Safety files?

[M_Chavez]

Hi All,

Is there a place where one can buy safety files in any shape, size & cut in the UK? E.g. I'm looking for a 2mm and 3mm thick barette file, or same thickness but with teeth only on one small edge (don't know the name for it. Kind of like a barette, but the only cutting face is on the side).

Don't think that I can make my own, as I only have a 6" bench grinder. Something tells me that it won't come out well if I try flattening the teeth on it.

Thank you.

 

[ChaiLatte]

Cookson Gold and HS Walsh have them. They call them 'safety back'.

Cutwel (.co.uk) have **** files.

Vallorbe or Grobet are well known file manufacturers.

What you describe sounds somewhat like the 'joint square edge needle file' sold by ArcEuroTrade, but their one has teeth on both short sides.

https://www.arceurotrade.co.uk/Catalogue/Cutting-Tools/Tome-Feteira-Files/Swiss-Pattern-Needle-Files

 

[M_Chavez]

Bingo! It's called a "Joint" file. Thank you.
Learn something new every day.
The linked one is, unfortunately, only 1mm thick, but I guess I can keep on googling. Between that and a tri-square barrette I can get the sizes & shapes I need.

 

[ChaiLatte]

Bingo! It's called a "Joint" file.

Brownells also call it a 'screw slot file' and that makes sense insofar as it only goes deeper into the slot and does not make it wider.

https://www.brownells.co.uk/SCREW-S...2-FRIEDR-****-GMBH-Screw-Files-5625-249108118
The Arc one is a Portugese manufacturer. They may have a catalogue with other options. The Grobert, Vallorbe and **** catalogues are also probably worth trying to find as pdfs.

Edit:

In the luthier world, you can get 'nut slotting files'. To thin for your original request though.

https://www.gluedtomusic.com/products/184/hosco-gauged-nut-slotting-files-set-of-10/
They also do a 'saddle slotting file', which is short in length but has the correct thickness:

https://www.gluedtomusic.com/products/378/hosco-saddle-and-nut-slot-level-files-3-mm/

 

[M_Chavez]

Just thinking out loud - if I was to make my own safety files, can this be done with an angle grinder?

 

[profchris]

Just thinking out loud - if I was to make my own safety files, can this be done with an angle grinder?

I've made safe edge triangular files for luthiery by grinding the teeth off the edges. Grinding the two main faces flat would be harder work though.

 

[ChaiLatte]

If you can find a file thinner than you need, you could safety-ize it by aralditing on a strip of shim material to mask/eliminate the teeth on one edge you do not want.

It it were near the size you need, maybe just bunging up the teeth with JB Weld and then sanding the JB Weld flat would work.

A great deal depends on how you want to deal with the corners of the slot - the transistion between horizontal and vertical. Both methods above would only make one of the corners square at a time - you would have to reverse the file regularly to deal with the other corner.

Another possible place to look is a power hacksaw blade. By nature, they only have teeth on one edge, but often they have a wavy set to them. They are also relatively coarse. They are easy enough to tune for kerf width using a belt sander.

 

[M_Chavez]

Thank you.

I thought about epoxy on the side, but I reckon I'll just file my way through it quite quickly and then damage the sides of the slot.

To give some background, I am looking to cut reasonably accurate rectangular and long trapezium-shaped slots in thin aluminium (3-6mm) and brass(3mm) and need a very fine end finish. The slot size accuracy does not have to be engineering-grade precise - an error of +/-0.3mm is very acceptable and even +/- 0.5mm, while not ideal, won't be a show stopper. The sides have to be dead straight.
I have zero metalworking experience though . But I have two hands & two eyes which I hope should prove sufficient for the job after a bit of practice.

An idea of getting a mini mill like the Axi SX1 that's currently on discount has crossed my mind, but the mill won't leave a square corner, would it. So I'll need to hand-finish the ends of the slots. And, without proper tooling this will ruin the milled surface on the long edges.
Laser cutting makes a pig's ear out of the edges and is only suitable for the initial rough hogging out of the material. Same can be achieved with 2 drill holes and a jeweller's saw.
CNC machining comes back with astronomical quotes for what I need.
CNC punching I have never used, but I expect the finish and accuracy will be sub-standard and I'll need to hand-finish. This is cheap though, so can be a viable option for roughing the blanks.

So while I have a good choice of roughing out (where a Neanderthal approach of drilling, sawing and filing is not miles behind any hi-tech options tbh), the final shaping seems to come down to a set of safety hand files and Mk1 eyeball.

Am I too daft to think that 15 minutes on a flat surface with sandpaper & some elbow grease will reduce the smooth cut of a file's back to nothing? A cheapo diamond honing plate maybe? Or is it an hour's worth of work per file & a ruined diamond plate?

I can also put some sandpaper on the Axi drum sander thingiemajig for the pillar drill, clamp a fence next to it and use it as an improvised mini-thickness sander drum...

Basically, I am completely out of my depth here, so I'd welcome any suggestions.

 

[M_Chavez]

An update in case anyone is looking for similar tools:
Easiest thing turned out to buy some Bahco warding & engineering files (£7-£12 each) and bump the offending edges on a bog standard 6" bench grinder.
It also helps to kiss the safe surfaces on a diamond plate after grinding to bump the remaining high spots.

After 2-3 hours of work (got to be careful not to overheat them) and I've got half a dozen safety files in the right sizes.

 

[AES]

Just thinking out loud - if I was to make my own safety files, can this be done with an angle grinder?

Short answer is YES! I've done it, though I always use a small belt sander (with ali oxide fine grit belt). I find it easier/more accurate than with an angle grinder, especially with a thin file.

HTH