Looking for screwhead slotting file recommendation

[dadistic]

Now that I finally have my lathe and collets up and running, one of the next steps for me is making screws.  I have everything I need, except for a way of making the slot.  This means I need to invest in a screwhead slotting file, but the darn things are really expensive and I want to make sure I'm getting the right file for the job I want to start with.

I'm going to attempt to make a crown wheel screw. It has a ~1.5mm head, and about a .2mm slot. Relatively large, which is why I'm starting with this.

I *think* I want a Vallorbe LP1840 cut 4,  but I'm not sure. the 1840 has a tang, there is also the 1850 which doesn't.  The 1840 goes to cut 4, and the 1850 goes to cut 8.

I have the Vallorbe catalog, but I still haven't figured out for sure what I need in terms of the cuts, which also determines the thickness of the file. 

Cut 4 is 0.55mm  

Cut 5 is 0.5 mm

Cut 6 is 0.45mm

Cut 8 is 0.35mm

Help?

[nickelsilver]

I don't think anyone makes them except Vallorbe now, and pretty sure the 0.35 is the thinnest still made. That's still a bit wide for most wristwatch screws; 0.20 is pretty normal. But it should still be ok (the 0.35).

 

I have 2-3 dozen I've bought second hand over the years, always searching for and coveting the thinnest ones. They are often chipped here and there but even chipped ones usually have enough undamaged surface to be useful. With or without tang isn't an issue, probably 99% of mine don't have it.

 

Some only cut on the edge and have pretty parallel sides, some are more wedge shaped and cut on the sides as well.

 

When making a screw I will hold the screw to be slotted either in a tiny vice (Horia) with a v-slot in the jaws that holds well without deforming the threads, or sometimes in a bench block if the screw fits closely in a hole, or if feeling fancy in a little collet holding tool (good for very small screws), and do the slotting under microscope. It's very easy then to center the file, take a couple strokes, if it's slightly off correct and then file away.

[dadistic]

Thanks!

I can't find the cut 8 Vallorbe, but I did find cut 8 Grobet. These have a kind of diamond cross section, and will cut a tapered slot.  Smooth on the width, so I could use it on a rest, but I like your idea of freehanding it under my scope.  Practice, practice, practice

I think you've given me enough info to move forward, I'm really glad I asked before buying the cut 4!

Thanks again

(a little bit later)

Heh. Found an interesting suggestion in Fried's Bench Practices for Watch Repairers. 

His idea is to take a single edge razor blade, set the edge on a cut 4 needle file, and then give it a good whack with a hammer. He says this will form teeth in the edge of the razor, good enough to file a screw of "moderate temper".

I check a blade, it's 0.2mm wide. Perfect.  I also have some cut 4 needle files.

I've got to try this!

Edited August 13, 2022 by dadistic

[dadistic]

Well, I have my Grobet cut 8 file, and have made something that almost looks like screw.

Any tips on how to hold such a small file? After fumbling around, I settled on holding it between thumb and forefinger of each hand, and sliding it left to right while keeping some tension on it. The thing is floppy! 

I also had trouble getting the slot started on center, the first strokes were wandering all over the place. 

Ah well, back to making some more test articles to mangle

[Shane]

On 8/13/2022 at 6:21 PM, dadistic said:

take a single edge razor blade, set the edge on a cut 4 needle file, and then give it a good whack with a hammer.

I really hope you wear safety glasses during this.  Razor blades can be very brittle!

1 hour ago, dadistic said:

sliding it left to right

Left handed?

1 hour ago, dadistic said:

I also had trouble getting the slot started on center, the first strokes were wandering all over the place

I have found if you start your cut (guiding off your thumb nail) on the edge (on about a 45° angle) moving to a more parallel attitude as your cut gets deeper and longer.  This gives you the opportunity to adjust for center without scratching across the whole surface while also staying within your kerf.

Also, just for people who may not have a lot of experience with metal working, files really only cut it direction.  One of the fastest ways to dull a file is to apply downward force on the back stroke.  It would be a shame to obtain something so unique and ruin it unintentionally.

Have fun and a good day.

Shane 

 

[dadistic]

Yes, I'm aware that the file cuts in only one direction, but I do have a bit of a problem controlling down force on something so small. I hope I get it figured out before I trash the file

Should have said right to left as that would be the cutting direction, but what I was trying to say is that I was moving the file parallel to my body rather than perpendicular as one would with larger files. 

I'll try your idea of using my thumbnail as a guide, thanks!

[Shane]

13 hours ago, dadistic said:

Yes, I'm aware that the file cuts in only one direction,

I was not necessarily speaking to you, just a tip for those who may need it.  I have seen some things that would make my shop teachers roll in their graves.

As to your filing, I find that I have more control making straight lines pushing away from myself (at a slight angle so I can still see the tool, as well as the work).  Moving perpendicular to your body may give you a tendency to pivot around your own center, causing you to make curved lines and cause difficulty controlling the downward pressure.

Let us know how you make out.

Shane 

[dadistic]

The file is too flimsy to push, it bends. Tension helps, and I'm just moving my fingers,  hands are still and braced on the workbench.

Cheers!

Edited August 23, 2022 by dadistic

[LittleWatchShop]

On 8/13/2022 at 5:21 PM, dadistic said:

Thanks!

I can't find the cut 8 Vallorbe, but I did find cut 8 Grobet. These have a kind of diamond cross section, and will cut a tapered slot.  Smooth on the width, so I could use it on a rest, but I like your idea of freehanding it under my scope.  Practice, practice, practice

I think you've given me enough info to move forward, I'm really glad I asked before buying the cut 4!

Thanks again

(a little bit later)

Heh. Found an interesting suggestion in Fried's Bench Practices for Watch Repairers. 

His idea is to take a single edge razor blade, set the edge on a cut 4 needle file, and then give it a good whack with a hammer. He says this will form teeth in the edge of the razor, good enough to file a screw of "moderate temper".

I check a blade, it's 0.2mm wide. Perfect.  I also have some cut 4 needle files.

I've got to try this!

I am a little late to the party, but saw this and thought I would comment.  I am no expert, but I never give up.  Here is a screw I made a couple of days ago.  I used a Valorbe 8 to cut the slot.  As you say, it is really hard to cross center.  On this screw, I first tried to score a track with one swipe...I cant remember, but I did the return and not the forward cut to do this.  I did it several times until I had a track to ride in.  If I did it again today, I would probably screw it up (pardon the pun).  At the end of the day, I think it is something you learn by feel over time.  I am not there yet but moving in the right direction.

You can see that I did not hit dead center on this screw...maybe the next one, no??

BTW, I bought the file from Esslinger.

Edited September 8, 2022 by LittleWatchShop

[dadistic]

Missed it by thaaat much.  *

Looks good to me, though. I made five little unthreaded test screws that I'm going to use for practice, I'm hoping that I can get it figured out after doing a few. 

Then it's back to trying to make my screw plate work, I've already broken off a screw in the number 7 hole and had to buy some little carbide pc drills to use to get the stub out. Good thing those things are cheap, I broke one right off the bat

After that, it's heat treat time! Not going to try and make the first ones pretty, I'll just be tickled to death if I can get one that is actually functional. 

Cheers!

* Apologies to Don Adams, AKA Maxwell Smart

[Neverenoughwatches]

On 8/23/2022 at 12:24 AM, Shane said:

I really hope you wear safety glasses during this.  Razor blades can be very brittle!

Left handed?

I have found if you start your cut (guiding off your thumb nail) on the edge (on about a 45° angle) moving to a more parallel attitude as your cut gets deeper and longer.  This gives you the opportunity to adjust for center without scratching across the whole surface while also staying within your kerf.

Also, just for people who may not have a lot of experience with metal working, files really only cut it direction.  One of the fastest ways to dull a file is to apply downward force on the back stroke.  It would be a shame to obtain something so unique and ruin it unintentionally.

Have fun and a good day.

Shane 

 

Good advice that applies to any general hand sawing action, start the cut guided and angled up then level off .A look at the teeth will indicate sawing direction but most toothed tools will only cut one way, and that can be forwards or backwards depending on your preference. A thin blade should be drawn backwards with the teeth cut facing toward you or it will buckle. And as shane has said a pressured pull stroke if cutting forwards will soon deaden the tooth's sharp cutting edge. As a fact the Western world saw on the push stroke whereas the likes of Japan etc. Cut on the pull stroke. I have a few Japanese saws that are ridiculously sharp, the pull stroke takes a little getting used to after 40 years of pushing. 

1 hour ago, dadistic said:

Missed it by thaaat much.  *

Looks good to me, though. I made five little unthreaded test screws that I'm going to use for practice, I'm hoping that I can get it figured out after doing a few. 

Then it's back to trying to make my screw plate work, I've already broken off a screw in the number 7 hole and had to buy some little carbide pc drills to use to get the stub out. Good thing those things are cheap, I broke one right off the bat

After that, it's heat treat time! Not going to try and make the first ones pretty, I'll just be tickled to death if I can get one that is actually functional. 

Cheers!

* Apologies to Don Adams, AKA Maxwell Smart

A little trick here. Screws the screws flush into the end of a wooden dowel say 6mm then the dowel into a vice. Then you will have more diameter to work on which will create a guide for the saw file.

Edited September 8, 2022 by Neverenoughwatches

[Neverenoughwatches]

5 hours ago, Neverenoughwatches said:

Good advice that applies to any general hand sawing action, start the cut guided and angled up then level off .A look at the teeth will indicate sawing direction but most toothed tools will only cut one way, and that can be forwards or backwards depending on your preference. A thin blade should be drawn backwards with the teeth cut facing toward you or it will buckle. And as shane has said a pressured pull stroke if cutting forwards will soon deaden the tooth's sharp cutting edge. As a fact the Western world saw on the push stroke whereas the likes of Japan etc. Cut on the pull stroke. I have a few Japanese saws that are ridiculously sharp, the pull stroke takes a little getting used to after 40 years of pushing. 

A little trick here. Screws the screws flush into the end of a wooden dowel say 6mm then the dowel into a vice. Then you will have more diameter to work on which will create a guide for the saw file.

Just noticed a slight unmentioned point lol.  When i said screw the screw into a wooden dowel, this is best done with a pilot hole in the dowel then a pin vice and then tap the screws home. But I'm  sure you would have figured that out. Screwing them out would be possibe