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Rusty builder needs help with basics on dovetailing jig

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Forum topic by SoonerDave posted 08-16-2010 02:58 PM 2051 views 1 time favorited 13 replies Add to Favorites Watch
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SoonerDave

6 posts in 2308 days


08-16-2010 02:58 PM

Topic tags/keywords: jig help dovetail bit depth

Greetings, all.

I believe I’ve done my due diligence in selecting this forum for my question, so please forgive if I’ve made the wrong choice.

I’m a moderately experienced builder in the midst of a problem I really never anticipated. I’m building a dresser for my daughter and am ready to build the drawers. I’ve set up my nice, new 4210 Porter Cable dovetailing jig, and have been trying (and failing) to use the supplied bit and template for half-blind dovetails.

I am building the drawers out of 1/2”-thick stock, and using the stock template, bit, and collar supplied by the manufacturer (17/32”, 7-degree, with the 3/4” collar). When I test my setup with some scrap 1/2” stock, I find myself having to adjust my bit depth to within 1/16” the thickness of the workpiece, which just seems entirely too deep to me. Even at that, the fit is not as snug as I would like, implying I might need to go to an even deeper bit depth, which at this point I think is not practical.

Obviously, as I’ve read numerous posts, articles, and reviews on this jig, and all seem to be favorable, I realize I’m doing something wrong. Its been a few years since I built dovetailed drawers, so I’m sure my skills are rusty. It would seem to me that the maximum expected bit depth for dovetailing 1/2” stock would be somewhere between 1/4” and 3/8”, but I’m well beyond that at this point – closer to 7/16” or more at this point.

If there are any suggestions or thoughts in the “hey, dummy, did you check this first”, I’d sure be appreciative.

Many thanks in advance,
SoonerDave “David”
Sweltering the in OKC heat :)


13 replies so far

View ajosephg's profile

ajosephg

1878 posts in 3029 days


#1 posted 08-16-2010 03:22 PM

I don’t see any obvious mistakes in your setup as described. If no one comes back with an answer, I’ll try to duplicate your setup this afternoon and see what the results are.

-- Joe

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SoonerDave

6 posts in 2308 days


#2 posted 08-16-2010 03:37 PM

That would be awesome, Joe, thanks!

As a sanity check, I took a look at the drawers I built for my desk about a decade ago, from similar 1/2” stock, and the dovetail depth was right-at 1/4”, which is what I expected for this project. However, I used a different jig for that effort, and the template I used was damaged….

Thanks again, Joe. Appreciate any help I can get!

David

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ajosephg

1878 posts in 3029 days


#3 posted 08-16-2010 04:05 PM

No problem, even though you gotta know it is going to stress me out giving aid and comfort to a Sooner – seeing as how I lived 26 years in NU territory and you – if you are going to survive in Nebraska you’d better be a Big Red fan! :)

-- Joe

View kerflesss's profile

kerflesss

182 posts in 2836 days


#4 posted 08-16-2010 04:18 PM

Hi David,
Like Joe said sounds like you’re doing it right but down load this

http://ip.podcast.tv/video-episodes/podcast-%2320-machine-cut-dovetails-4563260.html

and it may help out. The video is pretty long and involved so make some time.
Good luck.

Craig

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SoonerDave

6 posts in 2308 days


#5 posted 08-16-2010 04:50 PM

LOL Joe – yeah, been a Sooner just about all my life – hate losing you guys to the Big 10!!

Thanks for the help!!!

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ajosephg

1878 posts in 3029 days


#6 posted 08-16-2010 09:48 PM

OK – here’s the results.

I used the same template, router bit and template guide part numbers that you used.

I have never made half blind dovetails before, so the jig bit depth guide was still as received from the factory.

I used 1/2 inch (nominal) China birch plywood. Actual thickness is 0.442 inch.

I set the jig up as per pages 18 and 19 of the instruction book.

First pass resulted in pin depths of about 7/16 inch – but they were too tight to assemble, and the wall thickness of the plywood was super thin.

I decreased the depth (to make a more shallow cut) per page 19 and tried again. Almost good, but still too tight. After one more depth decrease I got an almost perfect fit, slightly loose. One more adjustment would nail it, but since both ends of the range were hit I called it quits.

At this point the pin depths measure 0.233.

Based on these findings it seems to me that you have something going on with the bit. Look at the bit and determine for sure that it is a genuine PC bit with the correct part number (43776) My bit has the Porter Cable logo on the first line and the second line reads 43776 PC A 0206

Someplace in the foggy recesses of my mind I seem to recall that only PC 7 degree bits work with their template. Maybe somebody swapped bits somewhere along the line.

Why don’t you throw your stuff into your Lear jet and pop over here for dinner and we’ll see how it works on my stuff.

-- Joe

View CyBorge's profile

CyBorge

79 posts in 2643 days


#7 posted 08-16-2010 10:23 PM

If you’ve got a pot of coffee and a dozen or so donuts on hand, you can spend some time reading through this thread. It was for the Porter Cable 4216, but I’m sure a lot of the content applies to the 4210. We went around and around in there, with a lot of people providing insight from all sorts of crazy angles. Joe especially went the extra mile trying to help that guy.

-- "How can I be lost if I've got nowhere to go?"

View SoonerDave's profile

SoonerDave

6 posts in 2308 days


#8 posted 08-16-2010 11:20 PM

Everyone,

Please accept my thanks for alll the good replies – and Joe, my goodness, thank you especially for all your detailed testing and assessment.

I’m not entirely sure what’s going on at my end, but after continuing to mess with this the most of the day (a day I had taken off to have these drawers FINISHED, argggh), I have a pretty strong suspect. First, I have to backtrack a bit.

The template collar supplied with the jig is intended for Porter Cable routers. I didn’t have a router that accepted a 1/2” shank bit, so I borrowed one from a buddy at work – only problem is that it’s a Craftsman router. Now, not ragging on the router, because its actually a very nice unit, but it won’t accept the PC template.

Soooo….I trotted down to Lowe’s and picked up a universal adapter base, called a “TurnLok” system that offers a replacement base that accepts a round, fitted, locking interior bushing of various sizes, or an adapter for threaded fittings like those from PC. Insert the bushing, rotate to lock, and go on your way. It looked reasonable, so, I picked one up, brought it home, attached it, got it centered, and thought we were good…

...Until I started looking really closely at the template locknut through the upper view port as I was routing one my last few thousand test pieces. It was only then I noticed that the the template bushing WAS SHIFTING LEFT AND RIGHT as I guided the router through the template fingers!!!! The deflection varied with the amount of force I used to move the router, meaning that no two sets of dovetails were identical, and the size of the sockets/pins could vary by what I would assess to be a minimum of 1/16” either (or both) directions.

So, after using the worst Yosemite Sam curse words I know, like “drat” and “dagnabbit,” I pulled the template out and manually “fidgeted” with the center adapter and realized I could shift it (even in its supposedly “locked” position) just between my thumb and forefinger. What a piece of junk!

Rather than fight the battle of router template adapters, I went back to Lowe’s and spotted a closeout on a PC combo fixed/plunge router for $125 and snapped it up. Hopefully this will directly accept the PC guide template, solve my problem, and give me a nice plunge router as a benefit.

I will set the new router up and perform some tests and post the results here.

Continued thanks, and I will update as soon as I have more info.

David

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ajosephg

1878 posts in 3029 days


#9 posted 08-16-2010 11:26 PM

Sounds like your on the right track!

-- Joe

View SoonerDave's profile

SoonerDave

6 posts in 2308 days


#10 posted 08-17-2010 03:21 PM

All

As promised, here is some update information regarding the problems I was having with the PC 4210 dovetailing jig.

It looks like my suspicions were correct. It appears the source of my problems was, indeed, the blasted Milescraft universal router adapter base.

After setting up the new combo fixed/plunge PC router I picked up, and got it set up with the template collar, I went back to the jig’s default depth settings and made a test cut. The result? I had a slighly loose joint on the first try. It took about twenty minutes of adjusting (micro-tweaking) to align the scribe line on the template properly to get the dovetails flush, and maybe 1/32” of adjustment in bit depth before everything was perfect. It was much more like the experiences I’ve seen and read with this jig.

While I didn’t plan to buy a new router for this project, looking back, I surely experienced more than $125 worth of aggravation in wasting a day all for the sake of a worthless $20 “universal” router adapter plate.

On the flip side, however, I did pick up a really nice combination router for about half its original price, and it looks like I’m ready to start cutting drawers. Here’s hoping!

The moral of the story: If you’re having trouble with this jig, and you’re not using a PC router, be sure whatever adapter you’re using keeps that template collar absolutely stable, or you’re sunk before you start!

Many, many thanks for all the good suggestions and help offered here. I doubt I’m anywhere near the experience level of most here, so I don’t know that I can return the favor, but I will certainly continue to lurk here and chime in if I can help. Special thanks to Joe for his trouble in setting up the jig and reporting his results here.

Again, many thanks.
David W, OKC

View intheshop's profile

intheshop

58 posts in 2306 days


#11 posted 08-18-2010 04:44 PM

I’ve had quite a bit of experience with this jig, as well as the new Omnijig. And you’re right, David, the template guide must be absolutely stable. One thing you can do to ensure this is to put an O-ring around the threaded side of the collar before you put the lock ring on. This helps isolate vibration and keeps the collar steady. And it also how the Omnijig is set up. In fact, I once forgot to put the lock ring on and the O-ring held the template guide in place perfectly.

It is important to use the supplied template guides – they aren’t standard sizes. But you don’t have to use a PC router. Most routers except for Bosch and some Craftsman routers will accept the PC template guides.

Happy Dovetailing.


Cole
Rydal, GA

-- Fast is fine, but accurate is final. The real trick is learning to take your time when you're in a hurry. - Wyatt Earp

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ajosephg

1878 posts in 3029 days


#12 posted 08-19-2010 04:50 AM

Cole’s comment reminded me of another thing to keep in mind when using template guides.

Probably the guide will not be centered relative to the router bit. I have 2 PC bases (plunge and fixed) and both were off center at least 5 thousands. When routing dovetails this is not a big deal – if you don’t turn the router body relative to the jig as you make the cuts. In other words if the router’s handles are in line with the jig on the left side, don’t let them deviate as you go across the work piece, or the dovetail spacing will not be uniform.

You can buy router base plates with holes machined to allow the base to be adjusted to align perfectly. What I did was to use a half inch brad point drill to make the tapered base holes flat, allowing the plate to be adjusted. (Also changed the mounting screws from flat head to binder head.)

-- Joe

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intheshop

58 posts in 2306 days


#13 posted 08-21-2010 05:59 PM

Good point, Joe. And a centering cone really comes in handy here.

And I should correct my earlier reply. You can use different router bits and template guides, it just changes the depth that will result in a proper fit.

-- Fast is fine, but accurate is final. The real trick is learning to take your time when you're in a hurry. - Wyatt Earp

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