A couple of months ago I did my easiest build ever.  Over on gunco.net we used to talk about using "type U drive screws" to do a build, but no one ever got around to doing one that I know of.  Well a couple of months ago I got access to about a dozen of the drive screws and I had a kit at home unbuilt so I said "what the hell" and went to work.  All it involved was grinding the rivets flush and drilling the appropriate size holes then pressing the drive screws into the holes.  No headspacing, pulling of the barrel or removing the rivets.  I used the drive screws for 4 of the trunnion holes, the center support, and the rear tang.  I did end up using screws for the 2 rearmost trunnion holes because I removed the rivets and the holes were too big for the drive screws I had, but I am sure I could have used drive screws if I had bigger ones.  Yesterday I finally got the opportunity to test fire the build and it ran like a clock.  I fired about 300 rounds through the rifle with no adverse effects on the drive screws.  This would be the ideal build for guys with limited tools.


ETA   When I did my build I removed the receiver stubs from the trunnion, tang and trigger guard.  After removing the receiver stubs I simply ground the rivets flush with the trunnion and rear tang, marked center of the rivets and drilled holes for the drive screws.  I determined the size hole I drilled by measuring the small end of the drive screw and using the appropriate size drill.  I believe the drive screws I used were a #10, but I don't remember the size hole I drilled.  For the rear tang I used the drive screws full length, but for the trunnion I ground them off to about .240" because the holes I drilled were only .244" and the drive screws were .250".  I then put my parts into my receiver and used my hydraulic press to set the drive screws.  The reason I used my press was that I was afraid that I might start one crooked or wreck something swinging a hammer, although I am sure you could use a hammer if you were careful.  I could only use 4 of these on the trunnion because after I ground the 2 rearmost rivets flush I pushed the rivets out and my drive screws weren't big enough to use on the holes left so I used some grade 8 10-32 screws I had left over.  For the center support I used my usual length of 1/4" stainless tubing and drove a drive screw into each side to hold it in place.  For the trigger guard I used nuts and bolts.

Interesting. I have never heard of "drive screws" before. So you just used your press and pressed them in huh? Are these "drive screws" available at any hardware store?

BTW, nice AK!!

I got them as "left overs" from a project at work, but when I googled them I found them on www.milspecfasteners.com.  There are other suppliers too.  Just google "type U drive screw".  The only reason I had never bought any before is because all the suppliers that I contacted only sold them in large quantities.  

Could you use a bench vise to press them in?  Pretty cool idea.

You could use a hammer to pound them if that is what you had.  

Looks good Dale...

Wow, thanks for the insight on another build method.  I did a search on McMaster-Carr's website and found out that they carry the U-screws.

Groupbuy through midwest armory  

Hmmmmm....

What is the usual usage of these fasteners?

How tight do these hold?  Would they need to have a dab of loc-tite?

Before I did my build I tested one on a piece of I-beam in my garage.  I used one to attach a piece of receiver stub to the beam and I couldn't pry the drive screw out with a screwdriver.  I think that these will certainly survive the tensile forces on them in an AK build and as far as shear forces, the shear forces on AK rivets are negligible.

Tag

OK let me see if I understand what you mean:

-are the sheAr forces those which go against the long-axis of the screw? In other words, side-to-side?

-are the tensile forces the ones which act on the long-axis, attempting to move the screw out of it's hole in the opposite direction it was driven? In other words, in-and-out?

I am not an engineer, so these words cause confusion for me.

How many other people have tried this? It certainly seems to have potential...

And you haven't been blown up yet, which is nice

Edit: we're dealing with metal and not lingerie aren't we?

Can you guys post some web sites that sell these ...thanks

Are these made of aluminum or steel?  Either way, I would be interested in building an AK using these and then shooting the piss out of it to see how long these will last.

I suspect they will outlast me.

Do they rotate as they are pressed in?

WinnR on gunco.net has done a few and he has a friend who has put thousands of rounds through his drive pin build with no problems.

The pins I used were grade 8 steel.  And yes they did spin as I pressed them in.

Shear forces are forces across the axis and tensile forces are the forces trying to pull the screw out.

if it's a stupid idea and it works, it ain't stupid, right?

Tagged, very interesting

Where can i buy some of these?

Wow, this gives the authentic rivet look without the rivet hassle.

What size do you use and will these work

www.hansonrivet.com/w58.htm

How about this company again what size do you use
www.fastenal.com/web/products.ex?N=999600056&Nty=0

Very cool.  Some good specs I found:
http://www.americanfastener.com/fasteners/selftapping.asp

Well I just ordered 100 of them for 8$ I hope I got the right size

www.fastenal.com/web/products.ex?N=999600056&Nty=0

The ones I used were left over from a project I did for GE.   I believe they were a #10 grade 8 and about .250" long.

Question Dale,did you have to do any tapping of the holes for these fasteners?Thanks.

Quoted: Question Dale,did you have to do any tapping of the holes for these fasteners?Thanks.

No tapping.  Just drill and install.  Couldn't be easier.

my local fastenal has a couple hundred of the #10x1/4" drives in stock.  he's holding 'em for me till i get off work.  we'll see just how nice these work; i've got a SA-85 that's just begging to be built.  

tag tag tag  

This is a great thread, and it looks like a great idea.  Thanks Dale....

thanks and tagged for my 2 kits.

anyone have any idea of the rivet sizes AK's require???  I can't find a tutorial anywhere, and since I don't have a rivet set yet I can't measure them.....can anyone help??

Tag

Tag.

has anybody else tried this way of building an ak

I just ordered some from my local Fastenal. I should have them by tues. I am going to use them on a Yugo build first. here's what I was thinking... I will probably only use these in the spots in the front trunnion that I can't get at without pulling the barrel. the two lower ones in the rear of the trunnion I can use rivits.  as I will also do for the trigger guard and rear trunnion. so I will only use 2 U drive screws, just so I won't have to pull the barrel. so I don't see any problems using these. I'll post pics as I go.

Yeah, I plan on ordering a couple to do an AMD kit that is being stubborn on me; the barrel does not seem to wanna come out, even when I use my 12 ton press.  I plan on doing the 4 front trunion holes since the rest of the revits have been drilled out and removed.

Will these u-drives work if the rivets have been completely removed?  Say, by using a slightly larger size?

Quoted: Will these u-drives work if the rivets have been completely removed?  Say, by using a slightly larger size?

I would think they would work just fine if you get the right size.  The ones I used were grade 8 so they should bite into the trunnion and tang just fine.

Quoted: Well I just ordered 100 of them for 8$ I hope I got the right size www.fastenal.com/web/products.ex?N=999600056&Nty=0

When you get these, could you post a pic and tell us if they are the right size please?

Quoted: Quoted: Well I just ordered 100 of them for 8$ I hope I got the right size www.fastenal.com/web/products.ex?N=999600056&Nty=0 When you get these, could you post a pic and tell us if they are the right size please?

Well the 1st order I got was wrong  dont get #8 1/4 they are to small the next order I will get monday and they are # 10 3/8 I think those will work I will let you know monday

Quoted: Quoted: Well I just ordered 100 of them for 8$ I hope I got the right size www.fastenal.com/web/products.ex?N=999600056&Nty=0 When you get these, could you post a pic and tell us if they are the right size please?

+1
Dalesimpson,I think I may build a shrine to you in my backyard for this thread

I just ordered #10s too.  I have one that stripped the threads on and had to go up to a 1/4 X24.  It works fine, but I would like to do this U drive on it too.  What do you guys think I should go with, #12s maybe?  

TAG withTAG sauce on a bed of TAG

Taggage......

I am SO going to try this on that Ammunition Store cheapy Yugo I have coming.

And here next weekend is three days long.  Cool.

Tag, and you are a GOD for posting this.

Some brave soul should make up sets of these and sell them via PayPal for $5 each. Maybe a +1 set for slightly larger holes.

tagged too