Thread: Pressure Fitted pins

As someone mentioned, there is a very tiny "overlap" between the hole (scales) and the pin. For a 1/16" hole (I use SI, so 1,5785 mm) You need a tolerance class of H7/r6 or H7/s6 for a tight fit. This means there is an overlap of 4...20 microns! This is the ISO standard for pres fits. (25 microns is about 1/1000 of an inch.) The next problem is: Where can You find the special tools to make the pinhole, and the rod to the exact size.

You need special tools to even measure this measurements.

So, i'm a little sceptical with this.

(I work with such little things, so i know, that for example for measuring 10-20 micron difference You need a measuring microscope.)

I don't know, for my part, I want some friction betwen the scales and the blade I.E a tight fitted blade. I belive that would be hard to achieve in this way. Also, a pinned razor can be "thightend" by pinning it a little harder while a pressfit solution, to me, only can be looser, not tighter.

My 2 cents

I'm of the same opinion as cako72.

Although a cryo-shrink fit of a pin (or other metal parts) is a good practice in many machining situations, I do not think it will work well for razors.

Most scale materials usually have the qualities of being soft, flexible and thin. None of these makes a good, secure 'bedding' for a temperature-augmented force fit.

It is again worth stressing that when done properly the traditional method of pinning a razor with little washers on either scale only introduces inward compression forces along the axis of the razor pin, but does not place any extra outwards radial force on the scale material itself.

The traditional pinning method is simple, effective and proven to last for decades if not longer. The only thing that currently makes it seem difficult to most restorers is the lack of a proper and abundant supply of rivet material and washers.

- Ignatz

why do razor scales flex?

It'd give a nice clean look if it worked, but i think you'll struggle. Getting the blade tight will be a nightmare. If it relies on a friction fit where the pin passes through the tang that will be subject to abrasion over time. I do like the idea though, so good luck!

razor scales flex because the tang is a non-constant width. Slowly open and close and watch. I THINK this might be by design as it sort of acts like a spring to resist movement, making your scales nice and tight.

The idea btw was not to find an alternate method to pinning, but rather, a way to make flush fit pins.

As Ben.mid has pointed out, it can get a nice clean look.

I have a way of doing this, take a look at this thread:http://straightrazorpalace.com/galle...-smoke-pc.html

There I have filed the pins flush with the scale material. But, the scales need to be thick enough to allow at least 1-1.5 mm of tapering to make enough "coning" of the pin. Also, this metod stresses the material a bit, so I doubt that grained materials such as ivory and bone is a good choice. Perhaps some wood spieces can be used, just test away!

how does one taper? did you use a countersink bit?

khaos;

Here is one way to accomplish what you want to do.

In the first attached image you will see the idea in the rough. Simply stated: glue in some brass inserts flush with the surface of the scales. Then, take a center drill of the appropriate size (see second photo for illustration of same) and drill almost through the brass surface plate to form the conical 'stop' hole for the peened over rivet pin. The take your ordinary drill and continue on through to make the scales ready to take the pin.

The diameter and thickness of the inserted plate need not be very great. Also, there are many materials which will lend themselves to this task, although I would tend to choose for a metal, in particular either brass, nickel silver or silver. These are soft enough to work easily, strong enough to serve for the intended purpose and cheap enough to reasonably afford. You might also choose for a hard plastic or resin impregnated substance.

This approach does require that you do a bit of careful inset and gluing work, not to mention carefully filing away the top of the peened-over pin after the hammering operation with subsequent polishing, but it will give you the effect you want.

I use exactly those bits ignatz so kindly has attached photos of, 1.6mm centerdrill. Makes a nice tapered hole.

Nice drawings by the way, ignatz, and of course that is also a way of doing it, in fact when it comes to grained materials it's probably much better also!