Homemade torque screwdriver

[peter nap]

I need a few ideas please.

I need to torque the forearm screw on my Handi Rifles, the same amount each time.

I know, I can buy a torque screwdriver...but I want to try a homemade one.

The best Idea I've had so far is using a flat spring inserted in a drilled hole in a screwdriver and used as a T handle (Holding it by the tips of the spring)

Any other ideas?

[dominicfortune00]

Some scope a few years back came with a shaped allen wrench that you could only grip with two or three fingers to control the amount of torque applied for consistant tightening.

Something like that might work for you.

[peter nap]

Some scope a few years back came with a shaped allen wrench that you could only grip with two or three fingers to control the amount of torque applied for consistant tightening.

Something like that might work for you.

Like the tension wrench for lock picking???????????

[Cap'n Morgan]

Instead of a spring use a solid rod with the screw driver, and use a pull scale for tightening.

[lmcollins]

I would use a weight rather than a spring scale: it is more uniform. If I remember my hi school physics 1 pound applied one foot from the fulcrum equals one inch pound. Therefore: 1 pound applied six inches from the fulcrum would equal 6 inch pounds.

I think I've got that correct: think through my logic.

I use a regular inch pound tourge wrench with a 1/4 inch socket on it, and put the appropriate Brownell's screwdriver bit in it for whatever fastener I'm using. If you want to use a piece of tape around the socket/ bit joint to hold it.

[Owens]

Actually, 1 pound at a 1 foot radius is 1 Ft. Lb. or 12 in. Lbs.

[peter nap]

Actually, 1 pound at a 1 foot radius is 1 Ft. Lb. or 12 in. Lbs.

I think you're right Owen but I like the weight idea. I need about 25 inch pounds, so correct me if I'm wrong. A 2 pound weight at 12.5 inches would work??????????

[grages]

Owens is correct.

grages

[Owens]

peter nap,


Its simply (force x radius)
If the radius is in inches and the force in pounds, the result is in inch pounds.
It could be inches x ounces producing inch ounces of torque (yes, it exists)
Newton-meters
etc...

Your 25" lbs would be:

25/12 = 2.08 feet

So, 1 pound at 2.08 ft

or

2 pounds at 1.04 ft



hope that helps
regards, Owens

[peter nap]

peter nap,


Its simply (force x radius)
If the radius is in inches and the force in pounds, the result is in inch pounds.
It could be inches x ounces producing inch ounces of torque (yes, it exists)
Newton-meters
etc...

Your 25" lbs would be:

25/12 = 2.08 feet

So, 1 pound at 2.08 ft

or

2 pounds at 1.04 ft



hope that helps
regards, Owens

Yep, helped clear out the cobwebs (mentally).

I'm adding a rod to a driver holder and threading the last 6" of it. I'll just cast a 2 pound weight around a nut and thread it on. I can adjust it in or out to compensate for the nut or give different torque.

Thanks!

[TAWILDCATT]

I used to make screw drivers.we used flat spring stock.I have one of the tools now.my frend did not have the finances to keep going. but he mad torque wrenches for the mines in the south in the hundred ft pounds.he was designing digital and I made the heads out of block aluminum. I have philips and flat bits and plastic handles.he was maniger of a plant in North Attellburg, Mass.they went out of business after he left.

[ETG]

Faster and probably not much more cash - 1/4 torque wrench from Harbor Freight and use the appropriate bit. This is what I use to mount scopes.