Dovetail Depth of Cut

12145 Views 10 Replies 8 Participants Last post by lewisppuddy, Nov 19, 2012

Sherwood

Discussion Starter · Apr 23, 2005

I have a Sears Dovetail fixture which requires a 0.50 inch guide bushing and a 9/16 inch dovetail bit for cutting through dovetails. My problem: how do I limit the depth of cut while making sure the carbide cutting edge of the dovetail bit does not slice into the inner diameter of the guide bushing?

I understand, of course, that the router collet can be raised and lowered a small amount and that the bit shank will vary in size. Is the only way to "adjust" for this depth of cut problem 1. buy a bit with a carbide edge that is longer or shorter or 2. attempt to use a dovetail bit with a different vertical angle?

Can any size/diameter guide bushing be used in cutting dovetails as long as the outer diameter of the guide bushing easily moves in and out of the dovetail template guide fingers and cleans the wood completely?

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Woodnut65

· #2 · Apr 23, 2005

Hi, Sherwood: The guide you should use is the one specified for your jig. With the guide and bit mounted you should have clearance between the bit and guide for chip removal. If you use a plunge router be careful not to release the plunge mechanism and cause the bit to come up to the guide. Usually, the instructions for the guide include a rough setting point for the distance the bit should extend downward below
the template fingers. Making test joints would the tell you if the bit is to low or to high... Hope this helps .. Woodnut65

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reible

· #3 · Apr 23, 2005 (Edited)

Sherwood said:
I have a Sears Dovetail fixture which requires a 0.50 inch guide bushing and a 9/16 inch dovetail bit for cutting through dovetails. My problem: how do I limit the depth of cut while making sure the carbide cutting edge of the dovetail bit does not slice into the inner diameter of the guide bushing?

I understand, of course, that the router collet can be raised and lowered a small amount and that the bit shank will vary in size. Is the only way to "adjust" for this depth of cut problem 1. buy a bit with a carbide edge that is longer or shorter or 2. attempt to use a dovetail bit with a different vertical angle?

Can any size/diameter guide bushing be used in cutting dovetails as long as the outer diameter of the guide bushing easily moves in and out of the dovetail template guide fingers and cleans the wood completely?

Welcome! I see this is your first post so let me say it is good to hear from you.

Since you mentioned the 1/2" guide bushing and 9/16" dovetail bit my guess is that you are trying to do a thru joint without the right bit. I'm also guessing that you have the manual. Anyway the manual calls for a Sears bit 25414 that you need to use.... If you have that then you should be all set.......... if not then you will have to get one like it from somewhere. When you see the bit it will be clear why they ask for that bit. Now check to make sure that this # is the bit your jig calls for as mine might be a newer or more likly older one then yours.

As mentioned in the other post make sure the bit can not retract into the bushing if you have a plunge router adjust it so this can not happen.

The front of the jig has a bunch of standard depth settings which is a good starting spot for getting the bit to the right height. It is also very importain to get the bit centered in the guide bushing....... The guide bushing screws in tight, you should not attempt to adjust the height this way.

Make sure you make a few test cuts before working on your project and read the manual over a couple of times.... they didn't do a very good job on the manual. If they ask for backer boards and spacers make sure you use them... If they call for them to be 1/8" to 1/4" thicker do it.... I've seen some of these jigs used and torn up because the insturctions were not followed. After you see how things work then you might want to play around but get a little experence before you take off on your own.

Ed

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Dewy

· #4 · Apr 27, 2005

The router jig I use has a 7/16" bush and a 1/2" cutter which is never fitted so far in that it touches the bush.
I set the depth with a fine height adjuster and a gauge stick I made at the correct depth of cut for this jig and cutter.

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don caron

· #5 · Sep 15, 2007

i had a similar problem with the Sears. My answer was to cut a bit off the end of the guide, so it would allow the bit to sit at the correct depth. I got good results. I think that as long as the guide can make contact with the fingers, you're going to be able to use it to make your dovetails.
Don Caron

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Joe Lyddon

· #6 · Sep 15, 2007

don caron said:
i had a similar problem with the Sears. My answer was to cut a bit off the end of the guide, so it would allow the bit to sit at the correct depth. I got good results. I think that as long as the guide can make contact with the fingers, you're going to be able to use it to make your dovetails.
Don Caron

W e l c o m e . . A b o a r d !!

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lewisppuddy

· #7 · Nov 18, 2012

I have just gotten the dovetail jig and the previous owner is unsure weather or not he still has the bushing and bits so, I'm interested in how exactly what and where you made the cut and am still unsure 'bout cut depth and all I really want to do dovetails but cannot afford the price of a new one, need to make this work.....somehow!

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greenacres2

· #8 · Nov 18, 2012

A guess, and only a guess...is that the 1/2" guide bushing originally included in the kit had a short snout. Can't speak for others, but the guide bushings included with the Porter Cable jig are about half the depth of all of my other guide bushings--probably not much over a 1/4" deep, or just under the thickness of the template so that they never interfere with the stock.

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greenacres2

· #9 · Nov 18, 2012 (Edited)

A picture...

...can be worth a thousand words. Normal 3/4" and 5/8" brass bushings next to the same diameters from the PC dovetail kit. Note the difference in height.

edit...if that box top looks as good finished as it does in that picture, my daughter-in-law will love it!! I was really disappointed while sanding this afternoon, but there's hope!!