What is this?

[rogdigity]

I just purchased a reloading/parts lot. I can ID everything but this. It belonged to a gunsmith who passed away years ago. Anyone have an idea?

[BDJ]

That is a sine bar. It's used with a mill. You can use it to set up parts at a specific angle. Just google Sine bar and you will see...

[QuarterBoreGunner]

That's cool.
Today I learned what a 'sine bar' is.

[kcstott]

Yep Sine bar.

figure out what the distance between centers of the pins is usually 5" or 10"

say you want to machine an angle at 32.5 degrees

break out your Ti 35 calculator, punch in 32.5, hit sin (sine) X 5 or 10 again specific length between centers of your sine bar pins.
and that equals the stack up you will need to set under one end to get your specific angle.

so it would go like this for a 5" bar

32.5 sin = .537299 X 5 = 2.6864" stack up Joe (gauge) blocks under one end that all add up to 2.686" and your sine bare is now sitting at 32.5 degrees.

[rogdigity]

Cool. Thank you for the input.

It seems like the ones I see when I flagoogled it all have a notch on the lower end of the top face (presumably to hold the work), this one does not though. Any reason why it wouldn't? Or are they all just a little different

[kcstott]

Cool. Thank you for the input.

It seems like the ones I see when I flagoogled it all have a notch on the lower end of the top face (presumably to hold the work), this one does not though. Any reason why it wouldn't? Or are they all just a little different

Some have plates mounted to the ends or machined and ground in steps. some are just flat bars. they all function the same as far as laying out angles go.

[JRJCP]

OP, who was a gunsmith?


Sent from my iPhone using Tapatalk

[rogdigity]

The sellers first husband. Died 6+ years ago

[GoodMachinist]

The sellers first husband. Died 6+ years ago

That mean you don't know or you just being a smarta**?

[rogdigity]

No it means he was the gunsmith. First husband died at least 6 years ago. He was a Smith. Second husband has dementia. He was a bench rest shooter. She's selling all of his stuff because they moved. She told me today they sold over 150 guns in one big lot to a local store. I'm gonna have to go check that place out this weekend!