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Bolt Machining Process


Topic:



Topic author: seinen
Subject: Bolt Machining Process
Posted on: 11/23/2006 12:37:59 PM
Message:

Here are the drawings of the training rifle bolt machining process I promised to post in another thread. I took these drawings from a trade bulletin from the "Nippon Hyoteki Shokai" company.

The first set of drawings shows the succession of machining steps used to produce the bolt, striker, and safety knob for a T-38 training rifle the company once sold. Apparently, the bolt was machined from a single piece of stock.
http://forums.gunboards.com/attachment.php?attachmentid=11199&d=1192052834
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For general interest, I've also included a second set of drawings that shows the machining steps this company used to produce their T-38 training rifle receiver.
http://forums.gunboards.com/attachment.php?attachmentid=11201&d=1192052851
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C/

Replies:

Reply author: fredh
Replied on: 11/23/2006 2:47:20 PM
Message:
Chip, looks like they made the bolt from a thick piece of plate. I'm guessing they used something like a DoAll to cut out the semi-finished shape to minimize set-up and turning time on the lathe. They could have milled away the extra material, but that would have taken too much time. It wouldn't be done that way today. Thanks for posting those pictures. I wish I could find photos like that from the arsenals. Professor Tani worked in the machine tool area during that period and told me a lot of stuff, but a picture is worth a thousand words. When we sat down to talk back in the '80's, he asked if I'd ever seen a set of the '03 Springfield process sheets. He had had an original copy of the sheets but lost them in a house fire. I gave him my reprint of the sheets, and he couldn't believe stuff like that was still around. At the time he was setting up a museum in Tokyo on this subject, and the process sheets became a part of the museum. Why am I rambling like this? The process is frequently as interesting as the product.

Reply author: seinen
Replied on: 11/23/2006 7:41:26 PM
Message:


Fred,

Yes, when I was offered a copy of this catalog in 2002, I jumped at the chance. I'd never seen exemplified steps in the manufacturing process for any Japanese rifle parts before and this was really a great find. I'd sure like to know if military rifle receivers and parts were fabricated in this same way.

C/

Reply author: fredh
Replied on: 11/23/2006 8:07:08 PM
Message:
Chip, in the 1st edition of MROJ I reproduced a photo of a stack of forged receivers at Jinsen Arsenal. Don't remember if that photo made it into the 2nd edition, but it's not there now. I've seen a photo of a forged T99 bolt, and it was as close to net shape as they could get which wasn't very close at all.


Reply author: 03man
Replied on: 11/23/2006 9:40:37 PM
Message:
Very interesting, thanks for posting.


 

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Prints on O3

I have a book with all the prints, set ups and machinery needed to make Springfield rifles. Very interesting. These prints are interesting too. riceone.
 

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I have a book with all the prints, set ups and machinery needed to make Springfield rifles. Very interesting. These prints are interesting too. riceone.
Are the photos of good enough quality to post some here? Would like to take a look if so.

C/
 
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