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jerry45
01-23-2002, 10:35 PM
I'm new to use of a vertical mill and I'm going to try and machine a side plate (4" X 15") for a semi-automatic firearm. In looking to purchase some 4130 material, the question was posed "indicate which direction you want the grain". From what I can see, the side plate does not take any substantial stress other that some friction rubbing from the bolt blowing back. This plate makes up the right side of the receiver box. It is riveted to the rest of the "box". Does grain direction make a difference? Note - this item does not have to be heat treated. Thanks for any input!

Thrud
01-24-2002, 12:43 AM
jerry;

Metals generally do not show "grain" unless sectioned and treated with various chemicals to etch the sample for observation under microscope. You may be refering to the direction of milling marks on the steel - they should run in the direction of the part sliding over it to minimize friction. The surface could be polished out and then it would not matter what direction the machining marks run.

Dave

halfnut
01-24-2002, 10:14 AM
I presume the seller of bar stock asked the question? For instance if you wanted a piece 2x4x?thick, he could cut that part out of 2 or 4" bar. Rolled bar stock is a bit stronger with the grain, kinda like wood, but the difference in strenth beween the 2 dirrections is often neglegiable.

I forge my knives, I think proper grain alignment is important on something like a blade, as is edge packing.

For your application, I wouldn't worry about it.

pogo
01-24-2002, 02:10 PM
So you are working on a 1919 sideplate? Me too! Grain direction shouldn't matter a bit. I wonder why he even bothered asking.

Good luck with your 1919.

jerry45
01-24-2002, 09:45 PM
Yup! Make sure we say semiauto 1919a4. The supplier has no idea what I'm doing so he said to indicate grain direction on the 9 X 18 size. Also might try to do one in 1018 before messing up the 4130. Probably will buy the SA sear and trigger/disconnector from someone who knows what they are doing.


<font face="Verdana, Arial" size="2">Originally posted by pogo:
So you are working on a 1919 sideplate? Me too! Grain direction shouldn't matter a bit. I wonder why he even bothered asking.

Good luck with your 1919.</font>

old sass
01-24-2002, 11:19 PM
A good citizens, I hope you boys are observing all the rules laid out by the BATF, etc on dewats. Wouldn't want a fellow hobbyist in deep trouble. Regards, Tim

jerry45
01-25-2002, 08:36 AM
It has been a very educational experience working with the BATF. As you probably know, it is illegal to even POSSESS a full set of parts with which to build a fully automatic firearm. To be fully in compliance, one must modify the internals (sear, trigger group, etc) to operate only in a semi auto mode before fabricating the side plate. The side plate then is milled in such a fashion that it will only accept the semiauto parts. Once assembled, the semiauto side plate must be welded to the other parts of the receiver with "full fusion welds" so that the firearm can never be returned to a full auto gun. Just thought I would pass this on to any concerned citizens.


<font face="Verdana, Arial" size="2">Originally posted by old sass:
A good citizens, I hope you boys are observing all the rules laid out by the BATF, etc on dewats. Wouldn't want a fellow hobbyist in deep trouble. Regards, Tim</font>



[This message has been edited by jerry45 (edited 01-25-2002).]

pogo
01-26-2002, 11:08 AM
I should have been clear on that point. On other boards it is assumed that you are legal and following all the rules according to the strictest interpretation of the law. The few that suggest otherwise are trolls trying to bait someone for one reason or the other.


It is a shame that one is required to mangle every piece of the kit to follow this interpretation - modification of internals to prevent reconversion to full auto. Any conversion by a machinist could be undone by him if he desired, but laws don't have to make sense.

Destroying a bit of history, but that is what we have to do to keep it legal.

spope14
01-26-2002, 07:31 PM
As for liability of gun parts, I live near Sturm Ruger in NH. I have done much research on this subject. I am going to say this now. As for laws and such for making parts, this is not an issue for my consideration, the laws of liability for thiose using the parts is another issue. I have posted some things under "Semi Auto" thread worth looking at. It may not be pleasant for those who want to make guns or gun parts, but the normal run of the mill hobbist may want to look at things more closely than you may think.......