How are screws indexed so that one (or more) slots points in the same direction?

You use a countersink and take out very little at a time. I call it the try fit method.

Others may have a more precise way of doing this but in essance you take a little metal out of the screw hole to allows the scre head to sit deeper in order to align the slot.

this question came up just the other day. The way I do it when using an existing screw is to turn a little bit off the bottom of the screw head until it lines up. I have a very high-tech way of doing this: I chuck the screw in either a drill held in a vise, or a drill press. I then turn on the motor and dress down the bottom of the screw with a knife edge file. Not that way you would build a Siss watch, but it works fine for getting slots running "North and South."

If I am making a screw from scratch, I make the head very long and cut a shallow slot in it. I tighten it up and file off the top of the head. I then mark the direction I want the final slot and start the cut running North and South. I deepen the notch and then file down the screw head to the correct height and profile (dead flat or slightly domed). The easiest way for me to cut the notch is with a slitting saw turned in the mill.

if it is close, i have aa different approach...

on a sanding block with 220, i sand a HAIR off the leading thread, which changes the starting location of the screw.. and since the turns are defined, it will change about the same.

since the most you are going is 180, you would take off, at most, 1/2 a thread

jeffe

quote:

Originally posted by jeffeosso:
if it is close, i have aa different approach...

on a sanding block with 220, i sand a HAIR off the leading thread, which changes the starting location of the screw.. and since the turns are defined, it will change about the same.

since the most you are going is 180, you would take off, at most, 1/2 a thread

jeffe

What??? Doing it your way ain't gonna change a thing, other than shorten the shank a hair. The screw will bottom exactly the same as before. You have to change the point of contact with the bottom side of the screws head in order to change the position of the slot. You either do this by removing from the underside of the screws head, as was previously stated by Marc, or, by deepening the counter bore as was stated by 54JNoll. Draw a picture of the problem and see if you can spot your error.

I have to agree with Malm. He is afterall a bonafied gunsmith and has actually "done" this type of thing in reality.

Jeffe,
Just think about the relationship of the starting thread in the hole and the bottom of the screw cap. None of that has changed. All you did was start the screw in a slightly different orientation but it will still stop in the same place as it did before.

Jeffe:

I just lost a helluva lot in determining your talents.

WowZ!

Jim

Well just because my swiss cheese brain couldn't see the logic it that sand off the bottom of the screw method I had to go test it. Took a screw and nut. Market them when fully seated. Then started sanding off the bottom. 1/4 turn at a time. The screw and nut stayed in their starting positions. Might work if the screw bottomed out.

But hey I've been wrong before and will be again.

Cossak,

Did you forget your original post regarding this question?

https://forums.accuratereloading.com/eve/forums/a/tpc/f/9411043/m/427102325

in a screw that stops, changing the length changes the stop, but that's probably not the question.

i'll post a pic tonight, as a pic saves typing 1000 words

Jeffe, haven't you ever noticed that no matter how many threads you remove on a gun barrel, the sights never seem to change, or, come up straight? The term "setting the barrel back a thread" is only figurative.

Hey malm, I'm sure not expert. But if you have a Mauser that bottoms on the C ring and not the shoulder if you remove thread doesn't the site shift as long as the shoulder doesn't hit? Yep normally you remove thread and shoulder.

Or am I missing something.

quote:

Originally posted by ramrod340:
Hey malm, I'm sure not expert. But if you have a Mauser that bottoms on the C ring and not the shoulder if you remove thread doesn't the site shift as long as the shoulder doesn't hit? Yep normally you remove thread and shoulder.

Or am I missing something.

Yup, if you were working with Mausers and only contacting the "C" ring, then you would make the adjustment by removing that which was touching. Which would be the point of contact as would be the bottom of the screw head.

Jeffe,
Save the picture. It will not work in this situation the threads they are going into are already established. If you grind off 1/3 of a screw,all it does it saves you turning that screw in that 1/3 of a turn. This is really simple stuff.

The relationship to the direction of the slot and the rest of it's world is fairly simple. It is controlled by the female threads the bolt or screw is going into and the distance from the stop to the threads. The threads are constant on the bolt and in the action, the distance has to be changed by either cutting on the bearing surface in the countersink or on the bearing surface on the bottom of the head of the screw. That is your options, pure and simple.

Thanks malm,
Just wanted to make sure my mind wasn't completely gone.

quote:

Originally posted by ramrod340:
Thanks malm,
Just wanted to make sure my mind wasn't completely gone.

Nope, you appear to have enough of a mind left, to figure things out with.

The arguement that changing the "thickness" of a screw head(either machine or wood) is the only way to change the position of the slot presumes that the two parts held together by the screw (metal to metal or metal to wood) are fixed in position.

For most applications this is correct, but for some the spring of the piece will allow indexing to occur by simply overtightening the screw, moving the parts together. I ahve seen this on unsupported tangs on lever guns, and ill fitting bottom metal and other gun parts that should be backed up by wood, but are fitted loosely and don't truly "bottom" as they should.

Assuming the parts are fit (bedded)properly, overtightening to index either compresses the wood, tears out (strips) the threads, stretches the screw, or turns off the screw head. This is true if the screw has full length threads, or if you cut all but one thread off.

Sometimes there is more metal to work with in the part than the screw, and it works fine to countersink a bit deeper. Either way, the head sits just a fraction deeper in the part.

BTW, I see no benefit in funtion, and have always thought it a waste of my time and effort to bother with this. If I had the skill to make some of the pieces shown here, I might feel differently.

Roger

Chuck the screw up in your drill press and file the back of the head. Try and fit. Dont take to much off the back at once or you will have to go all the way around. Nothing to it really.

Prewar 70
No I didn't forget it, just couldn't find it...even when I used the search option. Though I may have forgotten to hit the Post Now button. Did not intend to jerk chains by seemingly posting again.