Shooters Forum banner

1 - 20 of 47 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter #1
I have an RCBS Rotary Case Trimmer -2 . When trimming 8mm Mauser cases, after the trim, it's very difficult to pull the pilot out of the case. Very difficult, like I need to use a prying tool to get the cutter shaft out of the case. Any idea why so difficult. Smaller calibers are not nearly as bad.
 

·
Registered
Joined
·
4,736 Posts
Are you talking about the powered case trimmer or manual?

Using a steel cutter head or carbide?

Might check the cutter head if your trimmed cases show a lot of burrs at the case mouth, a sign that the cutter head needs resharpenning or replacing. Your smaller cases are being trimmed at a different point on the cutter head which is still sharp
 

·
Registered
Joined
·
1,648 Posts
Cussing the case trimmer...

The burrs in the case mouth, so far as I'm concerned, is the cause of this problem.The Lyman has done this jamming up all along. My solution on the RCBS is to lube inside the case neck. For the Lyman, remove the case and champher the case mouth half way or so through the trim. My most recent dance was on grossly too long 243 brass.:mad: My solution of last resort is to get out the Wilson trimmer. Getting a new cutter head(s) sounds like a plan here on the hill.
 
  • Like
Reactions: Marshal Kane

·
Elk Whisperer (Super Moderator)
Joined
·
10,952 Posts
The pilot itself may have a slight chamfer that the case mouth burr is catching on? I pull the cutter away while it's still spinning. That's on an ancient Forster though. Not sure how the RCBS is set up.

Thinking out loud.

RJ
 

·
Premium Member
Joined
·
14,829 Posts
Make sure the pilot is jammed solid against the cutter. Any gap there causes all sorts of sticking problems. Polish the pilot by chucking in a drill and holding abrasive on it.
 

·
Registered
Joined
·
776 Posts
It is a burr formed on the inside of the case mouth, caused by the gap JBelk described.

When you pull the cutter out and notice that it was hard to extract, make another cut. The burr will have folded out and will give an erroneous length reading.

I have an RCBS Rotary Case Trimmer II I bought back in the early '90s, and it does like you've described with some pilots. I simply reinsert the cutting head and turn again, give a couple of turns, and the withdrawal is without resistance, length is more truly represented and consistent.
 

·
Premium Member
Joined
·
14,829 Posts
If there's a gap between cutter and pilot, check the length of the pilot's stem. It could be bottoming out in the hole and leaving the gap.
When I suggested spinning the pilot to polish it, please take it out of the cutter first.:eek:
 

·
Registered
Joined
·
5 Posts
Discussion Starter #9
The pilot itself may have a slight chamfer that the case mouth burr is catching on? I pull the cutter away while it's still spinning. That's on an ancient Forster though. Not sure how the RCBS is set up.

Thinking out loud.

RJ
I think you hit the problem on the head. A close exam of the pilot with a loupe shows a slight chamfer on the back edge. I have since put it in the lathe and taken a face cut on the back face of the pilot to make a truly square edge. Now there is no chamfer cavity for the burr to roll into. The cutter I am using is brand new, with the pilot seated completely into it. I have not yet tried out this solution.
While the smaller pilots may have the same chamfer, because the case is smaller, it take a lot less force to shear off the burr when retracting the cutter shaft. Bigger case, bigger circumferential burr, more force.
 

·
Registered
Joined
·
1,648 Posts
No doubt the pilot not being right is a problem. In my experience the case will pull away from away from the cutter but remain stuck of the pilot. We may be talking about two aspects of the same problem. One contributing factory may be the amount of pressure applied to the cutter. A burr may be aggravated by force on the handle. This is a situation where one can have all these things happening at the same time. For me, the sticking is worst in the Lyman. That trimmer has some but not a great deal of use. That is a good trimmer with an eccentricity with smaller diameter necks. No problem with the Wilson. Happy New Year friends. I'm off to the range.
 
  • Like
Reactions: Marshal Kane

·
Registered
Joined
·
4,736 Posts
Haven't experienced this problem with any of my RCBS pilots but agree that any kind of opening between the pilot and cutter head is a place where brass shavings can accumulate and bind the case. If recutting your pilot solves the problem then you've found the cause and eliminated it.

I'm using a carbide cutter head and I keep an old toothbrush handy which I occasionally use to brush off any brass shavings clinging to the blades. Continued cutting with brass shavings clinging to the blades only tends to make the brass adhere tighter on the blades causing rougher cuts. YMMV
 

·
Elk Whisperer (Super Moderator)
Joined
·
10,952 Posts
McGuiver, I await your test results. :D

RJ,
 

·
Registered
Joined
·
1,648 Posts
Neck thickness...

Lyman trimmer: Did my own little experiment with the 243 brass. No problem. Basically, had been trimming one brand of brass and swapped to another. What would happen if one brand were thicker than the other. Question: What role ,if any, would neck thickness play in the case this case sticking on the pilot.:( What about the diameter of the pilot?
 

·
Premium Member
Joined
·
14,829 Posts
Either the hole is too small or the pilot is too large. Which is it? If the cases have been re-sized, the expander ball should have made the hole the right size for the pilot to slip into. The thickness of the neck has nothing to do with it.
 
  • Like
Reactions: Marshal Kane

·
Registered
Joined
·
5 Posts
Discussion Starter #16
Lyman trimmer: Did my own little experiment with the 243 brass. No problem. Basically, had been trimming one brand of brass and swapped to another. What would happen if one brand were thicker than the other. Question: What role ,if any, would neck thickness play in the case this case sticking on the pilot.:( What about the diameter of the pilot?
The pilot diameter is fine, #32 for 8mm Mauser. The pilot slides into and out a case that has been chamfered inside and out, no problem. It was when the case was on the pilot and trimmed, the burr would flow into the chamfer on the back side of the pilot. Squared off the back edge of the pilot, now no problem.
 

·
Registered
Joined
·
4,736 Posts
Either the hole is too small or the pilot is too large. Which is it? If the cases have been re-sized, the expander ball should have made the hole the right size for the pilot to slip into. The thickness of the neck has nothing to do with it.
With regards to resizing, then trimming handgun cases, I've run across a problem when resizing with my Lyman dies then trimming with an RCBS trimmer. Seems my Lyman dies resize a bit smaller than RCBS dies so I have to expand the case mouths slightly to get them to fit onto the RCBS pilots. This doesn't happen when I resize with RCBS dies then use the RCBS trimmer. With rifle cases, all I use are RCBS sizer dies so in this case there isn't a problem.
 

·
Registered
Joined
·
1,648 Posts
Pilot diameter and neck thickness plus forcing the cutter

Right now I'm looking more to the size of the pilot as it relates to the thickness of the case neck. Also, pushing or forcing the cutter aggravates the problem. Actually, this may be the problem. I don't think this chamfer on the pilot adds up to much. Remember, when the expander ball pulls back through the neck some degree of neck tension is evident. Also, another consideration of spring back when the ball passes through the neck-size does count. The size of the pilot and the thickness of the neck is a variable. The pilot is fixed the case is not.
 

·
Premium Member
Joined
·
14,829 Posts
Here's one solution if you have a common bench grinder.

Just cut a reamer notch in the pilot. The vertical face of the notch is the cutting edge so cut the notch where with proper rotation the vertical face of the notch is the cutting surface.

The one on the left was cut with a mill before heat-treat.

I make a 6mm wildcat from .308 cases and the necks ripple some. The reamer notch cleans the neck as it's being turned for .0097 thickness.
 

Attachments

·
Registered
Joined
·
1,648 Posts
The Best Answers

As usual, the best answers are the simplest. :D
 
1 - 20 of 47 Posts
Top