Wood slipping on mitre gauge on router table

Kicked Back · 24 Jan 2023

I have a T-slot cutter and want to put a grid-like pattern of t-slots on a piece of MDF for jig making reasons. For the shorter axis I'm using a mitre gauge rather than the fence to 'crosscut' the channels into the MDF. However, the rotational force of the cutter causes the MDF to get pulled along the mitre gauge, giving a diagonal cut...

When holding the piece tightly against the mitre gauge, this was huge (I could see it moving, and gave like a 70 degree cut instead of 90. So I clamped the MDF to the mitre gauge fence and this was far closer to 90 degrees, but there was still slippage. Measuring with calipers it still drifted around 2mm out of square, and putting a straight edge along the channel you can see it looks a bit wonky too.

I've never used a mitre gauge on a router table before and this caught me totally off-guard. Any better ways to 'crosscut' stuff on a router table?

johnnyb · 24 Jan 2023

try a bit of sandpaper on the gauge and clamping as well.

Kicked Back · 24 Jan 2023

So it seems this is the reason coping sleds are a thing. Guess I have to make a jig to start making my jigs. Jigcepton.

Bojam · 24 Jan 2023

Kicked Back said:
So it seems this is the reason coping sleds are a thing. Guess I have to make a jig to start making my jigs. Jigcepton.

Yeah, think a coping sled is the best approach here. I’ve had similar problems with narrow stock (where there isn’t enough reference surface against the fence).

I have the plans and bought the hardware (clamps, etc). to make a nice coping sled but haven’t got round to it yet.

Bojam · 25 Jan 2023

These are the plans for the sled I will be making, in case you’re looking for inspiration.

Maybe a bit more elaborate than necessary but has the advantage of not relying on a mitre track. The polycarbonate guide is designed to ride against the fence and is long enough (15”) to ensure that the cuts remain straight/square. The 3 lever clamps keep the stock locked solid during the cut. The handle at the back keeps your hands well away from the cutter.

Spectric · 25 Jan 2023

You could just use the Microjig system of dovetail slots, I put my ones in using a1/4 Makita trim router having first put in a small slot. I put the first one in and then use it to hold a fence to put the next one in and so on, no issues with slipping.