Author Topic: Need help with Thumlers tumbler (Read 1161 times)

cooper · « **on:** November 08, 2005, 09:01:37 AM »

Ive been having a lot of trouble with case stretching in my 40/70 Straight, so decided to go ahead with the ceramic case tumbling cleaning method. I bought a new Thumlers Model B tumbler (the heavy duty model), and some ceramic media. The media works fine, but I may be having problems with the tumbler.

When I tumble, I use 8 lb media, 3 cups water, and 50-100 cases, for a total weight of about 12 pounds. While running, the tumbler barrel (not the motor) will hesitate for a very short time (like one-half second) and then go through some jerky motions to catch back up. It does this constantly if you watch it for 1 minute, it might do this 2 or 3 times.

I have only tumbled 3 times, for a total of 8 hours. Im starting to get some black rubber buildup (from the rubber coated rods where the barrel rests) all along the edge of the barrel, and also some small black shreds of rubber are coming off and falling onto the base.

Is any of this normal?

ShortStake · « **Reply #1 on:** November 08, 2005, 01:37:03 PM »

Cooper,

Your Thumbler tumbler problem is a frequent problem.

Locate the white plastic barrels on the two metal cross shafts.

Remove the cross shafts from the tumbler frame and then remove the keeper washers from the ends of the cross shafts.

Remove the white plastic barrels and use your neck chamfering tool to put an angled cut on each end of the barrels. As they come from the factory the white plastic barrels are somewhat of an interferance fit.

Clean the white platic barrels internally and reinstall onto the shafts. That should cure the "jerky" movement problem. Antoher ongoing problem is the white plastic barrels seem to gather crud from the spinning shafts. My answer to this problem is to spray the shafts/white plastic barrels with a lubricant prior to each use.....

Works for me.

Coldspring · « **Reply #2 on:** November 09, 2005, 02:00:33 AM »

Cooper:

It does not make sense but I have found that I get better results with 2 1/2 to 3 pounds of media and about 2 cups of water than I did with 8 pounds and 3 cups of water. Keeping the bushings on the shafts oiled as it says in the instructions is necessary.

Wayne

cooper · « **Reply #3 on:** November 09, 2005, 08:08:53 AM »

Thanks for the info, guys. I'll be shooting and tumbling cases this weekend so I'll give those tips a try.

arnie19 · « **Reply #4 on:** November 09, 2005, 01:01:04 PM »

The cases are probably stretching because your head space is not right .Tell me what rifle and what brass you are using . Arnie

cooper · « **Reply #5 on:** November 10, 2005, 05:57:14 AM »

Shiloh Sharps 40/70 Straight with Buffalo Arms .068" reformed 30/40 Krag brass.

Headspace on a rimmed cartridge is measured from the face of the breechblock, to the front of the rim.

This rifle has a very short throat. With one bullet in particular (the Lyman Snover) I have to seat it very deep (.9", as I recall) and in addition when sized .410 it is a tight fit. The fit is actually too tight - if I decide to use this bullet in the future, I will get a larger expander die.

When the cases got dirty (after being fired about 5 times), loads with this bullet stretched the case mouths a full 0.1" (one-tenth of an inch!!!). They went from a normal 2.5", to 2.6" or a bit more. The case mouths stretched into the "leade", and the throat, and even the start of the rifling was visible right at the end of the case mouth!

I'm almost certain that the corroded interior of the cases, exacerbated by the deep seating depth, and the tightness of the bullet fit, caused the bullet to "grab" the case mouth, and pull it along with it when it was fired.

I don't believe this is a headspace problem.

ShortStake · « **Reply #6 on:** November 10, 2005, 07:42:12 AM »

Cooper,

Your stated case stretching scenario could well be caused from excessive buildup of powder/lube residue in the cartridge case interior walls.

You might try using a brass/bronze brush of slightly larger diameter than the cartridge case mouth as a method of removing the black powder residue.

My method in the past was to utilize an electric drill with the wire brush in the Jacobs chuck to remove any interior residue. The use of ceramic media/tumbler for case cleaning has eliminated this step.

Clarence · « **Reply #7 on:** November 24, 2005, 11:23:54 AM »

Cooper,

With the Thumler's Tumbler, I use around 2# of ceramic media for 70-100 cases. I use a capful of the burnishing compound, and probably no more than a couple tablespoons of water (really, just what's left after the final rinse).

As someone pointed out, keep a drop of oil on each of the bearings. I find I seldom need to add oil.

I have no hesitancy or jerking motion, and the cases are beautifully clean in 3-4 hours. No need to use a brass brush on the necks; we all went to ceramic to eliminate that tedious job.

Clarence

cooper · « **Reply #8 on:** November 30, 2005, 04:31:16 AM »

Just to let you all know - I did take apart the white plastic rollers, reamed-out their ends a little bit, and then oiled them inside with RemOil.

Worked perfectly! No hesitation or jerky movements at all.

Now I put a drop of RemOil on each one each time I tumble. Don't know if I need to oil it that frequently, but it sure works.

Thanks for the info.