Re: Bell cap how to

[Magnus]

Matt.

These diameters that you mention are of course the inside edge of the countersink that has been punched into the dome, the other being the bottom edge of the dome itself. Where I have said that the countersink hole is punched on a dome shaped former this tends to keep the inner edge of the countersink just above the lower edge of the actual dome.

But again, the only way you know this is by modern reconstructions which you have made, as well as jurjen. We can't measure the originals...so we're agreed on that. Also, What do you think the difference is in height, if the outer edge is flat on a surface, and the inner is, as you say raised? Small enough that it's a negligable amount?

When we use them with a rivet or an integral stud on a beltplate the bell-cap, or domed washer, or whatever else anyone would wish to call it, is not yet put on until belt leather is firmly put against the belt plate.
This is done by tapping the leather down with a tube or punch with a hole in it until it sits firmly on the beltplate, in the case of a rivet it's head would be sitting on a rivetting dolly with an integral stud this would be on a firm block with a piece of leather between the plate and block.

I use masking tape to secure my plates to the leather. Works great.

It is then that the bell-cap is put over the rivet or stud then with our tube or open punch this is also tapped down against the leather, I should stress very gently just a simple tap which helps the cap to just bite the leather.
This way there is going to be no bounce or movement whatever of anything, the excess of the rivet or stud is now cut off at around a couple of mm above the dome then very gentle tapping is done which spreads the rivet end into the countersink.

Gotcha. Thanks for explaining how the process works, although really it's the same as using a regular washer. So much so that I'd say they are both washers and essentially serve the same function.

The inner edge of the countersink is now of course also down onto the leather but not severely, it is the gentle peening which locks the rivet or stud and only on estimation I would say of only about 10% of the poundage needed for a flat washer.

I disagree with this. What makes you think that there is any less force required to peen a rivet for a bell cap washer vs a regular washer? The hole diameter is the same on a bell cap washer (rivet shank diameter) as it is on a regular washer...so...the only amount of "poundage" required is the bare minimum needed to expand the shank past that hole diameter. I can gently tap a copper rivet with the best of them, on just about any surface...I don't require a bell cap washer to make my peening job easier. In fact, if required, I'd rather mushroom the shank out more to deter failure (seperation of materials), more so than can be done on a bell cap washer, since the raised sides could interfere with the mushrooming. Or it will get crushed.

Which brings up another point...these have only been found on belts and belt components right? Seems to me then that it would make more sense that they're used in cases where the peened end of the rivet and a square washer may get snagged on clothing (important clothing that is), and slowly damage it over time. Otherwise, why don't we see these on the inside of segmentata? The plates rub up against the subarmalis...so to me it doesn't really have anything to do with less stress, as it does garment protection.

There is far less poundage in peening and the decorative plates become less damaged

Could be a case of hulk-hand...I've never had issues with peening my belt plate rivets, nor have my belt plates ever been damaged due to riveting them to the leather. And trust me, I am no craftsman! lol. I tend to put 5 oz leather under my rivet head when I'm doing rivetting on a surface that could get scratched anyway. Works fine...sure don't need any bell cap washers.

, and also less snagging of things under the belt or whatever they are used with. The whole concept of these things is to create less stress and damage.

Less stress? I think we'll have to agree to disagree on that one. Less damage on garments, we're in full agreement!