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I am debating whether the gantry should be horizontal with a brake in the same plane as the wheels or vertical screwing in through the gantry plate. I will make a picture.

 

So I am thinking either of these. These are just quickly thrown together, those handles are not to scale they are just models I found. There are three bolts to attach the rail to the table so I cannot do the vertical rail

 

Its design phase. I am not building yet.

 

For cost sake, I think it is best to stick with a brake like this.

 

Let me know how that bicycle hub goes because that seems to be cheap strong and other than a bit long, perfect

 

What does the top of the bolt look like before modification? Does it thread into a nut inside that cam lever? I think I would prefer to cut on that end and save buy an m8 bolt, mostly because I would want to buy an m8 bolt with a t-slot end.

Maybe I will stop being cheap and get some of these McMaster-Carr

 

Now another engineering debate. Because these are soft wheels, I have to be careful about how the clamping force interacts with the wheels on the rail. Do I use one on each side of the fence and/or on both gantries?

Depending on what I do it could tilt the fence or pull the bearings out of the wheels.

I almost wonder if I could put the clamp on another wheel and use that as the brake in line with the rest of the wheels.

 

The brake just showed up, but now I am having second thoughts. Its almost a waste to invest so much good material (open builds) in my terrible table saw.

 

So I finally did some work on this. I stumbled across a small toggle clamp which worked perfect if not over priced. I did a POC using nuts as spacers so I could double check my measurements and calculations. I just ordered my 40mm spacers and my 60mm shoulder bolts. I ended up not likely the hub clamps mentioned above because they snapped too easily. I would have rathered use the toggle clamp in a direction either opposing the wheel axis or braking on the rail but the fasteners prevented that.

 

I need some help. The delrin wheels allow the rail to flex when clamped down. This is exactly why I didn't want to clamp with force perpendicular to the radial axis of the wheels. Would the polycarbonate or steel be better

 

I could do a corner bracket or a cube but I would probably need spacers to get the position perfect. This little clamp is strong for its size and the price was killer cheap compared to what I expected. I wanted to position it under the plate but then the open position has no room for the handle.

They are discontinued and although I can find similar, I think the required close tolerances would be a deal killer. It would have to be basically rubbing on the top.

That was the original plan but I was having trouble finding the right hardware to enable it. The bicycle clamp was very very cheap, but it was very very very very cheaply made. Snapped one of them and then the other I still have yet to find (whoops). Nice Idea about the notches but I prefer to have a scale on the table, tape like that is fairly cheap.

I tried that, the screws and nuts on the underside of the plate would rub the rail. Its not even close where I could just grind down the nut and cut the screw. It is tight. Might try polycarbonate if this all fails. Thanks.

 

So, I found this little angle bracket in my junk bin and it worked. Also, my shoulder bolts and spacers came in and everything is perfect.

 

Well back to the drawing board. If I want to use the miter slot, then I need to move the spacer and bolt attaching the table to the top slot of the extrusion . If I do that then I can only used rollers on one side of the carriage. So I think I am going to order some openrail to stack on top of a 20x20 extrusion instead of the 20x60. Of course that will flex more. And I will also have to redo the spacers under my rollers to adjust the spacing of the main fence and table height.

 

Done. The spacers weren't perfect, but after spending $25 bucks on spacers which I thought were perfect and they weren't I was willing to do some finangling.

I need to find some square spacers or I will try to just use small bits of extrusion. I also need to find a small L bracket that is better for the brake but for now it works perfect. The fence is a bit long so I will need to cut that too. All and all I am happy