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Been Busy......

Haven't posted much lately, especially here in the Gunsmithing Forum. Since I became General Manager I haven't been on the lathe at work. I spend all my time coordinating things, dealing with employees, putting out fires, talking to customers. You know, GM stuff.....

I did get my checkride finished for Civil Air Patrol, and I learned my LRBR heavy gun now likes to be cleaned hard.......and it's hard to argue with the 1000 yd 10-shot groups of 5.7, 3.9, 4.2, and 5.0 that it rewarded me with a couple matches ago.

I have done some machining work at home. A buddy called in a favor and made me chamber a dinky Sako A2 in 25 Creedwin. It was a super skinny Pac-Nor barrel. It dialed-in nice and I got the best looking button rifled throat I have seen. However, I had to finish threading the muzzle with a thread file. The muzzle end was so bendy that it would push away and not cut when I got close to being done, and this is with high quality threading inserts and proper tool height.

The Sako A2 was a hassle with the protruding extractor, and it took me a bit to figure it out. It was also 95 degrees in the garage. The Astro-Swiss flows REALLY well from my 1/4 HP immersion pump at 95 degrees.

The bendy muzzle got me to thinking about a better way to hold a barrel than my inboard spider. I took one of those Grizzly gunsmith spiders and fit it to a thick D1-4 back plate. The spiders four screws are 1/2" in from the face of the spider, so there is always an extra half inch of unsupported barrel vs a chuck. Most of the time that's no big deal, but it got me to thinking.

So I bought a Precision Matthews 6″ Adjustable Ultra Precision 3 Jaw Chuck, D1-4 Mount. It cost $699.

It's a very nice chuck, probably 95%+ of the Bison Set Tru we have at work. The biggest difference is the grub screw on the PM push where they pull on the Bison--at least I think they pull on the Bison. I don't use that lathe so I could be wrong.

I put a barrel stub in the PM after I had it mounted. After 2.5 hours I still couldn't get it dialed in. I would get it to about .0003, make one last tweak and then lose the whole thing. It was also 90+ degrees in the garage, so I walked away wondering if I had wasted my money.

I called PM the next day, and concluded I just needed to "pay my dues" with learning the set-tru design.

About three weeks later (yesterday), I got to mess with it again. I needed to throat my "New" (FN) Winchester M-70 in 33-28 Nosler a little longer, and then Plus P the throat. So I had to dial in the barrel based off my existing chamber. It went fine with the PM Chuck and I got it where it needed to be. The longer throat looks awesome as does the Plus P. Then again I do have my PM 1340 GT very well aligned. I am sure it also helped that I now have a mini-split in my garage that keeps the third bay comfortable.

I also decided to open the action for a Wyatt's extended magazine box. That was a pain, but I got it all done, have 3.825" of mag length, and it feeds and ejects like a CRF Model 70 should.

I do need to learn how to use my Mill better. It is a PM 833T. I installed power feeds and a DRO. It only goes to 1500 RPM, and I didn't get a great finish as I machined on the action. I guess I need to take the time to figure out what end mills to get, similar to what I did for my lathe tooling. I was able to polish everything up with my new Dremel and a cartridge roll. My old Dremel just up and died, but it was probably 20 years old.

While I did get everything machined okay, I was having a hard time getting the rifle to feed. I stumbled across a couple Youtubes by Kevin Wyatt, and learned something.

At work we can often fix a feeding issue--which is almost always the follower heel dropping, by increasing spring pressure. Kevin said that when we lengthen the action for a longer mag box, the follower spring needs to move rearward on the floor plate. He said to strake it in place. I wasn't able to do that, but I did use double stick tape to hold the spring on the floor plate. I guess I'll expoxy it in place as the tape won't hold forever. But it was amazing how it went from me thinking I had ruined the feeding to having it work nearly perfect just by moving the magazine spring back. Time for load dev.

That's it for me. I don't know when I'll be able to stick my head back up.....
 
How end mill and reamer profiles contribute to the final product is very interesting. The material itself can be the biggest variable and whenever possible, I like to work that out on some excess material before "...gettin' to the rat killin" as The Duke would say. :)
 
Before you go down too much of a rabbit hole on the mill...

1. Don't waste money on steel tools.
2. Thoroughly check the fitment of the gibs... Long threads about this for the 833 on the machinist forums...
 
Before you go down too much of a rabbit hole on the mill...

1. Don't waste money on steel tools.
2. Thoroughly check the fitment of the gibs... Long threads about this for the 833 on the machinist forums...

So I looked at HM and saw your thread on the gibs. I got mine in 2018 and noticed the .001 to .002" table rise as well when I first got it. After the movers tipped it over and I replaced the X-Axis screw I went through everything (made it better then new) and my table is still like yours. About perfect for the 12 or 16" in the middle of the travel but lifts .001 to .002" at the ends.

My big concern is how limiting is 1500 RPM. I do mainly stocks and a little machining. It does okay, but I am wondering if 1500 rpm is really enough for a 1/4" carbide end mill when cutting stainless.

I am wondering if I should sell it and get an 833TV or a knee mill.
 
So the guy I have on the mill (Bridgeport clone) most of the time at the shop says 1000-1500 is the rpm he uses when machining actions. The guys next door have three CNC Mills and a CNC lathe, and just they gave me some lightly used high quality endmills. There goes my reason for a new Milling machine......
 
I'm still a little intimidated by the mill, so I've never run it must faster than 12-1300rpm, and it's fine with stainless. Gotta keep the mist coolant going. That's more important than the speed in my experience.

I wouldn't go through the effort to trade it for a TV. If you have the space, get a Knee mill. Lots of options out there. I'm space/height limited so the 833 was one of my only choices. It's more than enough to do stocks and the light work we run into as 'smiths
 
Higher speeds are usually for aluminum and CNC. Carbide end mill at 1500 will cut the stink off of a dog turd.
 

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