Bridge City Toolworks - AM-1 Angle Master

[Michael Boyet]

Hello,

I recently purchased a lot of vintage BCT tools. An AM-1 came in the lot. I literally have no idea how to use this tool and cannot find any videos on how these older ones work. Does anyone have an experience with them and can point me in the right direction?

thank you

[Dwayne Watt]

Have you contacted their customer service folks? Perhaps they can get you an electronic copy of the use manual.

[Kevin Jenness]

I believe you use a digital caliper to measure the distance between the pins on the legs and that translates to an angular value. It came with a printed table (reference guide). The Bridge City site doesn't offer any support for that model, but perhaps a call would help. Maybe you can find another owner who would make a photocopy.

[Steve Demuth]

The tool itself is just an angle setting gauge based on the principle of a machinist's sine plate, but that requires a manual to operate. You set the angle between the two legs by looking the angle up in the reference book, which will tell you which holes to put the numbered and lettered brass pins in, and a measurement in inches (or mm if you prefer). You use a ruler and large caliper or trammel set to set the distance between the two pins to that measurement (the points of the calipers fit into the depressions on the pins). Voila, you've set the angle gauge. It handily fits in a 3/4" miter slot, so you can use it as a reference to set your saw miter gauge, e.g.

Edited to Add: The tables also gave the distance across the two pins on the short arms of the tool for each angle, and you if you had machinist's caliper, you could use that across those to do the same setting operation. It's almost exactly a sine plate, in that mode.

The conceit behind the tool is that the pin locations were chosen and precisely drilled so that every angle you might need to set requires a measurement between the pins that is an integer number of sixteenths of an inch, or mm. So you get any angle you want without having to read a ruler to any precision greater than 1/16". But it's pretty worthless without the table of pin locations and measurements. Too clever by half, in my opinion.

Bridge City also published a booklet that described how to make compound miter cuts using the tool to set the angles on your saw. But there are multiple good youtube videos on how to do that.

[Michael Boyet]

thanks everyone. I do have the manual just was not sure how to actual use it to set a tool up. The guide does not indicate this.

[Dwayne Watt]

Maybe your best option is to put it up for sale on that infamous e-auction site. I see listings in the $200 neighborhood, but of course that does not necessarily equate to sales. I found this listing that talks about this tool circa 1997. https://bridgecitytools.ca/pages/1996-2000