Making screws

[DMBParticipant @dmb]

Hi All,

Currently working on a project requiring a couple of small screws which I don't have, so make 'em! It's a Myford accessory so thinking about what I need looks similar to the screws holding the wiper on the side of the cross slide. Don't currently have a ready means of making nice Roundheads so settled for slotted cheese heads, quicker and easier. I chucked a piece of 5/16" steel bar and turned down a half inch length to .186" dia and put starting taper on the end and ran the 2BA die up as far as it would go. I then reversed the die and ran it up again, so as to get thread as close as possible to the head. Parted off with a generous height of head, ready to finish both screw to identical head height. Next, I drilled and tapped 2BA, the same steel bar to make a holder. Time of writing this, it's as far as I got last night. Next step, simple jig making, put screw in end of threaded bar and turn heads down to identical heights. Then mount horizontally in mill vice and set up a thin circular saw central to the screw head diameter and slot both screws in turn. They are to hold the stop plate on the LH side of a GHT rear toolpost, where the plate will protrude below the base against the LH side of the cross slide, providing quick simple alignment.

[DMBParticipant @dmb]

[Martin KyteParticipant @martinkyte99762]

Thats a lot of faff for a screwdriver slot, I have 3 knife files invarious sizes and just file mine. They look very good and are tapered to suit the blade of the screwdriver so the heads don't get chewed so easily in use.

Example of files here

**LINK**

regards Martin

[JasonBModerator @jasonb]

Depends how you grind your screwdriver, those ground with two concave faces tend to have little or no taper.

It's a slitting saw for me with the screw in the 5C indexer, soon knocks out a batch with identical slots

[Nick WheelerParticipant @nickwheeler]

Slotting two small screws that won't get used very often?

I'd use a hacksaw.

A couple of dozen of them? Time to set up a collet block and slitting saw. Or the toolpost spindle and a Dremel cutting disc.

[bernard towersParticipant @bernardtowers37738]

Im with Jason if you are going to to the bother of making them do it properly.

[Nick Clarke 3Participant @nickclarke3]

Posted by JasonB on 26/08/2022 10:22:11:

Depends how you grind your screwdriver, those ground with two concave faces tend to have little or no taper.

It's a slitting saw for me with the screw in the 5C indexer, soon knocks out a batch with identical slots

I believe a countersunk screw with a domed top is an instrument head – but what are your cheeseheads with a domed top called Jason?

[JasonBModerator @jasonb]

Fillister Head, quite common on older model IC engines

[DMBParticipant @dmb]

I agree with Jason and Bernard on method – looks better. Tried in the past with junior hacksaw, rough appearance and never on centre. It's only a hobby but I'm trying to up my skills and turn out better work. When I need lots of screws, I'll use a quicker way.   Haven't got a 5C device anyway.

John

Edited By DMB on 26/08/2022 16:38:49

[Chris Evans 6Participant @chrisevans6]

5C block and slitting saw for me, I make a fair few for the motorcycle restoration boys.

[bernard towersParticipant @bernardtowers37738]

Yes Chris and those boys like their fasteners to be right.

[Martin KyteParticipant @martinkyte99762]

 

Posted by bernard towers on 26/08/2022 13:13:52:

Im with Jason if you are going to to the bother of making them do it properly.

These two were done with a knife file. It's a watch and clockmakers technique so it is doing it properly (unlike the junior hacksaw method). I suggest it for the odd screw or two because it's quick, you can adjust the centering as the cut deepens (I start mine against a thumbnail). If I were doing a lot then yes I would set up with the slitting saw but it's nice to have alternative methods to hand which is why I pointed it out. The heads were domed with the hand turning rest which gives an idea of the centre by the way the light falls. These were for my retractable topslide which was never intended to be exhibited so they only have to satisfy me in my workshop. In fact the top one has been in and out a few time and probably not with the best fitting screwdriver either, the lower one is more like the condition it was made in. As for class I believe George Daniels would use a file but then he was much better at it than me.

regards Martin

Edited By Martin Kyte on 26/08/2022 20:48:28

[Chris Evans 6Participant @chrisevans6]

Posted by bernard towers on 26/08/2022 17:40:59:

Yes Chris and those boys like their fasteners to be right.

They certainly do, I now know the difference between a Bracebridge Street Norton 1/4" nut and an AMC Plumsted 1/4" nut. The Bracebridge street nut only has a single chamfer.

[Jon LawesParticipant @jonlawes51698]

I slit all my slot headed screws with a hacksaw; I'm not in a hurry as it's not commercial work, just for my pleasure, and the end results tend to be pretty good even with me at the helm.

[roy entwistleParticipant @royentwistle24699]

At one time you could buy slitting files for making screws for clocks and watches

[Kiwi BlokeParticipant @kiwibloke62605]

Whether a screw slot should have tapered or parallel sides depends on what sort of screwdriver will be used on them – or vice-versa. Unfortunately, Murphy's law says that, however well matched, the screw will still get disfigured. The very narrow slots found on older firearms are quite a good idea: the gunsmith's turnscrew wedges quite tightly in the slot. The last thing you want is for the driver to jump out of the slot, and skid across expensive engraving…

I think that, if I were in the OP's shoes, I'd have used a button head socket cap screw. To hell with the expense!

[BazyleParticipant @bazyle]

One of the awkward things is to make sure the workpiece doesn't turn in the holder when using a threaded one rather than a collet if said holder is not slit and pinched in the vice. In case anyone haven't thought of it one technique is to thread through a short holder and insert a screw from the rear to jam against and lock the workpiece.

[Martin KyteParticipant @martinkyte99762]

Posted by roy entwistle on 26/08/2022 22:05:32:

At one time you could buy slitting files for making screws for clocks and watches

You still can, as I have been advocating for small numbers.

regards Martin

[DellParticipant @dell]

I know this is an old thread ( pun intended) but I restore torsion clocks ( glass dome ) a lot of the clocks I get across the bench have butchered screws, I try to dress them re polish and blue because I prefer to keep original if possible but sometimes I have to make new ones, 12BA and larger, 1.2mm and larger I have slot files but because my hand aren’t very good I struggle to use them successfully, I have a pin vice in a tool holder that I put on the crosslide as well as another device for larger screws and a 0.3mm slitting ( slotting) saw in headstock and it gives a very neat slot.

[VicParticipant @vic]

Posted by bernard towers on 26/08/2022 13:13:52:

Im with Jason if you are going to to the bother of making them do it properly.

Yes agreed. How much bother is it to spin a slitting saw in the mill anyway?!

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