saws in fine holes

In article , David writes

Dave,

Is this what you are looking for? The best such files are from Switzerland, and Vallorbe is one of the premier names. Google "Vallorbe Swiss files" for more suppliers.

You could try looking over at Cookson Gold:

As I understand it a "Piercing saw blade" is held via clamps. This allows the blade to be thread through a hole before clamping in the frame. A fret saw blade has a pin at each end to allow it to be held in slots in the saw frame. I would always consider a fret saw to be a wood working tool and a piercing saw a metal workers tool.

Therefore you need piercing blades. (And a frame)

Re the file. I would just grind down a flat Swiss file to suit.

They're quite different.

Both piercing saw blades and fret saw blades are clamped in their frames although the frames are different, the piercing saw frames are more rigid than the fret frames.

The saw blades I think you mean that have pegs to hold the blades are coping saw blades.

Shucks, brain in Neutral! Thanks for the correction.

Some powered fret saws (called scroll saws in US) also have pinned blades.

BugBear

I've seen "escapement makers file" in watchmaking texts generically applied for a fine cut file of small section (usally about half the size of the generic needle files and much finer cut). On the same subject it seems to be very difficult to find number 8 cut files and they are very useful indeed and while I have a resonable collection of second hand ones I don't have some useful shapes which I would like to purchase.

However for your problem, I think I would probably use a slitting saw as a viable alternative for cutting your slot as it will make sure it is straight and do it in a fraction of the time. If the part is very thin you could consider soft soldering it to a larger piece of brass, or if it is very small and delicate using shelac.

Alan

Hi Alan,

Can't use a slitting saw... it is a 1/8" x 20swg hole. The text with the drawing says to drill a 0.9mm hole, use the saw to expand the hole then an escapement file to square it up.

Best regards, Dave Colliver.