Case trimmer

T

Tlewis81

New member
Got an old.school rcbs trimmer...the manual all by hand any others that are more accurate at trimming length? I see a deviation a little more trim or a little less trim depending on pressure i put on it not by a lot
But may 5 to 10 thousands high and low only an occasional case like that but any better trimming options
 
Trimming should be done AFTER resizing, and after gauging/measuring the case from Datum point to head stamp.

DatumPoint_zps8j7sg7xk.jpg


Once the case shoulder/Datum point is in the correct place,
Then trim for length.

Now, the quickest way to trim is with a cutter that indexed off the Datum point.
There are several brands of differing quality, but I prefer the 'Trim It II' because its adjustable for about any caliber,
Its got a bearing with insert you change for different cases,
And it cuts for length, does inside & outside tapers/deburring.
Takes less than one second with a power drill turning it.

CutterToolBit_zps0qb6i9qk.jpg


TrimIt_zpshqi6wktx.jpg


At $135 its not for the guy that cranks out 300 hunting rounds a year.
For the guy that cranks out 1,000 or more at a time, just the automatic taper/deburr time it saves is worth the money.

Each cutting bit has 3 cutting grooves, so if it dulls, you simply rotate the triangular bit to the next cutting groove...
A cutting bit is about $30.
 
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Graduations on the drum (picture above, next to red case) are about 0.002"
The threads/set screw lockdown will let you get anything you want,
Most people won't have a micrometer accurate enough to gauge precision since you can stop between graduations and lock down at any point.
I can get 4 digits behind the decimal point consistantly.

A pilot in a bench cutter will give you axial control, hand cutters won't since they don't use a pilot.
This thing gives you pretty precise control of the cut since it uses a index off the datum point with a sleeve to center the case.
And no deburring/champerfing with hand cutter when you are done with hand/pilot bench cutter, all cuts done at the same time.

I have a stright line case sizer (motor driven) and this particular cutter trims to length, indexed off the datum point, and it works with a common hand drill for someone doing smaller scale.
 
Common problem with manual crank hand trimmers. Especially when the cutter starts to get dull. Also good lubrication of the spindle and the positive stop helps a lot. Easier to crank plus the lube on the positive stop helps get a more consistent length. However even if my trimmer is doing a good job on case length uniformity I still measure the length of every trimmed case with my calipers. Some brass is harder and multi-fired brass is harder to cut. Carbide cutters now available for some manual trimmers makes cutting much easier and worth the cost if your cutter is dull. I've had some success taking a flat sharpening stone and stoning only on the face of the cutter teeth. Or just buy a replacement spindle and cutter for your old trimmer.
 
Rust/corrosion, not use, is generally harder on the cutting edge.
In the shop, I go to extremes to keep the edges from corroding between uses.
Cutting tools often come sealed against corrosion, but once you peel it off, all bets are off...
If you see corrosion, you can bet that super fine edge was the first victim!

I'm not crazy about flat face cutter tools, I load a lot of flat back bullets, so the champfer is a requirment, and that's a hand operation, time consuming, no matter how you go about it.
I'm fond of the 'V' shape cutter since it does the tapers/champfers the same time it trims for length. No second or third hand processes...

Its up to each person how they want to do things, how much time they want to invest, this is just 'Another' way to do things...
 
I am a solid advocate of the Gerard Tri Way Trimmer (I have two)

It indexes off the shoulder, never could get consistent CL with the hand trimmers.

The variation is a few thousandths.


If just a few hunting rounds the hand is fine, doing target shooting then one of the shoulder trimmers.

Little Crow is good but does not to the chamfer and de-burr, nice to get it all in one step and just have to clean the primer pockets on the prep statin.

Call Little Crow in between, cost less, does less but a nice one.
 
I've been using the RCBS Trim Pro2 trimmer for 25+ years very accurate. To be off that much I would think your adjustment knobs, one or both could be loose.
 
I've got the RCBS Trim Pro-2 and then added the Motor unit to it. Helped a lot but I did see a bit of inconsistency, depending on the pressure applied as you did. Mine used the old collet type shellholder which I didn't care for, it's lasted 28 years!

I've also used the Lee Gauge Trimmer. IMO, works great if you are doing 20 or so at a time. The last batch of 168 .223's wore me out. Went out a few days later and bought the Trim-It. Wow!!! talk about fast!, I didn't spring for the 3 way cutter yet, but I can upgrade to it at any time. They are local to me, so it isn't that big of a deal. I'm also running over to get the motor for it, so I don't have to mess with my drill anymore.

As long as your brass is resized consistently (I find using the same manufacturer and even year helps alot ie., LC13, makes a pretty big difference). The variance is pretty minimal.
 
My first trimmer was a RCBS model un known but it used collets. That wasn't a good design do to it tightened around the rim that could very in diameter. That would give variable lengths.
Then they did away with the collets and clamped the head stamp to the base. It helped a lot to get more consistency in length.

I recently purchased a Wilson trimmer although I haven't used it yet I believe it will give me more accurate trims.
 
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