Perfect Half Blind Dovetail joints on Porter Cable 4200 jig

[David Tolsky]

Hi, I'm a newbie to this jig. I'm getting close but I'm not getting perfect half blind dovetail joints. I bought the jig second hand at an estate sale and it is in great shape. Came in it's own wooden case, pretty slick. I believe I've followed directions well from the manual and you tube videos. I'm a little sketchy on the router bit depth. How do I know that the bit depth gauge on the jig is set correctly? I know that deep depth is tighter and shallow is looser. I'm at the point where the tails fit into the pins more than halfway but do not insert fully into the pins. Do I need to keep fine tuning the bit depth on the router into micro-moves until I nail it or is there a template adjustment that can help me? Thanks for your time.

[Doug Hepler]

David,

In my experience the full-size (1/2") half-blind setup is somewhat forgiving and so I advise that you just keep playing with the depth until you get a good fit. I do not know of any tricks or setups for adjusting the fit that are not in the manual. Maybe I was lucky, but I just set the depth to a bit more than half of the pinboard thickness and got good results the first try.

I was never able to get good results with half-blind DT using the miniature template and bit, however. I eventually finished that job by manually trimming the tails.

Doug

[Earl McLain]

I've had the best luck by marking the depth on my stock, mounting it and then setting bit depth to that--stopped using the depth gauge.

Another thought is to check the bushing diameter to make sue it's not a little undersized (or over?) and that it's centered to the bit.
Earl

[George Bokros]

Centering the bushing is critical. There is an additional manual available on line. If you cannot find it PM me and I will scan mine and email it to you.

[Ted Baxter]

David check out Kings Fine Woodworking youtube channel he uses this jig a lot and goes into detail on how to set it up and use it.here is one of his videos that might be helpful "PurpleHeart Keepsake Box part II" https://www.youtube.com/watch?v=cWFMqX-7kK (https://www.youtube.com/watch?v=cWFMqX-7kKs) I have never attempted dovetails but plan on learning to if the future and his videos are always interesting and instructive. Good luck

[Pat Barry]

Centering the bushing is critical. There is an additional manual available on line. If you cannot find it PM me and I will scan mine and email it to you.
I agree that getting the bit centered is important, to a degree, but I found that as long as I was always holding the router the same way (not rotating it from cut to cut) the joint alignment was fine. I never trusted the indicator lines - always just used those as a gross adjustment. If you want perfect results you need to iterate through the process of tweaking the various adjustments until you get what you want. (note - make sure that your setup material is milled to the same thickness as you real material or there will be fitup problems.)

[Jim Becker]

Bit depth is simple but not simple...you have to sneak up on it and the final adjustments are the equivalent of that "proverbial hair", but you start "at the line" of material thickness. The only want to do this is to have additional material that is exactly the same as you'll be using for your project so you can do multiple test cuts to zero in on "perfection"...or at least as close as it will be to that in the end. Your test material should also be the same species so that it exactly matches what will come on the real deal.

Pat's comment about not varying the position of the router is also important. There will alway be slight variances in the roundness of the guide bushing and even with careful centering using appropriate tooling, it's near impossible to get that perfect once you start tightening baseplate screws. So holding the router exactly the same through the entire cuts is important.

I also find that a fixed base router is much more effective (and less top heavy) for cutting dovetails on a jig than a plunge router is. Easier to adjust depth granularly, too.

[Doug Hepler]

Here is a link to the supplemental manual: www.portercable.com/jigs/dovetail/SupplementalManual.pdf (http://www.portercable.com/jigs/dovetail/SupplementalManual.pdf)

[David Tolsky]

Centering the bushing is critical. There is an additional manual available on line. If you cannot find it PM me and I will scan mine and email it to you.

Thanks George,

The bushing only screws on one way to the router or am I missing something? How would I adjust the bushing to center it?

[David Tolsky]

David check out Kings Fine Woodworking youtube channel he uses this jig a lot and goes into detail on how to set it up and use it.here is one of his videos that might be helpful "PurpleHeart Keepsake Box part II" https://www.youtube.com/watch?v=cWFMqX-7kK (https://www.youtube.com/watch?v=cWFMqX-7kKs) I have never attempted dovetails but plan on learning to if the future and his videos are always interesting and instructive. Good luck

Thanks Ted, I will check it out :)

[David Tolsky]

Thanks Jim,

This is a special order box I'm working on and I've decided to challenge myself on these dovetails. The materials are a combination of Brazillian cherry, ash and walnut as a glue-up. The challenge is to get as perfect a dovetail joint so with the box pieces are assembled, the stripes of different wood species will line up correctly and be uniform around the entire box. Not quite feasible to use the same species as practice wood as the wood is expensive and hard to come by. I've been using oak, planed down to the same thickness to practice the cuts. I have the combination plunge/fixed base Porter Cable router so I don't use the plunge base. Thank you all for your suggestions.

[David Tolsky]

I downloaded it, thanks!

[Cary Falk]

Thanks George,

The bushing only screws on one way to the router or am I missing something? How would I adjust the bushing to center it?

There is some wiggle room with the base plate of the router. Loosen up the 3 or 4 screws on the plate to center the bushing.

[David Tolsky]

There is some wiggle room with the base plate of the router. Loosen up the 3 or 4 screws on the plate to center the bushing.


Will do, thank you!

[Jim Becker]

Thanks Jim,

This is a special order box I'm working on and I've decided to challenge myself on these dovetails. The materials are a combination of Brazillian cherry, ash and walnut as a glue-up. The challenge is to get as perfect a dovetail joint so with the box pieces are assembled, the stripes of different wood species will line up correctly and be uniform around the entire box. Not quite feasible to use the same species as practice wood as the wood is expensive and hard to come by. I've been using oak, planed down to the same thickness to practice the cuts. I have the combination plunge/fixed base Porter Cable router so I don't use the plunge base. Thank you all for your suggestions.

SO....you're starting out with a, um...simple...project, eh?? :D

[Leo Graywacz]

I always use a plunge router for dovetails. That way I can use the plunge stop adjustment to adjust by the thickness of a pc of paper. The fit should be more than snug, but not to tight. You should be able to bang the joint together with a hammer and it should stay tight. Put a bit of glue in there and bang them together. In a few minutes you can start sanding the box.

[George Bokros]

To center the sub base you need a centering cone or a centering pin that fits the bushing.

[Mike Cutler]

Hi, I'm a newbie to this jig. I'm getting close but I'm not getting perfect half blind dovetail joints. I bought the jig second hand at an estate sale and it is in great shape. Came in it's own wooden case, pretty slick. I believe I've followed directions well from the manual and you tube videos. I'm a little sketchy on the router bit depth. How do I know that the bit depth gauge on the jig is set correctly? I know that deep depth is tighter and shallow is looser. I'm at the point where the tails fit into the pins more than halfway but do not insert fully into the pins. Do I need to keep fine tuning the bit depth on the router into micro-moves until I nail it or is there a template adjustment that can help me? Thanks for your time.

David

I have the same jig, as do many others, and it really is a nice jig for dove tails.

You need to get that supplemental manual. It contains a lot of info not covered in the manual that came with the jig. Why it's not part of the manual is beyond me???:confused:

Make sure that the pressure bar is putting even pressure across the material holding it in place. If you have a relatively narrow piece, you may need to put a second piece of the exact same thickness under the pressure bars.

Right now it sounds as if your jig has to move the tail section forward to narrow the tails. Trying to use the reference markers on the jig is a good way to get close, but I have mine etched. Being off a pencil line's width is enough to throw things off. Use a depth gauge, or the tail of a vernier caliper, to make your jig adjustments. This way you can keep track of how you have been adjusting it, and know that both ends of the jig are in the same plane.

Be absolutely certain that the reference stops are square to the material, not the jig.

Porter Cable makes a centering cone for their bushings. Use the PC Brass, or equivalent brass bushings. I found that the aluminum types had a tendency to loosen up and I could not get them to stay in place as well. There used to be some made of stainless steel, but I forgot who made them, or if their still available.

Next time I do DT's with mine, I'm going to find a second jig also. I use dedicated routers, but it would be nice to have a dedicated jig for each.

It is a trial and error for that final fit. Any change at all and you end up starting over again. When I cut them, I don't touch anything until I'm done.

PS.

Brazilian Cherry, or Jatoba, is very unforgiving. It has to be exact, because it machines like mild aluminum. You will not force a Jatoba joint, or rely on crushing wood fibers, for a "tight fit" with Jatoba. I've used it a lot through the years and you have to work it to almost metal tolerances. It's beautiful when finished, absolutely stunning, but you have to be exact with it.

[Doug Hepler]

Great post, Mike Cutler.

Doug

[David Tolsky]

David

I have the same jig, as do many others, and it really is a nice jig for dove tails.

You need to get that supplemental manual. It contains a lot of info not covered in the manual that came with the jig. Why it's not part of the manual is beyond me???:confused:

Make sure that the pressure bar is putting even pressure across the material holding it in place. If you have a relatively narrow piece, you may need to put a second piece of the exact same thickness under the pressure bars.

Right now it sounds as if your jig has to move the tail section forward to narrow the tails. Trying to use the reference markers on the jig is a good way to get close, but I have mine etched. Being off a pencil line's width is enough to throw things off. Use a depth gauge, or the tail of a vernier caliper, to make your jig adjustments. This way you can keep track of how you have been adjusting it, and know that both ends of the jig are in the same plane.

Be absolutely certain that the reference stops are square to the material, not the jig.

Porter Cable makes a centering cone for their bushings. Use the PC Brass, or equivalent brass bushings. I found that the aluminum types had a tendency to loosen up and I could not get them to stay in place as well. There used to be some made of stainless steel, but I forgot who made them, or if their still available.

Next time I do DT's with mine, I'm going to find a second jig also. I use dedicated routers, but it would be nice to have a dedicated jig for each.

It is a trial and error for that final fit. Any change at all and you end up starting over again. When I cut them, I don't touch anything until I'm done.

PS.

Brazilian Cherry, or Jatoba, is very unforgiving. It has to be exact, because it machines like mild aluminum. You will not force a Jatoba joint, or rely on crushing wood fibers, for a "tight fit" with Jatoba. I've used it a lot through the years and you have to work it to almost metal tolerances. It's beautiful when finished, absolutely stunning, but you have to be exact with it.

Great post! Sorry it took me so long to answer this...So I cut the dovetails and they turned out pretty good. HOWEVER, :) it seems I've run out of real estate on the jig template. I cut with the router from right to left and my pin boards turned out half a pin short. I literally had to re-allign the pin board away from the far left edge so that I could cut half a pin all the way at the left end. Weird. Is this because of an odd-sized board width? Anyway, after I did this, all was well.

[Jim Becker]

A fixed template dovetail jig is naturally going to prefer certain dimensions for the joinery it creates...odd sizes can indeed make for spacing challenges. The instructions for your jig should provide guidance on that.

[Mike Cutler]

David

Yes, if your board is an "odd" width, it may not line up really well. You might have been able to align a spacer piece to get the pins evenly spaced, but maybe not.
The Leigh Jig is capable of any width, as long as it fits into the jig. The PC is kind of stuck with some basic "math options". This is one of the reasons folks opt for the Leigh, because of it's variability in setting pins.
The supplemental manual details cutting from the left and right hand side of the jig, which may have helped you out. You start on one side and finish on the other.
It's a good little jig, but it does have it's limitations. ;)

[Steve Eure]

WWGOA has a complete tutorial on their website. Goes into great detail on this jig. I don't know if you can view without being a member, but if you can, it is well worth the time watching. Helped me tremendously.

[Doug Hepler]

David,

Somehow, the instructions for jigs often lead the user down the path to setting up the jig instead of laying out the workpiece. Yours is a common problem. For example, just suppose that you were going to cut those DT by hand. You surely would have noticed that a series of 1/2" pins and 1/2" tails would not come out "even" on your boards. I'm just trying to make the point that our primary focus should always be on the work rather than the tool. It's true that the fixed width is a shortcoming of the PC4200 series jigs, but you can usually work around that if you lay out your work first.

Also, as you gain more experience with this jig, you will discover the need to establish and maintain a reference edge (RE) on every board. That will no doubt lead you to see that sometimes you cannot flip the pin board (e.g., when cutting through DT) but rather need to set up both the left and the right offset guides exactly the same so that the RE is always registered against an offset.

I wrote up some notes about using this jig. If you PM me your email address I will be happy to send them to you.

Doug

[David Tolsky]

David,

Somehow, the instructions for jigs often lead the user down the path to setting up the jig instead of laying out the workpiece. Yours is a common problem. For example, just suppose that you were going to cut those DT by hand. You surely would have noticed that a series of 1/2" pins and 1/2" tails would not come out "even" on your boards. I'm just trying to make the point that our primary focus should always be on the work rather than the tool. It's true that the fixed width is a shortcoming of the PC4200 series jigs, but you can usually work around that if you lay out your work first.

Also, as you gain more experience with this jig, you will discover the need to establish and maintain a reference edge (RE) on every board. That will no doubt lead you to see that sometimes you cannot flip the pin board (e.g., when cutting through DT) but rather need to set up both the left and the right offset guides exactly the same so that the RE is always registered against an offset.

I wrote up some notes about using this jig. If you PM me your email address I will be happy to send them to you.

Doug


This is a super old post but if you still have those notes on using the jig I'd love to see them.

[Jim Dwight]

I am unfamiliar with that jig but I like a purpose built U-shaped wooden jig with a drywall screw in it for bit depth. The legs of the U straddle the bit and the screw just touches with the bit at the right depth. It is really nice to be able to raise the router up to the height you can see it when checking.

My other comment, hopefully useful, is to leave pieces long when you start to cut joints. If you have an extra inch or two, you can cut a joint or two or three and trim them off it they are not OK. If they are, you can cut to length then.

I use a cheap Harbor Freight jig with a Grizzly 7/16 template ( makes drawers in 7/8 increments so 1 3/4, 2 5/8, 3 1/2, etc) which I leave set up on a stand that provides extra support to the work pieces and has a drawer for setup jigs in a drawer. I keep a correctly cut joint or two in there and pieces with lines for where the cuts go for setting the side stops.

Dovetails are a quick and easy way to make nice looking and strong drawers (and boxes) but the quick to doing them quickly is to not spend all day on setting up the router and jig.