Fritz and Franz runner reference

[Carl Beckett]

Agree about wanting to drop it in and out from the top

I do have the back piece of the jig with a runner that extends about 6” to give a longer reference

And most of the time the front piece is against the main fence

So it can have some slop and still function well, but not if you want to measure off the jig or set stops precisely.

But it has worn quickly to where slop with the runner. And looking at it more closely this time I see why, the sharp edge. Aluminum. Which will wear over time if I abuse it and have a slot that isn’t uniform over the length

Doesn’t sound like other MM owners have experienced a problem. As a straight material replacement I like the Delrin approach. I have one other idea I want to try first

[Brian Holcombe]

Bearing bronze will work also.

Another option would be to install fitted bars into the slots that are bored for pins.

[Jim Becker]

I agree, but at least the wider slot walls shouldn't wear the runners as much.

I guess that someone who is constantly using the fixture could theoretically wear the aluminum slot edges with a hardwood runner, but the risk is still pretty small. Using HPDE as someone else has mentioned could mitigate that. I think the flexibility of "drop on" is worth any small risk of wear, but others might feel differently.

[Erik Loza]

I’m actually kind of surpised HDPE works for this application. Would have thought that you’d pull the threads out but maybe because I’m mostly used to eccentric clamps and not smaller jigs?

Erik

[Carl Beckett]

Another option would be to install fitted bars into the slots that are bored for pins.

I am going to try something like this.

Even if the hardwood doesnt wear the aluminum, the hardwood itself wears too quickly. UHMW and HDPE are just too soft imo (I like it for many things but not this one). If I can not come up with a clever drop in design, will just replace with delrin and see how long it lasts this time.

This slot seems like it was just never intended as a miter slot.

[Wes Grass]

It's not a miter slot. It's a t slot for clamping the the giant miter gauge (fence) the machine came with.

I'd try delrin and see how it holds up.

I made t nuts for my Felder. The main one is about 11" long and has a precision bore to locate the fence pivot. I'm going to eventually install 2 more spaced evenly so fixtures can drop on and be dead square. Need to make a fixture to get them lined up with each other.

The Felder slot is extruded. The top face is machined flat, and the undersides of the t slot are not the same height on each side. Probably some twist in it too. It took some shimming to get my insert level side to side.

Here's a pic' of a data set collected some years back. Brian Lamb put this together from dim's people submitted.T-SlotGeometry.jpg

[Carl Beckett]

It's not a miter slot. It's a t slot for clamping the the giant miter gauge (fence) the machine came with.

I'd try delrin and see how it holds up.

I made t nuts for my Felder. The main one is about 11" long and has a precision bore to locate the fence pivot. I'm going to eventually install 2 more spaced evenly so fixtures can drop on and be dead square. Need to make a fixture to get them lined up with each other.

The Felder slot is extruded. The top face is machined flat, and the undersides of the t slot are not the same height on each side. Probably some twist in it too. It took some shimming to get my insert level side to side.

Here's a pic' of a data set collected some years back. Brian Lamb put this together from dim's people submitted.T-SlotGeometry.jpg

Yes. Except on the minimax that dimension 'B' is about 0.050" at most. This is the location feature if used as a miter slot.

[Carl Beckett]

I went ahead an made some 'T' bars that locate on the sides at the bottom of the channel. The 'D' surface in Wes image. I just leave it in the slot and lift the F&F off it (put a small bump in it to lock together when sliding. It did tighten things up, and there is not contact on the knife edge region now. We will see how it works over time. While I was at it I made some adjustable plates to accommodate different blades. Am going to see how this behaves over time.
IMG_4406.jpgIMG_4404.jpgIMG_4405.jpgIMG_4408.jpg

(shop setup, after moving, is coming along and it has been satisfying to take care of some things.)

[Dan Friedrichs]

That's clever! I like it!