Shopsmith Forums

1. Table Saw
2. Jointer
3. Bandsaw
4. Disk Sander
5. Drill Press
6. Horizontal Boring
7. Panel Clamps (4 way)
8. Scroll Saw
9. Lathe
Used the over head router once. I just

use a router table for most of my routing needs.

AEA wrote: ↑Thu Feb 18, 2021 2:40 pm 7. Panel Clamps (4 way)

Are these the ShopSmith Double Bar Clamps ? Did you make your own bars or use the ones they have?

I use the ShopSmith double bar clamps 2 foot, and 3 foot. I made some from a kit I bought from somewhere, but the ShopSmith clamps are much easier. These are the original already put together. I have no experience with the new option ShopSmith offers.

AEA wrote: ↑Sat Feb 20, 2021 1:14 pm I use the ShopSmith double bar clamps 2 foot, and 3 foot. I made some from a kit I bought from somewhere, but the ShopSmith clamps are much easier. These are the original already put together. I have no experience with the new option ShopSmith offers.

Thanks. I'd like to have some, considering buying Shopsmith parts and making my own bars.

I understand they have a slight radius to the bars so it will tighten down flat, but I'm not sure what they mean when they specify a "3 degree radius cut".

edma194 wrote: ↑Sat Feb 20, 2021 1:30 pm I understand they have a slight radius to the bars so it will tighten down flat, but I'm not sure what they mean when they specify a "3 degree radius cut".

I haven't done this before in woodworking, but I believe you can use calculators like this one (link below) to compute it (sorry I was too lazy to go dust off the math formulae). If you input 3° and specify the chord length as 3', e.g. a 3 foot long clamp, you get a radius of 57.3' for the arc you'll be creating. Of course, this would be a pain to have to draw in the shop with a 57' long board to draw the circle, so you need another option. Once you have the radius and the length of the clamp you should be able to use the 2nd calculator below to compute the height (sagitta) of the arc. If I did these calculations correctly then for a 3' long clamp with a 3°radius you end up with the curved (arc) part being about a quarter of an inch high. So from the center of the caul to the ends the curve would only rise a quarter inch. This quarter inch would sit on top of the rest of the width of the board used for the clamp. Easiest would be to put 2 nails on each side and use something as a bendable form to draw the arc on the board for cutting. Hope this helps, but would be happy to see if anyone has a better/easier way to do it.

https://www.omnicalculator.com/math/arc-length

https://www.mathopenref.com/sagitta.html

I think I'll sand a slight curve into the board and leave it at that. Otherwise I might need a 75 foot string to make this arc for a long bar. (probably not use that long of a bar actually)

I may have this wrong, but I think the idea is to keep the center of the bar down flat on the panel while the ends are tightened. Tension and compression is put on the bar from both ends but the brackets are attached very near the ends and there's no downward pressure directly near the center of the bar.

Not sure what to use for the wood, thinking Birch if I can get a good deal on it at the mill.

There are tape measures that allow for pretty large radius arc/circles. This one can do a radius of 118" but practical would be more like perhaps 72" which is still a pretty large circle.
Ed