Making a testing weight

[Nolano]

I'm an epee fencer learning to do armoring, and so I've been collecting the tools that I need.
Looking at test weights, they tend to range anywhere from $20-$40, and that seems kind of ridiculous for someone like me.

I'm somewhat of a machinist student, and have full access to a lathe, as well as CAD software which I have already used to figure out almost exactly the size the weight needs to be. In my design, it's 1.25" in diameter, 5.25" long, with a 1/2" hole bored 3" deep. This leaves the weight at about 770 grams, just enough that from there, small amounts of material can be taken off until it is precisely the right weight.
I've noticed that a lot of test weights have plastic lining the inner hole... Is this something I should worry about adding?
Is there anything else I might have missed?

[brtech]

All weights have an insulated bore, which prevents the tip from shorting to the barrel. If you are only testing epee and you are the only one who will use the weight, and you only use it on a test box, you can get away without insulation because in epee, the switch doesn't connect to the barrel. A tester will show a B-C short, but you can ignore it. On a foil, you must have an insulated bore, because the barrel is part of the switch circuit. If you want to make a two part weight and use it to test foil as well as epee, or you want someone else to be able to use your weight, or you want to test on a machine, then you will want to insulate the bore. There is a thread on that subject going on now.

If the weight is 750 grams, and it fits on the epee, that's all that matters.

[Purple Fencer]

Don't make the weight tall and skinny...it will tend to lean against the blade and may bind up if the spring is right at the edge of passing.

[Nolano]

Thanks for the advice.
I can make it out of a larger diameter stock, as well as find a way to insulate the bore... I might be able to make a press fit plastic sleeve for it..

[SJCFU#2]

Originally Posted by Purple Fencer

Don't make the weight tall and skinny...it will tend to lean against the blade and may bind up if the spring is right at the edge of passing.

Actually I prefer long, skinny weights such as the Leon Paul over short, fat weights such as the Tripplete or many brass weights - especially for combination weights where the 250 gram section goes on top. Shorter weights obviously have a shorter bore and when you put a lot of extra weight on top the center of gravity moves up close to the top of the bore so the weight is more prone to wobble atop the tip while testing (stability tends to be a big thing for me = probably has something to be with being a naval architect).

BTW the tolerances for weights are +/- 2 grams for 500 gram foil test weights and +/- 3 grams for 750 gram epee test weights (both of which are actually pretty large compared to most other test weight)

It may also help to read this thread on lining epee weights (assuming you haven't already).

[Nolano]

Well, it's done. It weighs in at 751 grams, has insulation in the hole, and looks very professional.
Total cost: $2
Total Time: 1 hour(it would be much faster if I made another)

[FoilyDeath]

Ever thought of starting a weight selling business? :P