Leigh D4R Pro

[Derek Arita]

Not that anyone is asking, but my feeling is, use one router to work out all the bugs and learn the jig. Once you're able to produce repeatable, "perfect" joints, then you can introduce a second router, keeping in mind that every router will have specific differences and tolerances and will produce slightly different results. At that point, you can make the necessary adjustments to the second router, to get it to perform as exactly like the first, as possible.

[Will Blick]

Plywood is not for dovetailing, especially not the common plywood. I have had success using top quality Baltic Birch plywood, but even that will sometimes delaminate and chip out when trying to cut dovetails. When I want to cut a strong joint in Baltic Birch plywood I now use an Incra I-Box jig and a Freud SBOX8 blade set on my Unisaw. It makes great box joints in Baltic Birch plywood with only very rarely a chip out. Attached are a couple of photos of my Baltic Birch box joints.

Charley

Charles, very nice chests, great box joints...
thx for sharing...
I am curious, other than using Ply, is there any other benefits of using an IBox over the D4R?
it looks like an excellent designed jig, but its another tool to buy, store, etc.
Your input would be helpful, thx in advance.

[Derek Arita]

Using HD 1/4" Birch Ply and the Leigh box joint setup, I was able to make clean box joints. Practicing my routing technique prior to the real thing, made all the difference. If I can do it, anyone can.
IMG_1009.jpg

[Will Blick]

Nice... Leigh would be proud of that pix!
> If I can do it, anyone can. lol
Would doing an initial clean pass with a larger router bushing, then a 2nd pass with the right size bushing.... maybe helpful to insure no tear out? Yes, a bit more time consuming.

I have had such mixed results with ply over the years. At times, when the outer most laminates are not thick enough, it will splinter, even with the best circ. saw blades, festool rail system, my PM2k TS, etc. OTOH, with some really "thick ply" plywood, I never had these problems. So my guess is, part of the variable here is the quality of the ply, mainly how thick is the outer most laminates.

[Derek Arita]

Nice... Leigh would be proud of that pix!
> If I can do it, anyone can. lol
Would doing an initial clean pass with a larger router bushing, then a 2nd pass with the right size bushing.... maybe helpful to insure no tear out? Yes, a bit more time consuming.

I have had such mixed results with ply over the years. At times, when the outer most laminates are not thick enough, it will splinter, even with the best circ. saw blades, festool rail system, my PM2k TS, etc. OTOH, with some really "thick ply" plywood, I never had these problems. So my guess is, part of the variable here is the quality of the ply, mainly how thick is the outer most laminates.

Don't want to hi-jack the thread, but I will say that this was very thin and cheap ply. As I recall, a very lite pass across the front, between the fingers was needed. Also, it was crucial as to whether I plunged into the right or left side, from front to back, along with a lite pass across the back, between the fingers.

[Charles Lent]

Charles, very nice chests, great box joints...
thx for sharing...
I am curious, other than using Ply, is there any other benefits of using an IBox over the D4R?
it looks like an excellent designed jig, but its another tool to buy, store, etc.
Your input would be helpful, thx in advance.

I tend to like using box joints when the project needs to be strong and completed quickly. They are easy to set up for and make when using my I-Box jig. I mostly use it for making tool boxes, tote bins, etc. for my shop where I'm primarily interested in strength over beauty. I use the dovetail joints when making better quality furniture and fancy boxes. I'm not very good at cutting dovetail joints by hand, and it takes me nearly forever, so the Leigh D4R gets me great fitting dovetail joints in less than what seems like a light year of time, but I don't use my D4R enough to stay proficient at it, so setup usually takes quite a bit of time because I have to refresh my memory using the manual. If I decide to make box joints and will be using the same setup that I used the last time that I used my I-Box jig, I can take it out of the box and place it on my Unisaw, change the blade to the Freud box joint blade set with the same blade width as I had previously used, and begin cutting box joints with no setup required, other than setting the blade height for the thickness of material that will be cut. Once I have this right, I move the sacrificial strip in the I-Box jig to a new unused position and begin cutting my box joints. The I-Box jig does not get out of adjustment or need any re-calibration between uses, as long as I want the same width box joints again. I never tried avoiding the set up steps like this with my D4R, but I suspect that it will be the same, except for the time and trouble getting the routers and bits set up correctly, but I rarely cut dovetails of the same length and would likely need to change the jig to get half pins on the ends due to different length joints.

I don't cut dovetails in plywood, nor do I use my I-Box jig on a router table, because I have found that I get more chip out and de-lamination than I want. A router bit cuts when being fed in both directions while trying to cut box joints with it, requiring the use of a sacrificial strip on both sides of the work to keep chip-out to a minimum. The I-Box jig only has provision for one sacrificial strip on the saw blade or bit exit side. When cutting dovetails you are making cuts that are usually wider than the bit. If you closely watch the cutting action on Leigh's videos you will see how they move the bit, making cuts to remove the wood that would chip out easily, before going back and forth to cut the bulk of the material to be removed for each dovetail. Since box joints are usually the width of the router bit, this method is not possible and requires sacrificial strips to protect the edges of the work piece as the bit breaks through the sides of the board.

In my list of tips for using the D4R I neglected to tell you to wax both the top of the D4R and the bases of your routers, as suggested by another poster. Do this before you start using the D4R and you will be able to move the router across the jig much easier. Just make certain that the wax does not contain any silicone. Johnson's Paste Wax is my choice for wood shop use. Waxes containing silicone, like most car waxes, are banned from my wood shop, because the silicone causes all kinds of staining and finishing problems if/when it gets on the wood, and removing it once there is nearly impossible.


Charley