HELP! Lyman Power Trimmer butchers cases!

[30cal_Fun]

My Lyman universal power trimmer (case trimmer) makes strange noises and completely butchers the cases. The case mouth is left with four distinctive diagonal-castle-shaped bumps.
This problem persist through different brands of cases (S&B, Magtech, Fiochi) and different types of cases (.44 sp/mag and 7.62x54r).
The bumping sound worsens over time and about halfway into the trimming process I am unable to continue because the cutter head seems to bounce off the case mouth.
It primarily happens when I am trimming .44 magnum cases to special length.
One distinct feature of the problem is that the more the case needs to be trimmed the worse the problem gets. A once fired and sized .44 special case that only needs to be cleaned up in the trimmer hardly has the problem. It just leaves very small dents in the case mouth.
It doesn't matter if I apply light, moderate or hard pressure on the the handle.

Does anyone know what is causing this?!?

It seems as if the motor doesn't have enough power to cut cleanly and/or that the cutter head is dull. The cutter head is a normal one, not the carbide.
The cutter is in great shape though and very sharp and the motor doesn't seem to skip or be obstructed in any way.
I bought this case trimmer second hand from someone who bought it but hardly used it because he build his own case trimming station.

I made a short video of the cutter butchering a case. You can clearly hear that the bumping sound worsens through the trimming.
http://www.youtube.com/watch?v=bbzQS...ature=youtu.be

And some pictures of a typical case. The first two pictures are of the case from the video that was a .44 magnum. The third picture is a typical .44 special case after just been cleaned up in the trimmer. This one was also trimmed from magnum to special length before firing and of the same brand. As you can see it just has two small dents.

[precision_shooter]

Cutter head clogging up?
Brass getting hot from friction causing the cutter head to skip?

[full case load]

In the video I couldn't see anything that appeared "loose" at the cutter end or the case end, but it did sound like it was "chattering". Maybe re-check for any looseness at each side. ? including rotational bearing(s) put under the same pressure you are putting on it from the case mouth. (just trying to throw something out that maybe you hadn't thought of, good luck)

[30cal_Fun]

Thanks for the ideas.

The cutter isn't clogging up. the shavings fall to the side. I even cleaned the cleaner every couple turns and it made no difference.

The brass getting hot doesn't seem likely either since the problem is present from the start on cases that only need to be trimmed lightly.

The holder has a little play side to side. The play is between the hole in which the holder rod rides and the rod itself. Other than that everything is rock solid.
But it can't be adjusted or opened up in any way and it is in good shape. Nothing seems out of the ordinary.

I send an email to Lyman, I'll post the reply as soon as I get it.

[Bailey Boat]

Cutter is out of spec.....

[rg1]

The pilot is running out and also possibly too small in diameter for the case necks. At start up in your video you can see the pilot not running true. Also the cheap fiber bushing used in the chuck shaft isn't precision like a hardened steel bearing that should have been used. I would guess it has a fiber bushing like the Universal hand trimmer and allowing movement of the chuck? Could be the hole in the cutter head is too large for the shaft on the pilot and the set screw is pushing the pilot off center?

[30cal_Fun]

What do you mean with the cutter being out of spec Bailey Boat?

rg1: I posted my reply to your post on the High Road. The cases fit snugly over the pilot but the pilot is off center.
It has the plastic bushing and aluminium sleeve, there is play between the plastic sleeve and the holder rod.
Other pilots are more or less centered well, the 22 pilot is even worse off centered though while the 30cal pilot is perfectly centered.
It does seem that the pilot is being pushed off center.

Still, I think most of the wobble comes from the holder assembly because even with the perfectly centered 30 cal pilot my 7.62x54r cases have the same problem.

[F. Guffey]

Around here there is no shortage of things that cut and trim, the universal case holder has too much slack. the problem could be caused by an eccentric condition with the cutter/pilot or shaft. I do not have the power tool, I have the hand crank powered model, I also have trim dies that are used with a hack saw and file. I also have the L.E. Wilson case trimmer and RCBS collet case holder, none of my case trimmers wobble like your Lyman, I would suggest you set-up a dial indicator to determine where the eccentric movement is coming from.

It could be the case, meaning if the case was straight and aligned in the universal holder the case would not cause all the wobble.

Try to install the case, then insert the pilot into the case then secure the case on to the holder, meaning? The case could be too held tight to allow for alignment.

F. Guffey

[30cal_Fun]

I don't think the case is held to tightly by the pilot. It fits snugly but is easily slid on and off, there is no binding whatsoever.

I don't have a dial indicator.
The wobble originates from the play between the holder rod and the plastic sleeve in which it rides. I have no way of tightening it up though.
I'll wait for the reply from Lyman.

Or should I just sell this one and buy a different case trimmer? Any suggestions?

[Chaz88]

I don't have a dial indicator.

If you have a set of vernier calipers you can set them up in a vice to cheat a crude dial indicator and see what the largest run out measurement is. It takes very little run out to chatter and break carbide lathe tool bits. I think too much with a case trimmer would cause the problems you are talking about.

[30cal_Fun]

That might work.
But I can tell your right now that most of the wobbling is at the end of the case holder. You can see in the video that the holder part is wobbling very much.

[full case load]

I didn't notice that movement the first time I watch the video, but by placing the cursor on the case/chuck side movement is obvious. Cutter side stays true. In my opinion that amount of movement allows the bump/chatter. Sometimes I overlook the obvious, but I would think that alignment should stay true. Lyman would be getting it back if it was mine.

[Hawg]

It looks to me like you're pushing too hard against a dull cutter.

[F. Guffey]

http://www.lymanproducts.com/lyman/c.../LyC_CT_PT.pdf

“Any suggestions?” Because of the distance and the cost trading is not possible. I have L.E. Wilson case trimmers from the mid 50s, I have the Lyman universal chuck/manual hand crank model, I have the Hornady case trimmer that uses shell holders, I have the RCBS collet trimmer. And, I have trim dies (my favorite), I have a box of Lee parts and pieces that can be made up to trim just about anything. Then foreign to reloading I have aircraft counter sinks, to appreciate them a form/trim die is necessary.

“Any suggestions?” I said there is no shortage of things that cut and trim around here, When reducing wobble/chatter I want the shortest hook up I can get. All of my case trimmers are locked down on the case head end, the adjustable end on my trimmers the cutter end.

Just curious, it would appear you are removing a lot of brass, when you remove the case I only see evidence you have one cutter of the four that is cutting. When using a cutter with one cutting surface the feed must be slowed down, I have used broaches for surfacing, there is an advantage with a broach, the height of the cutters are adjustable.

F. Guffey

[HiBC]

You said you got it second hand from someone who made his own setup.

You also said the cutter is sharp.

Could it bee the original owner "sharpened" the cutter?

I think all the wobble is coming from having only one flute of the cutter engaging,and its dull.

I suspect a new cutter head will fix you up.

You also might check how the cutter is seated to the drive spindle.If its cocked off somehow...sitting on a chip or?the cutter head itself may be wobbling,causing one cutting edge to be high.

Also..If your pilot fits close,and if the pilot is stable in the cutter head,the tool should work with only one cutting edge.The RCBS cutter head I have uses one cutting edge to trim and another to chamfer.

There are subtle features in the cutting edge grind for an ideal cutter for this,not sure Lyman uses them,Positive rake on the leading face of the cutting edge encourages a cutter to suck into brass.You want zero or negative rake.The clearance angle behind the cutter is important on an uncontrolled feed such as your machine has.Too much clearance angle will feed aggressively.Dull plus too much clearance will not cut till you apply enough force to overcome and make the dull cutter bite,then it will dig in.

IMO,the cutter is not running co-axial with the spindle and/ or the cutter geometry has been altered by your DIY guy.

I see no need for a new machine.

[30cal_Fun]

I finally got an answer from Lyman.

Their explanation was that trimmers are not designed to remove that much material and that any trimmer would do that (my el cheapo Lee trimmer works fine however). They also said that a dull cutter could very well contribute to the chattering of the cutter.

They offered to send me a new cutter head.

I'll let you know when I have news.

[Brian Pfleuger]

Well that's just silly. The cutter is designed to cut cartridge brass. How does it have any idea if it's cut 0.001 from a case or 0.100? Brass is brass, except as you cut down into lesser annealed portions which isn't that dramatic of a difference anyway and probably not going to happen in that roughly 0.1+ trim.

[Chaz88]

Well that's just silly. The cutter is designed to cut cartridge brass. How does it have any idea if it's cut 0.001 from a case or 0.100? Brass is brass

I agree. I think they are just making stuff up. With the correct cutter speed and feed rate it should have no problem cutting for whatever the maximum feed depth is.

But sending a new sharp cutter might actually help.

[F. Guffey]

http://www.midwayusa.com/product/274...de-cutter-head

I do not know what cutter they will send you, no matter, if it is the expensive of the economy model, U believe you should install the case align it then secure the case to the automatic case holder.

F. Guffey