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Brett Hurt
04-05-2011, 12:12 AM
I made a screw and know how do I slot it. So the slot is in the senter of the screw, I did one and it was off a lot. I alined the screw with my slitting saw marked the line on the screw senterd it all up on my mill and opps it was off. Or how should I hold it, I used my indexing head with a 3 jaw chuck Brett

Michael Moore
04-05-2011, 12:51 AM
Brett, I'd bring the saw down to just touching the top of the screw. Then move the saw down 1/2 the OD of the screw + 1/2 the thickness of the saw. That should get you within a thou or two of being on center.

cheers,
Michael

gary hart
04-05-2011, 01:16 AM
Brett, as Michael says. You say your using a indexing head, then after making the cut rotate the work 180 degrees and make another cut. This should guarantee the slot will be in center of screw. gary

Black_Moons
04-05-2011, 06:55 AM
Brett, I'd bring the saw down to just touching the top of the screw. Then move the saw down 1/2 the OD of the screw + 1/2 the thickness of the saw. That should get you within a thou or two of being on center.

cheers,
Michael

Pertty much, However I would recommend getting some zigzags (Cig rolling papers)
You put the paper beween the work and tool, And slowly pull it out from beween them while slowly cranking the axis on your mill

Eventualy, the paper will get grabed beween the tool and work and likey rip. This tells you EXACTLY when they contact.. well, +0.001" or so. (Zigzags are a rather reliable thickness), And will tell you when they contact much more accurately then by eye or feel on the axis knob. Plus more likey to make you stop cranking the axis before they hit so hard as to damage the tool. (VERY easy to do with anything carbide (Brittle!), Little harder with HSS)

Once you know where the tool touchs, Do it once more extra slow and careful to confirm the exact position. (This will go really fast since you only have about 0.005" of cranking to do since you know almost exactly where it should contact)

dalesvp
04-05-2011, 08:58 AM
To hold the screw for slotting bore and tap a thick piece of metal (thickness = screw thread length) mounted in the mill vice. Insert screw, if needed add a set screw at 90 degrees to hold the screw tight. I have slotted the heads of many threaded pins this way.

The Fixer
04-05-2011, 09:28 AM
U know u can buy screws already slotted.......

38_Cal
04-05-2011, 09:31 AM
If you are doing a bunch of screws, use the index head on the mill. If you only have one or two to do, you can save a lot of time with setting up by using the screw slotting fixture that I designed when I worked for Brownells: http://www.brownells.com/.aspx/pid=18694/Product/SCREW_SLOT_FIXTURE

Too bad I don't get royalties!

David

Highpower
04-05-2011, 09:48 AM
I have one of those nifty little tools! :)

Use it all the time to straighten out buggered screw slots caused by Bubba and his tapered Sears screwdrivers. ;)

Kudo's David.

Brett Hurt
04-05-2011, 10:21 AM
I will try it and let you know oh with the rolling papers can I use them any otherrrr way Like I used too do in 60"s Brett

philbur
04-05-2011, 01:20 PM
Don't forget that the quill feed on your average mill/drill isn't always that precise. Check it with a dial indicator.

I had one that was graduated for 2.5mm per rev and was actually 3.0mm per rev. Even afer fitting a new dial a bit a rack/pinion binding made precise Z axis positioning a bit hit and miss. An HSMer could run a mill for years and not notice, until a part requiring a precise depth, like a screw slot.

Phil:)

im#2
04-05-2011, 01:42 PM
No brett go easy on them that way we dont want to cause a shortage like there was in the 60's.

Mike Hunter
04-05-2011, 02:16 PM
I make a few screws here in the shop. For a while there I was having issues with buggering the threads when slotting.

What Iíve done was to drill & tap a 5C emergency collet to the screw size, then hold in a 5C Collet block, and mount in my vise.

I donít like using a slitting saw, way too much runout. I ground a keyway cutter to the correct width, then, center on screw head & cut.

Brett Hurt
04-06-2011, 12:03 AM
I used the zigzags and it worked I made 14 of them out of SS 12/24 thread 1in long .040 slot look great thanks for the info Brett

Ed P
04-06-2011, 09:14 AM
If you are doing a bunch of screws, use the index head on the mill. If you only have one or two to do, you can save a lot of time with setting up by using the screw slotting fixture that I designed when I worked for Brownells: http://www.brownells.com/.aspx/pid=18694/Product/SCREW_SLOT_FIXTURE

Too bad I don't get royalties!

David

I'm having a hard time seeing it on my monitor. It appears as if the capscrew on the side is used for clamping the screw to be slotted and that said screw is held by its threads, one side against the capscrew, the other against the hole of some kind in the jig. Is this correct, and if so do the threads not get damaged in the clamping process?

Ed P

Richard Wilson
04-06-2011, 01:08 PM
I made a screw and know how do I slot it. So the slot is in the senter of the screw, I did one and it was off a lot. I alined the screw with my slitting saw marked the line on the screw senterd it all up on my mill and opps it was off. Or how should I hold it, I used my indexing head with a 3 jaw chuck Brett

Done that myself. Hold the screw in the indexer, cut the slot as close as you can, then spin through 180 degrees and cut the slot again. It might end up a bit wider than you intended but it will be central.

Richard

Highpower
04-06-2011, 04:10 PM
I'm having a hard time seeing it on my monitor. It appears as if the capscrew on the side is used for clamping the screw to be slotted and that said screw is held by its threads, one side against the capscrew, the other against the hole of some kind in the jig. Is this correct, and if so do the threads not get damaged in the clamping process?

Ed PThe "hole" in the jig is a V-block that centers the screw between the rollers. You don't have to crank down on the cap screw to hold your work piece in the jig. Just enough to hold it in the bottom of the V. You could slip a brass or lead strip between the screws if you wanted, or simply replace the cap screw with one that has a brass or nylon dog point on the end it it. I haven't found a need to do that though myself. I just touch the threads and stop. Never had a problem.

38_Cal
04-06-2011, 05:30 PM
The "hole" in the jig is a V-block that centers the screw between the rollers. You don't have to crank down on the cap screw to hold your work piece in the jig. Just enough to hold it in the bottom of the V. You could slip a brass or lead strip between the screws if you wanted, or simply replace the cap screw with one that has a brass or nylon dog point on the end it it. I haven't found a need to do that though myself. I just touch the threads and stop. Never had a problem.
What Highpower said. The only time you might have a problem is with a tapered screw, like the tang screw on a Winchester HiWall, and get the slot slanted. On my prototype, the end of the clamp screw was polished smooth. Unfortunately, the prototype "disappeared" in the purchasing department...:mad:

David

Silverback
04-06-2011, 08:02 PM
WRT holding the screw, cut a slot in one side of a matching nut, thread the screw into it and clamp it in a vice, it will protect the threads and when you clamp it it won't turn...

dp
04-10-2011, 11:01 PM
Here's a how-to I blogged when I made some oval head brass screws.

http://metalworkingathome.com/?p=40

Hal
04-13-2011, 10:12 AM
Brett

If you don't have rolling papers you can use an old phone book.
A hint from Frank Ford's web site of helpful hints. He just runs an old phone book through the band saw and cut the book into several pads, one for each machine.

Hal