CoAx Press Question

[savageshooter86]

I was looking at my press last night to troubleshoot some R/O issues I was having and noticed my jaws were not contacting the rim of case the same? The left side appears to be contacting more into the extractor groove, where the right side appears to be barely over the rim.

I took the jaws apart and cleaned the "factory gunk" and re oiled the moving parts of the assembly.

Also noticed, and thought it was normal until now, the jaws seem to not open up the same after raising the ram. By this I mean I adjust the jaws to grip the case how I would like, then after sizing the jaws seem to be closed and will not allow the case to come out easily. I have to toggle the case from the jaws.

Anyone here experience the same trouble or have suggestions before I call Forster

 

[Steve Blair]

What case head size is causing the problem?

 

[savageshooter86]

this is Lapua 308 win brass

 

[Steve Blair]

I have a little trouble with magnum case heads but not with standard (.308) case heads. Do you adjust the conical plunger to provide full jaw opening? I had to do that with magnum heads. Even after that adjustment, they still must be rocked slightly to remove. I also chucked the plunger in a lathe (drill press or electric drill would work) and polished the conical surface with 360 grit paper and a little oil. Made the "feel" smoother.

 

[Steve Blair]

Here's what my jaws look like when the stage is fully lowered. Note that the conical plunger's cylindrical section is slightly above the base, just enough to fully open the jaws.

 

[savageshooter86]

stage is fully lowered

This before you insert brass(ram lowered)?

Anything else I should look at on the press?

 

[Steve Blair]

Yes, it is at this point that a case is inserted. I always turn the jaws so that the springs are at the rear. This is on the premise that the conical plunger should directly oppose the springs instead of on the opposite side. Mine have a thin coat of white lithium grease on the jaws, both top and bottom surfaces.

 

[savageshooter86]

thanks. I adjusted mine with the plunger just barely above the base plate. And will try to switch it around so the springs are on the backside with the plunger

 

[rg1]

My jaws worked a lot smoother after I used a fine flat stone on all the parts especially the blue steel spacer. The holes in mine being punched had slight swelling around the punched holes. Works perfectly now. Helps to clean the entire unit once in a while. I too use the springs in the rear. Stone all parts for a smoother operation just to remove any burrs or high spot.

 

[savageshooter86]

the blue steel spacer

you referring to the piece that the jaws sit on top of or the piece above the jaws where the 2 hex bolts are?

Did either of you touch the bottom of the jaw opening,where it sits on the rim to hold the case?

I wipe my ram arms and moving/sliding parts down after each use. Use EEzox or WD40 to do so

 

[NWnewguy]

I don't know about the second, but I know that Eezox is the best thing I have found for rust prevention, and does a good job of cleaning and conditioning as well. It's a little bit of a pain to get, and don't try to store it in a plastic container. Don't ask me how I know that one. Sorry I guess this has nothing to do with a Co-ax press.

 

[savageshooter86]

Donovan I see what you mean. I guess it wasn't lubing, but I thought it would prevent rust. That it would but wouldn't provide lubrication

Thanks for the heads up

 

[lrgoodger]

The conical plunger in my Coax turns very easily, so after running the press up and down a few times, vibration causes it to go out of adjustment. It seems to me there should be a lock ring or set screw on it to keep it in place once properly adjusted.

 

[Steve Blair]

The conical plunger in my Coax turns very easily, so after running the press up and down a few times, vibration causes it to go out of adjustment. It seems to me there should be a lock ring or set screw on it to keep it in place once properly adjusted.

[br]
I tried a lock ring (5/16-24 UNF), but it canted the plunger a little and caused binding. So, I used one of the O-rings that Sinclair supplies with their solvent port bore guides. It's a little tricky to set up. You have to position it close to the correct adjustment such that it exerts a little tension on the plunger. It doesn't take much to keep it from rotating. Any O-ring that is a tight fit on 5/16" will work. [br]
If the surface of the casting around the plunger's tapped hole was machined square, I think the lock ring would have worked.


*** corrected thread pitch ***

 

[Steve Blair]

Well, my previous post got me thinking about how the O-ring solution came about several years ago. I had originally thought the thread was 5/16-32 UNEF (and bought a tap) but it turned out to be 5/16-24 UNF. The reason I used a lock ring instead of a nut was not the thread but the nut height. The stage was bottoming on the nut. Even with the slim lock ring, the casting surface was too uneven to allow the ring to be tightened. [br]
Yesterday, I looked over the press and realized that the entire bottom was machined and appeared to be pretty square. Since it is the seating surface for mounting, it may be the first registration surface machined on the casting, meaning that all subsequent features are machined referencing it. When the conical plunger is adjusted to the correct position, a small amount of thread protrudes from the bottom. I still had a 5/16-24 nut from the original attempt. Tightened on the protruding thread, against the bottom surface, it does not deflect the plunger. My plunger is now immobile, will not unscrew and the stage can still travel to full bottom position. [br]
The moral of this story, as most men already know, is never throw anything out because you will inevitably need it again, later.

 

[lrgoodger]

That's what I was thinking to try. Just had not gotten around to it yet. Thanks.

 

[artbosco]

I was looking at my press last night to troubleshoot some R/O issues I was having and noticed my jaws were not contacting the rim of case the same? The left side appears to be contacting more into the extractor groove, where the right side appears to be barely over the rim.

I took the jaws apart and cleaned the "factory gunk" and re oiled the moving parts of the assembly.

Also noticed, and thought it was normal until now, the jaws seem to not open up the same after raising the ram. By this I mean I adjust the jaws to grip the case how I would like, then after sizing the jaws seem to be closed and will not allow the case to come out easily. I have to toggle the case from the jaws.

Anyone here experience the same trouble or have suggestions before I call Forster.

Call Forster. Always go to the designer and manufacturer first. Saves lots of conjecture and guessing.

 

[Steve Blair]

Call Forster. Always go to the designer and manufacturer first. Saves lots of conjecture and guessing.

[br]
Forster bought the design. Bonanza designed the press. Regardless; Does Forster have a monopoly on ideas? Do you realize how many improvements and inventions have resulted because a manufacturer was unwilling to address a specific need? Not to say that Forster is unwilling to help, I've actually found the opposite. But, these are pretty simple machines and are well within the ken of ordinary people.

 

[savageshooter86]

I would rather find solutions/suggestions from other shooters who have used the stuff and tinkered with it to make it work better. Most companies oppose you (the user) to making changes. But in reality the mechanically gifted shooters here have many tweaks that make stuff better.

All the info here is helpful.

 

[waltk]

The spring loaded jaws are alright but I ended up using a standard shell holder which I prefer.