Author Topic: .38/.357 prototype (Read 75058 times)

Cutter · « **Reply #220 on:** July 26, 2018, 08:23:21 PM »

Profiled the Extractors this afternoon , needs the pocket

for a spring, a radius on the hook and ream the pivot hole.

Maybe tomorrow

bruski · « **Reply #221 on:** July 26, 2018, 09:43:28 PM »

Cutter,

What is the other hole for in the extractors? Also, how do you plan on cutting the reliefs in the barrel plate and barrels for the extractors? It seems every time that I unscrew the barrels then re-torque them in place the next time they are in a different position even though I torque them to the same 40 foot pounds. I guess I could lock tite them if they go past final torque.

bruski

Sparky_NY · « **Reply #222 on:** July 27, 2018, 08:54:57 AM »

Cutter, those extractors visually look to be about a 5:1 length ratio from where the spring would set to the hook. That would five the hook a 5:1 mechanical advantage over the spring. What sort of spring do you plan to get enough down force at the hook?

(I too am curious about the extra hole.... expect its for fixture purposes) What is the thickness/width of them?

Cutter · « **Reply #223 on:** July 27, 2018, 12:08:59 PM »

Both holes are .086 in the picture, used for clamping

with 2-56 screws when cutting profile.

Iâ€™ll open the pivot hole to .094

The ratio is 2.379:1

Spring .156 OD X .023 wire X .19 long

4 coils, two active with .054 travel rated about 85 lbs

Flat stock material, oversize 3/16 which came .206 thk.

.250 wide at the hook X 1.675 long

Bruski,

I havenâ€™t anticipated any problem until now.

I think with a good square thread relief and mating surface

it should be solid and repeat ?

Cutter · « **Reply #224 on:** July 27, 2018, 07:21:17 PM »

All finished , except for H.T.

Cut the pocket in the bolts next

Cutter · « **Reply #225 on:** July 27, 2018, 08:26:19 PM »

Bruski,

Most of the time I use Mitutoyo 8â€ dial

I have some 1/4 â€œ O1 drill rod for firing pins

It\'s been leaning in the corner for years

Bruski,

A more accurate way to check lengthâ€™s

bruski · « **Reply #226 on:** July 27, 2018, 10:52:17 PM »

Cutter,

Thanks for the information about measuring down to a millionth. Your extractors are looking great also.

I had a successful test firing of a freshly primed brass in one chamber. The extractor seems to let go of the brass just as soon as it clears the chamber and ejecting by itself without any help. I would assume this would get even better with recoiling going on at the same time.

bruski

Cutter · « **Reply #227 on:** July 28, 2018, 10:15:14 AM »

Cutter,

Thanks for the information about measuring down to a millionth. Your extractors are looking great also.

I had a successful test firing of a freshly primed brass in one chamber. The extractor seems to let go of the brass just as soon as it clears the chamber and ejecting by itself without any help. I would assume this would get even better with recoiling going on at the same time.

bruski

Thank you bruski

You are always coming up with some great ideas.

I would like to see your new firing pin.

Iâ€™m holding off on mine until I determine the hammer stroke

I see you havenâ€™t decided on the followers yet, or are you planning

to use a new Flux Capacitor ?

Also Bruski , Happy Birthday young man !!

Sparky_NY · « **Reply #228 on:** July 28, 2018, 12:26:49 PM »

Bruski\'s bitthday? OK, strike up the band ! Happy birthday to the big B

Sparky_NY · « **Reply #229 on:** July 28, 2018, 12:28:54 PM »

Bruski,

A more accurate way to check lengthâ€™sre

Great idea Cutter, thats why we pay you the big bucks ! LOL What I like about that method is that you can also sweep the follower pins to be sure they are all spaced the same from the back of the bolt, thats just as important as the overall length.

bruski · « **Reply #230 on:** July 28, 2018, 05:46:06 PM »

Hey everybody,

Thanks guys for the Birthday greetings, I been eating all day so far at the different restaurants around town that offer free meals on your birthday.

Here are some pictures of the firing pin used in the test firing of a primer. It is made up from the 10-32 x 3 inch socket head screw with a 10-32 stand off as a coupler attached to a piece of 3/16 drill rod threaded on one end and turned for the cartridge end. The bolt and bushing on the rear end is drilled and tapped for a 10-32 set screw to hold it in place.

The dent on the primer looks good and deep enough for successful firing. It is adjustable being threaded into the stand off. The extractor part number is Brownells 430-000-249 and does work ok but is a little blunt on the forward end making it hard to snap over the rim. A little grinding and filing fixed that with more of an angled ramp.

Cutter, I plan to mark and drill the bolts with the cam installed and with a cartridge chambered on BDC in the firing position. The cam that I used on the prototype basically surrounds the entire bolt carrier and I will probably use it on this gun.

bruski

bruski · « **Reply #231 on:** July 28, 2018, 05:47:22 PM »

The extractor used.

Cutter · « **Reply #232 on:** July 29, 2018, 12:48:09 PM »

Thanks to everyoneâ€™s input, Iâ€™ve come up

with this simple firing pin for my bolt

The mean is set at .040 projection

Cutter · « **Reply #233 on:** July 29, 2018, 02:15:37 PM »

Iâ€™m just trying out a GoPro Hero4 ,

My grandson gave to me

https://www.youtube.com/watch?v=xilS7B5y3Cc\' title=\"https://www.youtube.com/watch?v=xilS7B5y3Cc\">https://www.youtube.com/watch?v=xilS7B5y3Cc

Sparky_NY · « **Reply #234 on:** July 29, 2018, 04:25:42 PM »

Thanks to everyoneâ€™s input, Iâ€™ve come up

with this simple firing pin for my bolt

The mean is set at .040 projection

Almost identical to what I ended up with. Only real exception is I used .188 drill rod for the full length (except the short 1/16 section at the very end). The .188 rod lets me use the common .300 OD springs. I have some left over from the 22 gat that I will use for first trys. I was debating how to attach the hammer section, pinning it is a good idea, I was thinking silver solder but now have to rethink it.

bruski · « **Reply #235 on:** July 29, 2018, 06:02:11 PM »

Hey everybody,

I decided to run one bolt through the cycle so I marked drilled and tapped one bolt for the cam follower pin and installed it. The bolt cycled all the way to about the 5;30 point where the firing pin spring ran out of travel, bummer. :-| I removed the bolt and am in the process of shortening the rear bushing a little and unscrewing the sear hammer 10-32 screw a little to get a little more travel. Hope this gets the job done. ::

In case anybody is wondering, I am using the frame, cam, cocking mechanism and crank set up from the prototype at the beginning of this thread.

bruski

Sparky_NY · « **Reply #236 on:** July 29, 2018, 06:57:11 PM »

Hey Cutter, you should send those extractors to Bruski for heat treat. He can leave them on the porch overnight and ship them back.

Cutter · « **Reply #237 on:** July 29, 2018, 08:47:42 PM »

Hey Cutter, you should send those extractors to Bruski for heat treat. He can leave them on the porch overnight and ship them back.

Bruskiâ€™s weather might light this candle

bruski · « **Reply #238 on:** July 29, 2018, 09:05:06 PM »

Hey guys,

The temperature only got up to about 105 today, it felt kinda cool outside to me.

Cutter, your extractors are looking great there holding the cartridges nice and tight to the bolts.

The spring travel problem is cured and I fired a few primed brass through it with good results all the way around. The brass all ejected themselves at about the 9 o- clock position just as they cleared the chamber. Don\'t want to try any live rounds until heat treatment on the bolts is done.

bruski

Cutter · « **Reply #239 on:** July 29, 2018, 09:18:26 PM »

Hey guys,

The temperature only got up to about 105 today, it felt kinda cool outside to me.

bruski

Hey Cutter, you should send those extractors to Bruski for heat treat. He can leave them on the porch overnight and ship them back.

OK Guys, back to plan A

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Author Topic: .38/.357 prototype (Read 75058 times)