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Re: machining question / BIT

Posted: Fri Jun 16, 2023 6:59 am
by HTRN
Precision wrote: Fri Jun 09, 2023 11:55 am That is a good idea, except grade 5 titanium is hugely expensive except from the place I get it.
Who said anything about titanium? Use perforated 304 stainless. It will be half the weight of solid sheet and vastly cheaper than titanium - a .048 thick sheet of SS with .125 holes, 4'x4' is $570 from McMaster and has a 40% open area.

Re: machining question / BIT

Posted: Sun Jun 18, 2023 4:23 pm
by Precision
Cobar wrote: Wed Jun 14, 2023 5:24 pm In this video they are talking about arrow tests but you can see some results on the breaths of a helmet.

LINK

that part starts just after 40 minutes.
very nice on topic video

Re: machining question / BIT

Posted: Sun Jun 18, 2023 4:24 pm
by Precision
HTRN wrote: Fri Jun 16, 2023 6:59 am
Precision wrote: Fri Jun 09, 2023 11:55 am That is a good idea, except grade 5 titanium is hugely expensive except from the place I get it.
Who said anything about titanium? Use perforated 304 stainless. It will be half the weight of solid sheet and vastly cheaper than titanium - a .048 thick sheet of SS with .125 holes, 4'x4' is $570 from McMaster and has a 40% open area.
will look into that, thanks

Re: machining question / BIT

Posted: Sun Jun 18, 2023 5:07 pm
by Precision
HTRN wrote: Fri Jun 16, 2023 6:59 am
Precision wrote: Fri Jun 09, 2023 11:55 am That is a good idea, except grade 5 titanium is hugely expensive except from the place I get it.
Who said anything about titanium? Use perforated 304 stainless. It will be half the weight of solid sheet and vastly cheaper than titanium - a .048 thick sheet of SS with .125 holes, 4'x4' is $570 from McMaster and has a 40% open area.
https://www.tigertitanium.com/storek/Plate/6Al-4V

4 plates of 12x48" is $155 each so $620 total. It isn't vastly cheaper, but it is when you consider the time element of making the holes.

Re: machining question / BIT

Posted: Mon Jun 19, 2023 10:34 am
by Precision
The other thing,
The stainless for a 12x12 section at .036" thickness is 1.47# without holes. Is .882# with the 40% hole option. The TI without any holes is .845#

This means there is zero weight advantage to using the perforated stainless.

I may buy some of the perf non-stainless to do testing with and compare to the same steel that is not perforated then I can extrapolate what should happen with the TI. So thanks for making that suggestion.

If I did the 40% holes in the titanium, it would be .507#, which is a significant reduction

Re: machining question / BIT

Posted: Fri Jun 23, 2023 1:11 pm
by Combat Controller
What tooling do you have? Would you be able to add Scandium Alloy or Aluminum?

Re: machining question / BIT

Posted: Wed Jun 28, 2023 7:58 pm
by Precision
Combat Controller wrote: Fri Jun 23, 2023 1:11 pm What tooling do you have? Would you be able to add Scandium Alloy or Aluminum?
7071 aluminum is about the same strength (my very amateur research) as grade 2 TI, but it galls much easier and thus would wear out faster. Don't know anything about scandium alloys other than some smith revolvers used them.

As a reference grade 5 TI is +150% stronger than Grade 2 in all fronts and about 60-80% stronger than grade 4 TI. Which is why I am using 0.8mm Grade 5 where others use 1.0mm grade 4. 20% lighter and damn near the same protection. Provides less fatigue and less heat build up so you fight better, stronger and faster.

Re: machining question / BIT

Posted: Sat Jul 08, 2023 9:17 pm
by Combat Controller
Hmmm