First Incra Joint

[Steven Bolton]

I cut my first half blind dovetail this evening on my Incra Ultra jig. The joints fit snug, but there are gaps as I hope the attachment reveals. How do I get rid of these gaps?

Any ideas?

Thanks

sb

[Bob Potter]

I cut my first half blind dovetail this evening on my Incra Ultra jig. The joints fit snug, but there are gaps as I hope the attachment reveals. How do I get rid of these gaps?

Any ideas?

Thanks

sb
Steve
It looks like from the picture that maybe you could raise the bit just a faction. Also clamping will sometimes pull the joints tighter. And maybe you've done this already. Keep at it and you will get them better each time.

Bob

[BARRY RESNICK]

Heighten to tighten; lower to loosen.

[glenn bradley]

I'm with Barry; higher-tighter / lower-looser. This refers to bit height in the way that we think of bit height on routers; that is, when we say higher, we mean extending further out of the router regardless of the routers orientation to gravity ;-)

The inconsistent gaps on the different pins looks like warped material. Did you square mill the lumber or is that just 1-by scrap that was handy? If the material was milled flat and square your gaps should all be the same unless something is moving during the cuts that shouldn't be(?).

[Jeff Kahan]

Your gaps seem somewhat irregular in placement -- they're not all at the tops of the tails -- which suggests something other than just bit height. Certainly raising the bit height will tighten things up, but it may make irregularities generated by the flatness of the pin board and the router table into joints that simply can't be put together. I have found that when cutting tails on my Jointech, it pays to only move the board from the plate to the cutter. If I start from the router table surface itself, I am courting trouble, because there is a slight dip in the table just ahead of the plate that makes leveling the whole system a fool's errand. (And, yes, replacing the table is on the long list of to dos.) In any event, the seemingly imperceptible movement of the boards from one plane to another (1/128"?) will throw off the cut -- minutely in your hand, but enormously when fitting the joint. Of course, if there's any crown or deflection in your plate, especially as you go over the insert rings, that will cause the same issues. Do what you can to find the the flattest surface for the board to traverse, and move it through as short a distance as you can get away with. This may limit gang cutting, to a few stacked boards, but it beats remaking half your drawers when they twist.

As to the pin board, any cup or twist will make for an ill-fitting joint -- and those problems are magnified by crowning or other defects on the router table. Here, brute strength can overcome some of the issues -- push down any area of the board that's trying to float above the cutter. Better still, mill 'em flat and cut 'em quick.

[Keith Cope]

Steve,

Look too at the tail board-check for squareness there. It has also been my experience that not all router bits are created equal--and that is something that will quickly manifest itself when using the incra.

Good luck,
Keith

[Bill White]

What bit shank diameter are ya usin? I found that I would get some flex with 1/4" shank dovetail bits. I think the big prob is the need for flat and square boards.
Bill

[David Duke]

I'm with all the rest either you're getting movement somewhere or the stock is not milled square/flat, that along with what Bill W. said, get 1/2" shank bits to help eliminate bit chatter.

[David Giles]

It looks like a warped board problem. But double check that the Incra scale and hairline match up exactly. Then stand directly over it and wear glasses (if you are at that age). It's easy to miss the mark by 1/32" either way.

Here's my first Incra joint (and first WW project). You can see the same problems with warped boards and misaligned joints. Your joint looks much better!

[JayStPeter]

Definitely looks to be a flat/square problem. The problem is either with your router table or stock. Check both.
For the table, make sure the table surface (including insert) is flat. Also check the fence and sled for square to the table and each other. Shim as required. I also find it helpful to clamp the material to the sled on the insert instead of the table. I know my insert is extremely flat. If you have a Rousseau insert, you might have a permanent problem until you rebuild your top DAMHIKT.
You also need to be careful with paralax when looking through the cursor. Make sure your head/eye is in the same position each time you lock down the fence for the next cut. An easy way to prevent this is to scratch a line on the opposite side of the clear plastic from the one that is there and make sure they align above the mark each time. If you see both lines, you'll be off by a 32nd on that cut.

Jay

[Bill Ragland]

I had this problem and finally determined that it was the router table insert. Most of the phenolic plates are made with a slight upward bulge to compensate for the weight of the router pulling down on the plate. The plate that I had still had a bulge after the router was installed so the edge of the board would never be flat against the table so the dovetails were always uneven. Actually the problem was the little rings that go into the insert for different diameter bits. None of the 3 inserts were flat.

I replaced the router table with a solid piece of MDF covered with laminate, drilled a hole for the bit and the problem no longer existed.

Quick test. With the router off and bit lowered below the table, take a flat, square piece of wood, stand it on end with the edge against the fence and pass it over the opening for the bit. Look for any light under the wood on either side of the piece as it moves over the bit opening.

[Bert Johansen]

I, too, had a problem with the similar JoinTech system until I checked the fence and determined it wasn't square to the table. Shims fixed the problem. As Jay says, check all surfaces for square.

[Bill Wyko]

When using an Incra, it's critical that the pieces are always placed against the fence on the same side. You will want to do a 180 with your work but you can't. You have to do a pull cut. Be careful, that is dangerous, use feather boards. As far as gaps go, thats adjusted by raising or lowering the bit until you get it right. If I rember correctly "heighten to tighten, lower to loosen" I also recommend trying with scrap of the same material you are building with. Good luck.

[Jim O'Dell]

I will say that your first one looks better than my first one! Mine were set at the right depth, but I was using the wrong bit (only one I had) for a through DT, so the finger width didn't match. Half blind it would have been fine. Jim.

[John Lucas]

In that the gap is slight and irregular, I would look at your vertical sled fixture. It it isnt locked and the pieces of wood clamped tight, it canj squiggle enough to give you this.
Here is a wuicj step bystep:
1) slide the vertical fixture to the rail and adjust the 2 white screws on the outside ...adjust them until they allow the fixture to move but barely, then lock down the middle screw.
2) place the pieces to route, in front of the v. fixture and there edges flat on the table...not flat againstthe fence. Push the pack against the fence but add the wood clamp when all the pieces are flat on the table...there may be a slight gap at the top of the pack against the fence.
3) when you move the v. ficxture back and forth, use your right hand to push the fixture down and forward over the cutter and your left hand just keeping the fixture down on the table...dont worry about against the fence.

if you pay attention to this, you willl get more uniform DTs with the Incra.

[Bill Wyko]

Your incra came with some small teflon shims. They are easy to loose in the box so you need to look closly for them. It's important to square your fence to your table. This will help in addition to the info above. Post more pics as you get better please.:)

[Tom Cowie]

Steven

I use the Leigh jig and I remember my first try at dovetails and it wasn't that good. Small changes make all the difference.

Tom

[Brandon Shew]

The inconsistent gaps on the different pins looks like warped material. Did you square mill the lumber or is that just 1-by scrap that was handy? If the material was milled flat and square your gaps should all be the same unless something is moving during the cuts that shouldn't be(?).

Ding!

In a 1/2 blind configuration on the Incra, you shouldn't have to lower or raise the bit to adjust fit.

I'm guessing either your stock is warped/not perfectly straight, or you aren't holding it steady enough, or your router isn't holding the proper bit position.

[Scott Rollins]

Lot's of good info here. I would look at the right angle sled first. It looks Like it was moving around a little on you during the cut. I find it best to tighten the nylon screws quite tightly and hold down firmly on the sled to keep it against the table. When clamping the board to the sled make sure it does not lift after loosening the center nylon lock screw.
Crowned router plates will not work with the incra. Get a aluminum plate from Rockler (cheap and pretty good) or no plate.

Flat square stock is a must.

[Steven Bolton]

Last night I had time to cut one half blind dovetail on my new Incra Ultra Lite. I appreciate the comments I received on that.

Tonight I tried it again. My main complaint this time is that the joint doesn't fit snug. I think this can be cured by raising the bit a little.

Overall, the joint is cleaner looking with more uniform gaps.

Last night, when I cut the tails, I only used my hand instead of a clamp. Using the clamp makes a big difference.

Any comments welcome.

sb

[Steven Bolton]

I agree that the sled was not tight enough against the fence. Also, it is important to take the time to clamp the wood to the sled. I just held it there last night.

John Lucas raises an interesting concept, about putting the wood down against the table and pay less attention to the fence.

I have a rockler with an aluminum plate. A black insert sticks up enough to cause a difference. I may just try removing it.

I think if I do a few a night and study them I will learn.

Thanks

sb

[John Lucas]

Steve,
Last nights DT looks very good...I mean VERY good. You are so very close. Someone mentioned squaring the fence. My suggestion is to pass on that for now. The fence being slightly off was by design...for a good reason. If you have it perfectly square and push the wood against the fence and slide, you may not have wood contact on the table...and that is where it counts. Incra added the shims so that users could shim if they insisted. MY TS-III is the only Incra fence shimmed and square. All of my other Incras (4) are slightly off, as the extrusion makes it.
Incra shows the use of a wood furniture clamp to hold the workpieces on the vertical fixture. I use the Bessey hand clamp.