# PC Dovetail Jig - Special bit??



## Trine_W9 (Jul 31, 2010)

A friend lent me his porter cable dovetail jig model 4212 which was very nice of him since he hadn't used it yet. Problem is that it calls for a 17/32" 7 degree dovetail bit. This is unavailable in town. I will order if I have to but was hoping to build drawers this weekend. Can I use a 1/2" 7 degree which is readily available?


----------



## bobj3 (Jan 17, 2006)

Hi

" This is unavailable in town " = ?????

" Can I use a 1/2" 7 degree " = not the norm, but I will say you can use it if the stock is 1/2" thick the Max..

=======



Trine_W9 said:


> A friend lent me his porter cable dovetail jig model 4212 which was very nice of him since he hadn't used it yet. Problem is that it calls for a 17/32" 7 degree dovetail bit. This is unavailable in town. I will order if I have to but was hoping to build drawers this weekend. Can I use a 1/2" 7 degree which is readily available?


----------



## Trine_W9 (Jul 31, 2010)

As a newbi I really don't know what is norm. I can do a pretty good job following directions. For half-blind dovetails it calls for a 17/32" 7 degree Dovetail bit part no 43776PC. I intend to use 5/8" baltic birch for the drawer sides. 

I don't know why 1/32" would make a difference. Do you?
thanks for quick reply.


----------



## bobj3 (Jan 17, 2006)

Hi

If you are putting Blind dovetails set the bit at 3/8" deep for 5/8" thick stock, you need some meat at the end of the dovetail pass...

======



Trine_W9 said:


> As a newbi I really don't know what is norm. I can do a pretty good job following directions. For half-blind dovetails it calls for a 17/32" 7 degree Dovetail bit part no 43776PC. I intend to use 5/8" baltic birch for the drawer sides.
> 
> I don't know why 1/32" would make a difference. Do you?
> thanks for quick reply.


----------



## jlord (Nov 16, 2009)

Hi Geo.
For half-blind dovetails if you set the depth of your bit to 5/8" from the router base plate (3/8" of material & 1/4" template thickness) this will give you a very close ball park number for good fitting joints. Once your router is set up you can use this same setup for the different thickness of material (1/2" to 1-1/8") as your joints are referenced from the inside of the joint. I have a router setup for half blinds & never have to reset the bit for the different thicknesses unless changing out to a new bit.

The porter Cable jig uses 1" (1" + 1/4") increments in sizing. If you want centered joints you will need to size your drawer heights using this measurement (2-1/4", 3-1/4", 4-1/4", 5-1/4", etc). For example if you have a 6" drawer opening you would rip your drawer parts to 5-1/4" to have a centered joint with half pins top & bottom. Any other height (ex:5-1/2") you will not have centered joints. Keep this in mind if you use this jig to make other things such as boxes, etc. 

Porter Cable does have a supplemental manual that will show some different technics on making joints with this jig. You may need to just buy the different templates.


----------



## Trine_W9 (Jul 31, 2010)

Thanks James for the tip on drawer heights. Do you have any sense of whether or not a must use the 17/32" dovetail bit?


----------



## jlord (Nov 16, 2009)

The supplemental manual might have some info on that, but I use the recommended bit when building drawers. If you use a different size bit the small amount of difference might compound itself the larger the joint. You do need to keep your drawer heights in mind. Some other jigs use 7/8" increments but the Porter Cable uses 1". If you need to use thinner stock such as 1/4" you will need to use the mini template. The sizing is half of what the larger template calls for.

These hard maple drawers were made using the PC jig.


----------



## jlord (Nov 16, 2009)

Here is a pod cast from Woodsmith. Watch podcast # 20 Machine Cut Dovetails. He demos & shows how to setup the PC jig. 
Podcast — Woodworking Online


----------



## Trine_W9 (Jul 31, 2010)

Thank you everyone for the assistance. Nice pics james.


----------



## jlord (Nov 16, 2009)

Trine_W9 said:


> Thank you everyone for the assistance. Nice pics james.


Thanks.


----------



## TwoSkies57 (Feb 23, 2009)

Trine W9....

this was posted a while back by rwyoung, it should pretty much answer your question...

If you browse around on the Porter Cable site, you can get the manual and the supplementary manual. In the supplementary manual on pages 14 you will find a chart giving the sizes for combinations of dovetail and straight bits that work correctly with the jig.

The "standard" sizes are a 7 degree dovetail, size 17/32 paired with a 13/32 straight bit.

The key is that the sum of the two measurements must be 15/16".

The two bushings have outer diameters of 3/4" and 5/8". The inner diameter is less critical except that more is better in the case of the 3/4" bushing so you have more adjustment range in the dovetail bit height.

Definitely download the manuals at the PC site.. well worth having, and load with information...


----------



## jlord (Nov 16, 2009)

There are links to the two manuals in pdf in my signature section. The 15/16" sum of the two bits are for through dovetails. The sum of two bits for blind-dovetails should be closest to 1".

*Page 14 & 15*
*THROUGH-DOVETAIL BITS*
The sum of the diameters
of the dovetail and straight
bits must equal 15/16". For
example, a 5/8" dovetail bit
must have a 5/16" straight bit
- the sum of both equalling
15/16".

*THROUGH-DOVETAIL BIT
COMBINATIONS (READILY AVAILABLE)*
3/4"...........3/16"
5/8"...........5/16"
9/16"..........3/8"
17/32"........13/32"


*HALF-BLIND DOVETAIL BITS*
1. The two bits must have the same angle.
2. A shallower angle requires a deeper cut, while a steeper angle requires a shallower cut.
3. When the diameters of the two bits are added together, the sum must be slightly greater than 1". The closer
the sum is to 1", the shallower the depth of cut will be. The larger the sum, the deeper the cut.

*BIT COMBINATIONS FOR SEPARATE HALF-BLIND CUTS (READILY AVAILABLE)
*
*LARGER BIT / SMALLER BIT / APPROX. DEPTH-OF-CUT*
3/4", 14°.....................1/2" 14°.....................9/16"
5/8", 14°.....................1/2" 14°.....................3/8"
5/8", 7° ......................17/32",7°....................7/8"
5/8", 7° ......................17/32",7°....................1"
9/16", 7°......................17/32",7°...................5/8"


----------



## Dr.Zook (Sep 10, 2004)

Welcome to the router community Geo. Thanks for making our forum better by registering.


----------



## Trine_W9 (Jul 31, 2010)

First, let me thank all of you for you kind assistance. I am also reluctant to tell you what happened next after you went to such trouble to give me the very complete advice and directions. But here it is. 

When I complained about not having the right bit and the delay in getting it on line to my other good friend, he lent me his Leigh D4 with bits. Now it would appear that I could use some direction of what podcasts, articles etc are available for that tool. Could I again trouble you for some assistance or is my currency exhausted after only one post?


----------



## jlord (Nov 16, 2009)

You could search You Tube. There will probably be some videos with that jig, it is popular. Your friend didn't give you any tips on his jig?

http://benchmark.20m.com/reviews/LeighJig/leighjigreview.html


----------



## iluvmysh (Dec 20, 2012)

jlord said:


> Here is a pod cast from Woodsmith. Watch podcast # 20 Machine Cut Dovetails. He demos & shows how to setup the PC jig.
> [woodworkingonlinedotcom/category/podcast/page/3/]Podcast — Woodworking Online]


that video was the coolest video and SOOOOO useful! it should be stickied!


----------

