# PC 4212 Bit Depth



## zach (Nov 16, 2009)

Hello everyone - sorry if my first post here is something that's been asked before. I did a quick search and didn't come up with anything so I figured I'd just ask. 

I just got a 4212 second-hand and after trying out the Jet jig and the PC 4112, I'm loving the build-quality and well-thought-out design of the 4212.

Given that this is a used unit, the bit depth guide for half-blind DTs is not at its factory setting, so I am not confident about the bit depths I'm trying. The manual simply instructs you to set the bit depth to the guage but in my case that is no help. Is there a standard depth setting I can start out with? 

I'm cutting half-blinds with the standard template, a PC 690 router, the stock 7 degree 17/32 bit, and using 1/2" baltic birch ply. I've gone through a LOT of stock trying to dial it in and it's just not quite good enough. I feel like I'm sort of chasing it since I don't know what the recommended bit depth setting should be. 

Anyone out there know what the factory depth setting on the 4212 is?

Thanks!


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## rwyoung (Aug 3, 2008)

I wouldn't even bother with the depth gauges. I have a 4212 and the just aren't that accurate.

Your best method is to use your workpieces as the gauge. 

Use a marking gauge to scribe a line on the workpiece at the depth you want. For a 1/2 blind, this would be about 3/4 the thickness. You can eyeball this or measure, both are equally valid.

With your workpiece installed in the jig, you can set the router into place and raise or lower the bit (a fixed base router works better for this task than a plunge base but both work) until the edge of the bit just catches in the bottom of the marking gauge groove. 

Depth set. Now route a test piece. Adjustments may be necessary but this is a pretty quick way to set depths.

One key thing about the jigs, they do assume all your workpieces are equal thickness. At least all the sides are the same thickness and all the faces are the same thickness (but a side doesn't have to be the same as a face). Oh, and another thing about the 4212, if your workpieces are narrow, less than 1/3 the width of the hold-down fence, I suggest you add a second dummy piece at the far end to keep things square. This also goes for setting the template height and depth. It is pretty easy to skew the template on this (and most similar) jigs.

Got all that? I don't have time tonight but if it would help I can try and take some pictures later this week.


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## Bob N (Oct 12, 2004)

Hi Zach, it looks like Rob has already loaded you up with great info so I will just say welcome to the forum.


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## zach (Nov 16, 2009)

Thanks fellas, for the welcome and the help. I'll give that a whirl this evening. I'm probably overthinking the whole thing, but my joints were 'getting there' but were too tight. So naturally I addressed that by making very gradual decreases in bit depth. I got to where the joint looked good, but the tails were just a bit deep. Once I started messing around w/the front-back placement of the template was when I really started having questions. It makes me wonder if the tightness is because of the template being too far forward rather than related to bit-depth.

Sigh - well, I'll get it. Thanks again - I'll let you know how it goes.


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## rwyoung (Aug 3, 2008)

For the 1/2 blind, cut in a single pass, it is the bit depth that sets the "tightness". Deeper cut = tighter joint.

The horizontal position of the jig sets how deep the side recesses into the front. A good starting point for that one is to have the scribed line on the jig centered on the joint between the top and side as they are clamped.

Bit depth and inset depth are separate adjustments on the jig.

There is a good video at Woodworking Online (a Woodsmith Store seminar) on using the PC4212. I think they cut full dovetails but lots of the same information applies and you can learn a lot by watching somebody use the jig.

I don't use mine every day so usually I have to re-read the manual (not always the clearest writing but so far I've found it to be correct) and run a few test pieces. Seriously, with their manual I've found that reading it out loud helps. Something about the act of reading out loud slows things down and can help comprehension. But then I don't have anybody in the shop to overhear me either...


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## jlord (Nov 16, 2009)

For 1/2 blind dovetails set you bit depth to 5/8" ( 1/4" for template & 3/8" for material = 5/8" total ) from the base plate of the router, that will get you real close to where you need to be. All your stock is run with the inside facing up in the jig. So the same setting will work with different thickness of material because you are always referencing from the inside of the joint. A real good online video to watch on this is from woodworking online com. Podcast # 20 Machine Cut Dovetails. He shows the PC jig doing 1/2 blind dovetails and shows how to set your router up.


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## jlord (Nov 16, 2009)

Zach, also the PC jig uses 1" spacing. So to end up with 1/2 tails on the top & bottom of joint to be centered, your material sizing needs to be in 1" increments + 1/4" ( 1-1/4" 2-1/4" 3-1/4" 4-1/4" ect ). Use the recommended Template guide 3/4" O.D. #42040 & Dovetail bit 17/32" - 7 degree # 43776PC for this jig. Hope this helps.

Here is an example picture. 
This drawer is 4-1/4"H the next size up would be 5-1/4"H. That would be to tall because the opening is 5". These drawers have under mount soft close slides & the top of the drawer has 1/4" clearance from the top of the opening when installed. There is a 1/4" dado located 1/2" up from the bottom edge for the drawer bottom, which centers it on the tails & pins + clearance for the under mount slides.


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## jlord (Nov 16, 2009)

Zach, I forgot to mention in above post that with the half blind template both joints are machined at the same time. When you have your setting, lay out your pieces & number each joint & label the top or the bottom so they stay together. Fronts & backs are horazontal on top of the jig with inside facing up. Sides are verticle with inside facing out towards you. 

For a drawer I number my corners 1,2,3,4 & mark b for bottom on inside of all pieces. Even number joints are done on one side of jig with bottoms against stops, inside facing up & odd number joints done one other side of jig with bottoms against stops inside facing up. You will route both sides of joint at same time.


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## sprior (Nov 17, 2009)

Having just recently purchased a new 4212 (but don't assume the depth gauges are set right) and still new at using it, I decided to upgrade the depth stop screws. I figure those plastic topped thumbscrews aren't going to be flat or precise so I replaced them with brass flat head screws (size 10-32). I still found that the screw heads do not come out flat to the template, but I think it'll be a bit better. I set their depth with a 3/8" brass set up block. Haven't actually tried any dovetails since to see if any of this helped.


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## jlord (Nov 16, 2009)

I just noticed if you scroll down to Tools & Woodworking on this forum in the sticky section will be Woodsmith Videos. You can open the pdf & click on podcast # 20 to watch the PC jig & router being setup. You can also save the pdf on your computer to watch anytime.


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