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Lobos Checklist in progress

3548 Views 13 Replies 6 Participants Last post by  loboslanding
Ok, so yesterday I decided to go forth and begin.

I am following Lobo's checklist with this build, and am very pleased so far. Today the project should take a huge leap forward....

thought I'd try to post some pics for you all to comment and advise on.

It was pretty easy to mount the cart stop to the ORF sideplate. The hole was drilled in the exact location. I am not using a rivit gun or rivit tool yet, but rather my 6 ton bench press to crush the rivits. This is working out very very well. The rivits crush easily and completely fill in all the space of the chamfered holes. You can see in picture one that the rivit mashed fully seated into the chamfer with no additional grinding from me. The outside rivit required a little bit of touchup, but nothing major. It will will finish out nicely.

The trunnion pintle spacer gave me a small amount of problem, simply because the hole in the RSP was not quite large enough for the pintle bolt, nor was it centered exactly. I'm not sure this is a problem with the RSP, or merely some inconsistencies with each gun. I noticed that the pintle spacer on the LSP fit the pintle bolt kind of loose, but the trunnion itself is a tight fit. You can slide it by hand, but it takes a little wiggling. I mounted the RSP, fit the pintle bolt, squared everything up, then drilled the 5 o'clock hole.
I took the gun apart, mounted the spacer, and dropped the long rivit in just to align everything. I noticed that the spacer did not line up with the hole in the RSP. I drilled the 12 and 7 o'clock holes and rivited them with my press. Again, this went breathtakingly smooth, and the fit was very nice and tight. Some light grinding on the outside is all that was needed. I did have to ream out the RSP just a little to allow the pintle bolt to slide through. Also, you can see the great fit the ORF sideplate has with the trunnion by looking closely at the pintle rivit from the inside. It is really a good fit and squares up nicely.

I have put it back together in preparation for doing the eight holes for the bottom/right sideplate, and tope plate.

I do not plan to mount the safety bar. I'm not sure why this was even added as a spent cartridge will hold the bolt open for inspection on the range. I spent 30 years in the Army, and never saw one of these on a .50 or .30.

If I'm boring everyone to death with this let me know, otherwise I'll post more as the project continues.
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I for one really enjoy these type of posts. I'm just getting started on my first build and every bit of information helps. Please keep posting your progress updates.

Looks like you have it under control. Every gun is different and they all have something a little off that requires a tad of finessing with a file or a drill bit.

Glad it's going smoothly. Post mo' pics.

I was wondering if you could make the pictures a little bigger. I'm getting ready to do what you're doinga and I'd like to be able to see all the details. Thanks
I would love to make these bigger, I have detailed high defintion photos but don't know how to get past the 39 kb barrier to post em.

I'm hoping these are better. I will try to get some more posted today. These would probably go well with Lobo's checklist.

Lobo, if you want the high def photos I'll be more than happy to send them to you and maybe a detailed work outline can be fashioned.
Every onward and upward with the checklist

I pressed ahead today and made tremendous headway. First, I fit everything again and made sure that all the parts were squared up. I put in the Pintle bolt, the upper cover screw and the long lower rivit for the trunnion spacers just to line it all up.

The upper cover moves up and down without binding, that the rear plate and buffer can be slid up and out without binding, and that the latch slide moves freely and locks up as it should.

Then I mounted the whole works into my drill press and drilled the eight lower rivits using my cobalt drill and the lower plate as a guide, and the upper cover rivit holes using the upper plate as a guide.

I was fortunate in that this gun had the left side plate still attached.

I then disassembled the gun, and chamfered the holes. Here is where it may be worth the extra money to buy a carbide, or cobalt chamfer.

I used HHS 1/2 inch 82 degree countersink to chamfer. The size was perfect, but the high speed steel was not up to the task. I had to sharpen the bit after every two holes. and by the time I finished the two light chamfers for the top cover, the bit was completely shot.

Not to waste anything, I turned down the countersink, welded it to a small piece of steel tubing, then cut a bolt and welded the threads inside the steel tube. This made for a nice adjustable bucking tool that I used. Since the countersinks were nice and deep and below the level the steel, I wanted a bucking tool that I could use to seat the rivits deep. This works perfect. By turning the body of the device, you can seat the rivit below the level of the RSP. I did this with each rivit, and pressed them home in my 6 ton press. It went smooth as silk. A little slow since each rivit had to be adjusted with the tool, but the end result was worth it.

The two top rear rivits were a piece of cake. I had to ground one side flat to press up against the top of the plate, then I used my AK 47 bolt cutter/rivit tool to squeeze them home. If you are not familiar with this, it is simply a Harbor Freight pair of $9.00 24 inch bolt cutters with the jaws ground to squeeze rivits. Works great.

The front rivit I simply squeezed home with my press. Voila....the hard part is done. Some light filing on the inside to get some burrs and a few high spots......round out the outer rivits a little; and the job is done.

I again checked the fit of the cover, bolted in the lower bolt stop, and removed the pistol grip just to make sure it was all aligned. I rechecked everything with a square and it is all perfect far as I can tell.

Next installment coming soon.
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Its really nice to see work in progress photos. I see that the RRCG isnt perfectly flush up against the RSP a little gap exists, it has me worried about mine, I think I goofed, I'll post a pic when Im done at work. What method did you use to seat the RRCG? When I was pounding on mine the rivetkept backing out of the guide, its sloppy now, I think I'm sol :( .
Not sure exactly what you mean by a gap. My cartridge guide is rivited up really tight and firm. In fact, it pressed in so tight that the rivit is flush on the outside as you can see in the pictures. I hope the second posting of the pics is big enough to see.

What I did was place the inside of the cartridge stop onto a steel block in my six ton press. Then I simply aligned the press on the outside rivit and pressed it home. The metal flattened and filled the countersinks on the inside and outside perfectly. So perfect, I was almost amazed.

The $50.00 I spent at Harbor Freight for a bench top press was one of the best purchases I ever made.

I discovered, however, that the six ton is not large enough to completely drive the big trunnion rivits home. I was able to start them pretty good and get them seated, but had to finish by pounding with my 2 1/2 lb hammer.

More on that to come soon.
Comm, you're doing an excellent job. A lot of folks contributed to the tutorials and checklists in order to save guys a lot of disappointment and it's great to see you being so methodical and demonstrating excellent QC by double checking everything before you commit to each step. You should end up with a really good shooter. Good luck and have fun.

I think what he is talking about is not the plate to rear bullet guide contact through the rivet, but the tiny gap that is in between the piece that wraps around and out the ejection slot.

I have this too its about a 32nd of an inch and looking at the part before I installed it there was no metal wear on it so it more than likely had this gap to begin with. I used the rear cartridge stop just as it said in the tutorial as a guide it just moved a little during riveting shouldn't be a big deal.
I believe I understand the concern. I have included a closeup picture of the RRCG. The test for fit is actually how it contacts the trunnion. When the trunnion is in place, the RRCG should just barely touch touch it along the bottom. That is the test. That little gap along the RSP is not important. Where it meets the trunnion is important.

It seems to me that if your guide is too high, or too low, you should be able to ream the mounting hole slightly in either direction to correct it. If the hole needs to be made too oval for the rivit to fill in the space, then you may need to fill it with some weld and then refile to size. This is not a crucial load bearing part, and a repair in this manner will be totally unnoticeable after grinding and finishing, and will not affect function or strength at all.

I have included a picture of my finished side plate. It all appears to fit and function well. I do not really have any pictures of putting in the big rivits other than to say this was kind of a pain. I would suggest that you use a fairly large drill press to drill these holes. Or, like me be prepared to drill a series of ever increasingly large holes. My bench top drill press has served me well for a number of years, but was not quite up to the task of drilling it in one motion. I got it started with the correct drill, then used that as a center to drill ever increasingly larger holes until complete. This went well, but took a little time.

Also, the rivits from ORF were HUGE. The head was WAY to big. I discovered that on the first one. I countersunk the RSP and actually opened up the LSP holes a bit as well. I began the rivits with my press....but finished them with a 2 1/2 pound hammer. I still had a ton of metal to grind off. It was slow go and arduous. For the second rivit, I ground the head down before mounting it, left it slightly over size, then started in my 6 ton press. This one went way easier. The big rivits were not particularly hard, but it was the hardest part for me.

I also discovered that the remnant of the original right side plate will make a nice booster remover tool. I'm going to use a piece of pipe slightly larger than the booster and cut two slots and then weld a piece of that original sideplate in it. Voila, a booster tool. I like the idea that I'm using parts from the original gun to do it.

Next installments are the internals.
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Yep I concur on that gap issue I think Chad is just having problems getting his to tighten up... Those ORF trunny rivets are a bear... Should have mine together for a weekend shoot.
If he rrcs is a tad high or tad forward it will make no difference...the round just bumps up against it so the only critical dimension is what sticks inside and that's pretty much full proof. The only problem with a rrcs is that an '06 one sticks too far forward and the 308 links will hang up on it because they are located more rearward on the shorter 308 round. As long as you have it snugged reasonably rearward it will work just fine.
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