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Using Dovetail Jig - Porter Cable 4212

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Forum topic by wwbob posted 09-25-2011 07:18 AM 6338 views 2 times favorited 18 replies Add to Favorites Watch
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wwbob

110 posts in 1626 days


09-25-2011 07:18 AM

Topic tags/keywords: dovetail jig cutting half blind dovetails jig question

I’m just beginning to use my 4212. I want to cut half blind dovetails. There is a fairly nice video describing how to use the 4212. http://www.woodworkingonline.com/2007/04/30/podcast-20-machine-cut-dovetails/

What I don’t understand is why some of the dovetails are cut on the left side of the jig and some are cut on the right side.

I did follow what the guy in the video said to do, (cutting on the left and right), then compared the parts. I couldn’t see a difference. The height of the drawer was on the suggested size (multiples of 1” plus 1/4”) so maybe there won’t be a difference in the parts.

Any primo dovetailers understand the reasons?

Thanks,
Bob

-- "I like the quiet I hear." - Channing, age 4


18 replies so far

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Mickey Cassiba

312 posts in 1782 days


#1 posted 09-25-2011 07:47 AM

I bought one when when they came out, have yet to use it…I’ll be watching this thread.

-- One of these hammers oughta fix that...

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CharlieM1958

15807 posts in 2969 days


#2 posted 09-25-2011 03:46 PM

I’m not sure this is what is throwing you off, but there are different offset spacers available for different templates. (By offset spacer, I’m talking about the black thing to the right of the “E” in the photo below.

If you have the same size spacer adjusted exactly the same on both sides, there won’t be a difference. But my jig is currently set up with different offsets on the left and right so I can switch templates and cut from the other side without having to switch spacers also.

Don’t ask me to get too specific, though, because I have not used the jig in probably two years.

-- Charlie M. "Woodworking - patience = firewood"

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wwbob

110 posts in 1626 days


#3 posted 09-25-2011 04:36 PM

Charlie M.,

Thanks for the input. I think the video demonstration is trying to keep the drawer top next to the offset spacer. Using both sides of the jig for one drawer seems like extra work. My first drawer out of MDF, worked out OK. Need to be very careful with setup. Once the setup is complete, cutting is straight forward.

Earlier, I tried to hand cut a through dovetails. That was a total disaster. Made two more attempts, then bought the jig. I don’t have to time to develop the hand/eye/muscle/brain skill to do it by hand.

-- "I like the quiet I hear." - Channing, age 4

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ajosephg

1860 posts in 2312 days


#4 posted 09-25-2011 11:52 PM

It has to do with referencing off the same edge of the board.

For example, say you wanted to offset the dovetails for some reason. When you cut dovetails on the left side of the jig, you are referencing off the left side of a given work piece (duh). When it’s time to cut the dovetails on the opposite end of that same work piece, if you just turn the work piece 180 degrees, you would now be referencing off the right side of the work piece, resulting in the dovetails on that end of the board being out of line with the those on the opposite end.

If you want the dovetails centered (as you described) then it doesn’t make any difference. In fact it is easier to just use on end or the other, because you will have to spend time adjusting two stops instead of one.

In my experience, getting the offset stops adjusted properly is the most difficult part of the use of this jig. Somebody ought to invent a micro adjuster for these similar to those that are used to make micro adjustments to table saw fences. (Probably somebody already has, I just don’t know about it, LOL.)

-- Joe

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StumpyNubs

6272 posts in 1551 days


#5 posted 09-26-2011 12:37 AM

“Half blind dovetails” is an offensive term. I prefer the more P.C. “sight challenged canary butts”.

-- It's the best woodworking show since the invention of wood... New episodes at: http://www.stumpynubs.com

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wwbob

110 posts in 1626 days


#6 posted 09-26-2011 01:00 AM

Joe,
Your information is going to save me a lot of work, thanks. You’re right about getting the offset spacer correctly set.

What is the application for different offsets? Charlie M. mentioned using the spacers for different jigs. I’ve read the manual and the supplement manual and have not seen any example that uses both sides of the jig for a single application.

-- "I like the quiet I hear." - Channing, age 4

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ShaneA

5452 posts in 1349 days


#7 posted 09-26-2011 01:09 AM

When I have used it, I reference the drawer sides off the left only for half blind dovetails. I have the thru template and box joint template, but have yet to try them, and am certainly not an expert with this jig…it takes a while to get it set up to produce good results. Lots of trial and error on scrap pieces.

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wwbob

110 posts in 1626 days


#8 posted 09-26-2011 01:31 AM

Did see a good tip at the router forum, http://www.routerforums.com/

Use the scrap pieces on the opposite side to balance the clamp pressure. The dovetail joint will hold the vertically cut part. Works really well.

I hope to use S.C.C.B. joints, (sight challenged canary butts) for most of my projects. .

Thanks all.

Bob

-- "I like the quiet I hear." - Channing, age 4

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Howie

2656 posts in 1674 days


#9 posted 09-26-2011 02:02 AM

I have a 4212. Gathers dust. It was just too complicated I thought. I “played” with it for three days and finally gave up. Bought an Incra and never looked back.
For what it’s worth there is TWO sets of directions for the 4212(the original book and one on the internet in case you didn’t know this)
BTW mine could be bought cheap and it is complete.

-- Life is good.

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ajosephg

1860 posts in 2312 days


#10 posted 09-26-2011 03:12 AM

”What is the application for different offsets?”

I’ve yet to use a different offset, but hypothetically, I could envision a box where one might want a different distance between the top edge of the box and the first dovetail than the distance from the bottom edge to the nearest dovetail. In that situation you would need to use the guides on both left and right sides of the jib.

I couldn’t find the router forum tip you referenced, but I think I see what you’re talking about. It’s great idea that I’m going to use. A major frustration has been having the scrap spacer board fall on the floor when opening the clamp to remove the work-piece.

-- Joe

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ShaneA

5452 posts in 1349 days


#11 posted 09-26-2011 03:47 AM

I think the other offsets or the stops on the right side are for different templates. But that is just a guess.

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ajosephg

1860 posts in 2312 days


#12 posted 09-26-2011 04:02 AM

Shane – the jig comes with 2 sets of offset guides. The black set is for quarter inch box joints and miniature dovetails, and the silver set is for half inch box joints and standard dovetails. Each set has a left hand and a right hand guide.

-- Joe

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ShaneA

5452 posts in 1349 days


#13 posted 09-26-2011 04:37 AM

Learn something new everyday. I have been meaning to try something other than half-blinds. Just haven’t brought myself to it yet. Have you ever tried it for the box joint? When I have tried box joints with home made jigs on the TS I have not been happy with them.

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ajosephg

1860 posts in 2312 days


#14 posted 09-26-2011 05:02 AM

I’ve used it to make of number of boxes using 1/4 inch box joints, works great. I think they are easier to make than dove tails.

While I’ve never tried to make a TS saw jig for box joints, it seems to me that using a router jig like the PC is certainly faster, and probably results in better outcomes for most people.

Here’s a tip that I’ve learned the hard way, whether making dove tails or box joints. Keep the “clock” position of the router the same. That is to say if you’re looking down at the router while its cutting, and if the handles are at 9:00 and 3:00 o’clock, keep it that way for all of the cuts. This is because no matter how much you try to get the guide bushing exactly centered in the router base plate, it’s not going to be perfect. So – if you make some of your joints with the router clocked different than other joints you will have a fit problem.

-- Joe

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ShaneA

5452 posts in 1349 days


#15 posted 09-26-2011 05:12 AM

thanks joe, I will try to maintain the same same handle position next time I break the jig out. Does it cut 1/2” joints or 1/4” joints? I was thinking mine came with a 1/2” straight bit. Could I also use a differnet guide bushing and a 1/4 or 3/8” straight bit?

One more question…I think it comes from PC with a 7 degree dovetail bit. Could I use a 14 degree as a replacement, I think they look better in my opinion.

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