the wrong type of dovetail bit with your jig.. 

http://www.routerforums.com/jigs-fixtures/23304-jig-cut-off-brass-guides.html
==========



NoChatter said:


> As an update I wanted to post that there is no way a 1/2 " DT bit will fit a 7/16 guide bushing with a height of 1/2 from base plate. Funny that these were instructions from a Woodcraft article but unless there is something I am missing this article is flawed.


----------



## Mike (Nov 22, 2004)

Mike, the bit will fit in that bushing. You are assuming the bit "height" is set from the face plate but in the illustration shown the "height" is measured from the bottom of the jig fingers which allows clearance.


----------

