Thread: Having trouble...

before you get to the stage of throwing it into the bin, can you place it back in is packaging and post it to me.

Bit hard to answer Ivor, could be a number of reasons.

You mentioned jig square to the table, table flat, height correct.

Is your timber cut exactly square? No warp or twist? Could the workpiece be slipping slightly on the right angle fixture? Router bit securely in the collet, and plunge locked solid?

Put up a couple of pics & we'll see what other gems of wisdom we can come up with

HTH

Cheers................Sean

Okay photos.

Here's the full size box measures about 100 x 100 x 200mm. The gaps are on the far right top and on the near left corners. All other dovetails seem okay. Photos of the gaps (slightly blurred) follow.

photo of gap in far right corner,about 1 mm wide

another showing the next dovetail down as well

gap front left second dovetail down

Is your router locked down? Are the bits tight in the collet?

The gaps look a bit staggered, like the router or bits are moving

Gday Ivor, appears that the issue is cutting depth of the d/tails. My guess is the workpiece is slipping in the right angle fixture at some point.

Otherwise, look at everything that affects depth of cut - Router: does the plunge lock securely, is the collet clean, within tolerance & not slipping, any end float on the router shaft, bearings OK, is the router securely attached to the table insert with no play, router bit good quality & sharp.

Right angle fixture - is it sliding smoothly without riding up, no horizontal or vertical slop, workpieces clamped securely to fixture (decent G clamps are best).

Incra fence - secured to table, locked down, no slop anywhere, no flex in the fence when moderate pressure applied to R/A fixture, racks screwed down properly

Timber - straight & square

Check all of these for any problems, look for the simplest causes first, if all of these are OK I can't see why one cut would be different to the next.

Good luck...............cheers...............Sean

Originally Posted by scooter

, router bit good quality & sharp. n

My guess is that the router bit may be a problem, and the way you are clamping the timber could also be an issue. It might not be dead square.

Send a PM to DPB. He should have a look at this.

I had a first hand look at his new box with Incra Double dovetails today and it was perfect. It's not the jig.
DON'T THROW IT AWAY.

Were these the last cuts made? If so, I'd strongly suspect collet slippage. These bits are notorious for trying to climb out of the collet, because of the angled cut. Even straight spiral bits can be troublesome in this area.

Joe

First I'd look at what Gumby and scooter said. Then say what model router and bit you are using (please don't say Ozito).

We can only go by most likely culprits and I've got to say that the Incra is not really amongst them.

I'd also be looking for a gob of sawdust that may put it out of square when clamped or maybe it is not of even thickness.

My personal guess is you may be using a collet that is slipping, you have some end float in the router or the bit is slipping. Please let us know if you are using a collet with 1/4" shank bits. If using a Makita D handle router then you really need to check the collet and collet adaptor for a tight fit.

One more thing, Australian metric router collet with American Imperial bit, each at opposite ends of the tolerance spectrum (within limits but in either direction) can give you a problem. Another collet may fix the issue.

See all the above. Hope you are locking the plunge on your router, and it is secured solidly to the table. If occasionally you rush a cut, loading up the router (and bit), you might be getting movement.

Course, if you want to bin it.....I am happy to PM you an address to dispose of it to.....

Ivor, I'm relatively new to the Incra system. I have an Incra Ultra Lite and use a Triton router in my table.

I agree that the problem appears to be with the depth of cut. But I don't think it is that your collet is slipping allowing the bit to climb out of the collet. If it was, I think that would soon become apparent to you.

Assuming that the timber is cut squarely, it looks to me that the excessive gap is caused by your piece not being clamped correctly in your right angle fixture. This may be caused by your fence not being absolutely square to the table. [Of course you can eliminate this concern by shimming the fence so that it is.]

When you press the work piece against the fence, if the angle of the fence to the table is greater than 90 degrees, even slightly, it will cause the piece to lift off the table on the side away from the fence thus causing the cut to be deeper on the right side than on the left side of the piece. If it is less than 90 degrees then it will lift on the side closest to the table causing the cut to be deeper on the left side of the work piece.

The operating instructions state that you should just touch the piece against the fence but make sure that the base of the piece is on the table. If, when you tighten the clamp, you place too much pressure against the timber so that it registers to the fence rather than the table you will get the result you are getting.

Make sure that you are using parallel clamps. These place clamping pressure over a larger surface of the work piece.

This is A close-up of a box I posted here http://urlzip.org/Inra_Double_Dovetail

As an 'interpid Tritoneer' (thanks George) I suggest that one possible cause of the problem is inconsistant pressure being applied by the operator - this is a pretty constant feature of Triton woodworkers, specially with the mitre gauge on the 2000. If you lean on the sled you will get varying pressure and this will bend the whole jig a fraction - and as you go along you will vary, even if just from fatigue.

This is also seen as a problem in competitive archery, and the solution suggested there is - use the least force possible to hold (or in this case, move) the item, without dropping it.