Screw slot files?

[J Shingler]

Does anyone make screw slot files any longer?  They show up in the OLD catalogs of file manufactures but seems to be a lost product to CNC and slot cutters now.

Jeff

[Pete G.]

I got mine at Brownell’s

[Bob Roller]

All or nearly all of my lock screws were slotted with a miniature hacksaw with no "set" in the teeth which are 32 per inch.
The a few strokes then with a small knife shaped file.Job done.I suppose Frank Mittermeier in NYC is long gone by now.
Bob Roller

[kutter]

You can still buy them from watch repair, jewelry and other such supply houses. The files are generally Euro made, or at least branded as such.
Expensive buggers at around $40 to $60 a piece.

I have exactly one that I bought maybe 50yrs ago and still hardly ever use it.

I slot the screws, or re-slot damaged ones with a Jewelers saw using wide blades.

Most places sell blades up to a #8 width which is .020" wide.
But they are made up to size #14 width (at least) wjich is .024

I use the #8 size . If I want the slot a little wider 'looking'..I taper the top edge of the slot with a very narrow safe edge (back side) needle file. Taper both sides of the slot just a touch and the slot will look remarkably wider.
Since the opening is only wider at the very top of the slot, the screw driver needed will still be a very narrow one to fit down into the orig cut.
The advantage is that there is very little chance of 'twisting the slot' becasue of the clearance given by the taper filed to the top edge.

Sometimes I use the saw to place a second cut next to the first for a full depth wider cut. With sharp saw blades, it's very easy to plunge a second cut next to the first, or even a partial wide second cut.
The blade leaves a nice squared edge bottom to the cut as well.

A very fine tooth hacksaw blade can be used as well with the 'set' taken out of it by carefully grinding the sides on the belt grinder,,or by hand with a stone. That leaves a nice width screw slot saw.
The blade won't cut deep w/o binding once the set is gone, but screw slots are rarely that.

[flatsguide]

Look up “Gesswein”. They sell them. A tip on filing the slot is first chuck up your screw or bolt in a drill motor, drill press or lathe and take some 220 or 320 paper and polish the screw or bolt head. The resulting circular finish on the head will show where the center of the part is. Then with the screw or bolt held firm place the file on the edge of the part and slowly push the file towards the center, the mark left by the file will let you know if you are right or left of center start filing and correcting as you go.
Cheers Richard

[Jerry]

All or nearly all of my lock screws were slotted with a miniature hacksaw with no "set" in the teeth which are 32 per inch.
The a few strokes then with a small knife shaped file.Job done.I suppose Frank Mittermeier in NYC is long gone by now.
Bob Roller

Bob, Frank Mittermier in NY was my go to place for German chisels back then. Still have them. Don’t use them much anymore, but enjoy them. Jerry

[Bob Roller]

Jerry,
Sounds like you also have been around for a while.Frank Mittermeier and Robert Abels were 2 New Yorkers that we could trust.
Abels teneded to under rate his guns.What he said was "good"was one I would call "fine".Good tools are seldom cheap and for
these tiny files and saws when needed are well worth the money. IMHO.I have a set of British "needle" files that I bought about
60 years ago and still use them and all of them are there,none broke.
Bob Roller

[Dan Fruth]

I use files designed for making string slots on guitar nuts. Much cheaper and work great. Here is a link 
https://www.stewmac.com/luthier-tools-and-supplies/types-of-tools/files/double-edge-nut-files/

[P.W.Berkuta]

I use files designed for making string slots on guitar nuts. Much cheaper and work great. Here is a link 
https://www.stewmac.com/luthier-tools-and-supplies/types-of-tools/files/double-edge-nut-files/

How do these files stand up to cutting steel? Do the wear quickly or hold up for cutting many screw slots?

[P.W.Berkuta]

Depending on what type of slot I want I use a hacksaw and a knife edge file or I use a milling machine with a slitting saw blade. I can make screw head slots from 0.015" to 0.062" with a single slitting saw blade or I can gang multilabel blades to get the desired slot width that I want. Most of the screw slotting files I have seen are VERY costly.

[Clark Badgett]

Are we talking parallel side screws or taper side screws?

[J Shingler]

Thank you for the great tips and replies.  Yes I have been using a hacksaw with the set ground off.  My understanding was the original screws slots were not parallel sided. More of a V shap notch. At least the side lock bolts.
Thoughts?

[Jim Kibler]

Yes, it’s hard to beat a knife shaped file.  Ordinary tapered screwdriver bits snug in place and the slots look right as well.

[Dphariss]

All or nearly all of my lock screws were slotted with a miniature hacksaw with no "set" in the teeth which are 32 per inch.
The a few strokes then with a small knife shaped file.Job done.I suppose Frank Mittermeier in NYC is long gone by now.
Bob Roller

I grind the set off the saw and it works great. Files are a lot slower and to me harder to use. Yes a knife needle file is useful as well.

[Dphariss]

Yes the taper is what the knife file is for. Straight cut slots tend to burr more easily than those with a slight taper. I also case harden and then heat blue screw heads. Saves a lot of grief and replaced screws.