Author Topic: .38/.357 prototype (Read 75040 times)

Sparky_NY · « **Reply #100 on:** June 28, 2018, 04:38:59 PM »

Sparky,

That is the prototype bolt design with a heavier firing pin and a rear cam follower. The slot for the ejector pin is not milled yet or the cam follower milled yet as I am waiting for the Enfield firing pins to arrive first. The flats on the forward end of the bolt are closer too 2.200 inches long instead of the 2 inches in the picture description.

bruski

Misunderstanding, I mean the bolt from the prototype gun that you have already fired.

Roller · « **Reply #101 on:** June 28, 2018, 06:37:57 PM »

Is that you with the youtube video of one on a D&E? Do you have any drawings or further info on yours?

Not me, but that video inspired me to make a Bruce Feed for my gun. Will have to post a photo of it.

Frank

Cutter · « **Reply #102 on:** July 02, 2018, 03:59:26 PM »

An IGS or Parasolid model is available for you

guys with the applicable software.

Just message me

RumRunr · « **Reply #103 on:** July 03, 2018, 04:32:02 AM »

Thanks Cutter, it is much appreciated.

Sparky_NY · « **Reply #104 on:** July 03, 2018, 10:58:47 AM »

I am using Fusion 360 and am having problems getting Cutters files to import correctly. I get faces instead of bodies and other funnies. Anyone else having similar problems? (what file format are you getting from Cutter?)

George

bruski · « **Reply #105 on:** July 03, 2018, 06:12:44 PM »

Sparky,

The files that cutter sent to me are .igs files. My BobCad software wanted to open them after download but I right clicked on the file and then went to properties and changed the opens with section to the Fusion360 software. My Fusion 360 for some reason takes a while to open when I need it. You might need to right click the bottom left corner of your monitor and click on task manager and close or end all fusion 360 tasks.

I received the Enfield firing pins and they are more work then was thought when I ordered them. Not worth the time to rework them.

bruski

Sparky_NY · « **Reply #106 on:** July 03, 2018, 06:57:18 PM »

Sparky,a

The files that cutter sent to me are .igs files. My BobCad software wanted to open them after download but I right clicked on the file and then went to properties and changed the opens with section to the Fusion360 software. My Fusion 360 for some reason takes a while to open when I need it. You might need to right click the bottom left corner of your monitor and click on task manager and close or end all fusion 360 tasks.

I received the Enfield firing pins and they are more work then was thought when I ordered them. Not worth the time to rework them.

bruski

I get the file imported into fusion and see it on the screen. The problems are that they are not solids, only a bunch of surfaces, nothing fusion can work with. Import a Cutter file into fusion and see if you can \"inspect, measure\" a circular OD for instance. It give me perimeter rather than diameter, does not recognize it as a circular diameter.

bruski · « **Reply #107 on:** July 03, 2018, 11:58:44 PM »

I can\'t seem to measure anything with fusion, but I am new to this software and might be doing something wrong.

bruski

RumRunr · « **Reply #108 on:** July 04, 2018, 02:08:32 AM »

Might have to go into options and get it to a solid or wire frame

Sparky_NY · « **Reply #109 on:** July 04, 2018, 06:14:54 AM »

I can\'t seem to measure anything with fusion, but I am new to this software and might be doing something wrong.

bruski

You are not doing something wrong, its the file. Measuring is one of many things you won\'t be able to do with the file.

Sparky_NY · « **Reply #110 on:** July 04, 2018, 11:16:38 AM »

Might have to go into options and get it to a solid or wire frame

I am assuming that is a guess, there are no such options in Fusion 360. What kind of cad/cam do you use? Have you successfully imported a step or igs file from Cutter and tried to measure features and apply tool paths? The devil is in the details, the files import but not in such a way to make them really useful in Fusion 360. I strongly suspect solidworks would have the same problems with these files.

RumRunr · « **Reply #111 on:** July 04, 2018, 04:15:06 PM »

I have fusion as well but work in a machine shop also so I use professional software and I can grab info from files.

I will see if I can get time to get things figured out

bruski · « **Reply #112 on:** July 08, 2018, 12:22:27 AM »

Well, scratch that bolt length that I posted of 4 inch long. The bolts have to be at least 5 inches in length with about a 4.625 long carrier if 2 inches of the carrier are used for the pan section. The flats on the bolt could be 2.100 inches long with a 2 inch pan. I am not sure what the dimensions are on cutters carrier and bolts but the bolt circle could be 3.250 like my prototype. The rear section of the carrier is 4 inches on my prototype and will work fine with the new .750 diameter bolts on a 3.250 bolt circle.

I am waiting on a hunk of 4 inch brass rod for the carrier (over $300.00) can you believe the price of brass now a days. I have only one chance to get it right the first time with the brass so I am sacrificing the aluminium one to test before cutting the brass. This sucker is going to be a heavy beast to move around.

bruski

Cutter · « **Reply #113 on:** July 08, 2018, 10:11:26 AM »

Bruski

For what itâ€™s worth,

We are working with a 2.250 BC , 2â€ long pan , 3.375 diameter X 3â€ long bolt carrier.

2.100 bolt/cam stroke

bruski · « **Reply #114 on:** July 08, 2018, 02:06:29 PM »

Thanks cutter, I think that I will try mine with a 3.25 bolt circle so I can use the barrel plates and box cam and cocker from the prototype to save some work and time. It is going to be heavy no matter which way I go any way.

bruski

bruski · « **Reply #115 on:** July 08, 2018, 02:10:28 PM »

Cutter,

You mentioned that you are going with a 2 inch pan and using a 2.100 stroke. How are you going to get the bolt flats to smoothly enter the flats on the pan? Or is your bolt stroke over shooting the front of the pan into the chambers a little?

bruski

Cutter · « **Reply #116 on:** July 08, 2018, 02:27:29 PM »

The Pan runs in the Carrier .250

Sparky_NY · « **Reply #117 on:** July 11, 2018, 01:15:42 PM »

Hey Bruski...

Cutter and I are homing in on a bolt design and are now looking at the firing pin / striker. Need to get some idea of what would be a working combo, spring specs etc.

Can you post a idea of your hammer and firing pin specs along with the specs for the spring you used? It did detonate the 38\'s so its a good data point.

Would be interested in what you are using for your new bolts you are presently making also.

(the 4140 prehard 3/4 stock came today for the bolts ! )

Thanks!

George

bruski · « **Reply #118 on:** July 11, 2018, 11:20:27 PM »

Hey sparky,

The old bolts use a 10-32 x 3 inch long socket head screw for the hammer with a .300 x .041 x 2 inch compression spring which fits over the socket screw perfectly. The end caps are made from 3/8-24 x 1/2 inch long grade 8 bolts. The spring is held in place with a 10-32 x 1/2 inch long standoff screwed on all the way so the end is nice and flat for striking the firing pin. The firing pin is made from ejector mold pins used in the plastic molding industry part number PE1-062L6 from plastixs.com.

The picture of a newer style bolt is close to what I will use , just add an inch to the length to make it 5 inches long. The firing pin is a reworked Enfield rifle pin turned down for the same spring as in the other bolt design. Not sure if I will thread the end for the sear catch or try something else.

The bolt material that I use is just oil hardening drill rod. The only portion of the bolt that I harden and temper is the rear end of it for the recoil plate. The end caps on the new bolt will be a sliding fit into the bolt then cross drilled for a roll pin to hold it in place. It will not absorb any recoil at all.

bruski

bruski · « **Reply #119 on:** July 11, 2018, 11:22:22 PM »

Another picture of the new bolt design.

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Author Topic: .38/.357 prototype (Read 75040 times)