Need a little Eng. help on this, Reg’d air spacer thread
I am trying to I.D. this thread so I can save a few bucks having a couple of these made. For O.G. and my .257 Edgun projects. Should be a lot cheaper than buying 30 cal. regs. to get this 1 simple part. The male end is 28mm O.D. and is measuring about .75mm to .80mm between thread peaks. I am not sure how Metric threads are pitched ?? Is anyone here familiar with them. I found charts that list 28mm x 1, 1.5, and 2 as some what common.
FYI: this is the Regulated Air Space, spacer to give more area, Ed made for the 30 cal. Edguns.
Thanks, Doug…
All Replies
Viewing 11 replies - 1 through 11 (of 11 total)
Hey Doug, I am glad that the ass backwards way of doing the measurement worked for you!
Wanta: you need to buy a better metric thread gauge! My Starrett metric thread gauge has a .80 mm pitch on it. It has 28 gauges on it that start at .25 mm pitch and it ends at 2.50 mm pitch.
English measurements are so much easier! Don’t for a minute believe Sir Ville about the metric system being superior! Believing anything that Sir Ville says will only cause you a lot of trouble and strife in the long run! 😯
If you don’t belive me; just ask HOOT!
I got that backwards. I explained it right, but had the words wrong. Millimeters per pitch was you know. Hvent had much time to look. But I still haven’t found anything showing a .8 thread pitch. Could it be a pipe thread or something?
I was able to use Wanta’s idea to confirm the pitch at .8mm
I don’t have a .8 on my thread gauge. .7 , .75, and .90. No .8. Now, that doesn’t absolutely mean it doesn’t exist. But I’d try looking up a metric thread chart.
P.s. if your going to be doing much thread work. Just buy a gauge. I don’t think they are expensive and most tap sets come with one.
Well explained ! That´s the trick they teach to mechanics and such over here.
Metric is the way, OG. Metric – no Imperial medieval units – just Metric. :butkick:
Hi Doug.
Sorry that I didn’t have time to call you tonight. It was stupid busy at work.
I just measured my spare 22 cal regulator housing’s end threads and the thread size is 28 mm OD X .80 mm pitch.
It took me quite a while to be sure on the .80 mm pitch. I had to use my jeweler’s hood and my Starrett metric thread gauge to come up with the .80 mm pitch measurement. It was really hard for this half blind oldgoat to be sure if the pitch was .75, .80 or .85 mm!
This metric shit is just so fucked up! Ed should just go the extra mile and make his guns with English measurements! Life would be so much easier! 😆
I do know that my 22 cal regulator housing is the same OD and pitch size as my 25 and 30 cal housings. The 22 cal regulator end will screw into either the 25 or 30 cal air valve/regulator assembly and replace the 25 or 30 cal regulator.
I measured with calipers under magnification but your idea would be unrefutably accurate, thanks
Threads per mm is how you measure metric. You could either use a thread gauge to confirm or set up something to measure how far it travels per turn. Take a overall lenth measurement, make one full turn and take another measurement. Kind of over complicated way of doing it. But its a last resort kind of thing. I thing I’ve seen .8 per pitch before but it could have been a misread of .75. As far as volume goes. I figure Ed over did it a bit. I filled mine with orings to try to get an extra shot or two per fill and it had zero affect on power at 880 fps with jsb.
I found the technique for metric threads pitching and it is peak to peak or valley to valley as I read it. So this looks like 28mm x.75 threads unless someone else here knows otherwise.
Ed added .590″ to the regulated airspace in the 30 calibers to shoot the 44.75 grain Jsb’s and we are likely to end up at 50 to 60 grain with the .257 cast bullets and possible want to shoot higher FPS, so do you think I should go up a bit more maybe .750″ or a bit more ???
Viewing 11 replies - 1 through 11 (of 11 total)
- You must be logged in to reply to this topic.
Yes, my set isn’t that great. Like I’ve said before, I wasn’t a machinist. Just an R&D mechanic with access to machines. When I came to cutting threads, I either used out Onsite instructor, or found something threaded and welded it to the work piece. We didn’t have the high end threading tools so it was a lot of figuring out rotation speed vs tool travel speed.
What I mean as far as finding any info on .8 pitch. I don’t see where it is actually in use. Like available tooling. Fuck does Ed like to use the most off the wall shit. Just like the actual breach Oring size for 25 cal is some crazy shit like 6.3×1.6. Good luck finding that anywhere else.