635 replies to this topic

[Loci]

ever thought of using a car battery charger as a power source?

Fraser

[Stuart]

Yes although I don't bother. I just use a car battery and I can put my ball mill anywhere I like.

Stuart

[mminson]

If you're looking for a cheap motor, I would head to eBay. I got a nice little 1/25 HP motor for $4.99 (American). This link Small Motors takes you to the Less than 1 HP Motors page where you can find many small motors, whether AC or DC. Try the 1-10 HP list as well since many people list in both places.

Mince

[LuMpY]

Would the car battery charger have enough or many amps to power the motor (sorry for the possible dull question)?

Edited by LuMpY, 08 March 2004 - 07:35 PM.

[Stuart]

Yes. Electrical appliances require a set voltage, however, they will only draw as many amps as they need due to their internal resistance.

Stuart

[Jerronimo]

Jep, I decided to make my own ballmill.

As a millingjar I intend to use a length of 8''(200mm)diameter PVC pipe with a wallthickness of 4 mm, I've read that the bigger the diameter the more efficient the mill will work.
The motor will probaly be an old washing machine one(1400 RPM)
The media will be brass cilinders, they ain't cheap but will probaly last me a lifetime.
But what diameter and length of media will work best?
I realy have no idea.

[Lil_Guppy]

This is my new baby (beast):



Good for two 110mm (dia.) x 160mm (long) jars. I only have one running at the moment. Cutting 180 pieces of tube is not fun, so the next 180 pieces will have to wait. FYI, I used lead obtained from a bullet stop at the local pistol range (mmmm... free lead), and cast them into ?in long ?in diameter pieces of tube. My milling jars are PVC, and can handle ~340g batches of black powder.

[pritch]

I've just bought the evans junior from manchester minerals. Came to ?70 and has a 1.4kg capacity. 11mm lead balls from sutlers to go with it.

[sasman]

I've just finished My BallMill ,Thanks To BurlHorses earlier Post,I followed his advice and Got the 4 Rubbers rollers from the Ebay Auction. at $4.50 each .The only concern about the rollers are that they bend slightly when i put a fully charged Drum on them?...

Ball Mill in action
The bearings were $9.00 for a set .I tried getting bearings here in the UK but the cheapest i could find were ?11 each !!!.Most expensive part was the 8" Pulley Cost ?20 the 1 3/4" pulley was ?5 .The Large 2800 rpm motor is 1 hp 240v Air cooled found it knocking about my gargage..i Used Exhaust clamps to hold the bearings down Cost about ?2.50..I geared up the mill to run at 80rpm with a full load of media (30 lbs lead/antimony .690 " Diameter) .....
.....

The Big Blue Drum is fantastic i got if From the usa and its worth every penny its outside Diameter is 9 1/2" .Inside its Hexaganol shaped rubber lined about 7 1/2" across,so lift bars are not needed..The drum is sealed with wing nuts and a large rubber/steel lid totaly leak proof!... I've only just put it into service today so not made any BP with it But i reckon it should Make about 2 lb Of BP..per load...I got about 15lb of willow charcoal to mill so got a bizzy few days ahead of me ....Thanks Burlhorse for the Tips

[parabolic]

That looks VERY impresive.. Well done sasman..

cant wait till I build mine.

[Richard H]

That looks excellent Robert! While my Evans CR2 may not match the output of your beast, it still makes a really MEAN blackpowder with good willow charcoal and my brass round bar media.

Pritch, you might find that the junior tumbler is not best suited for milling chemicals. A slightly larger investment in the form of the CR2 is recommended in my opinion. Regardless, let us know how you get on.

[Dan]

I made mine out of old copier parts, wood, and pvc. it wasnt all that hard to make and it makes decent bp.

[italteen3]

The AFN IV was an excellent 6 page article on ball milling..i wish i had read that before i bought my ball mill 
      Optimum RPM is 65% of the Critical speed
                                                                                                            Critical Speed= 265.45 divide By Square Root of (jar inner diameter" - milling media diameter")        Sorry I dont know how to use mathmatical symbols on this pc  ....
  EG.. 265.54 divide bySquare root of (6" jar -  1" balls)= 2.236)= 118.712 RPM
So 65% of 119rpm =77 rpm optimum speed for 6"jar with 1" media..

    My Beech Ball Mill Ran at 33 rpm I had some pulley changes which took the speed up to 90rpm which i was going to put up with but having spent so much money i decided to do another pulley change and have now got My 30 lbs of lead media spinning at 72rpm ..
My optimum speed for my 6" jar and .690" media is 75 rpm 
I would definately go the Brass media route..
Also Dont forget if you have optimum rpm you need to charge your jar correctly 50% Media 25% charge(Volume Not weight)..
  Bigger Diameter jars grind Faster than smaller Dia jars..Use lifters bars to make sure your media is not slipping..
  I would Buy the book By Lloyd E Sponeburgh on Ball mill making for lots of tips Etc..

sasman

Just got my dual rotary tumbler in a week before 4th of July. Attempted some small aerial salutes, 9/16" ID 1 1/2" length. Lift was horrible. Im guessing because it burns too slow and I confused something and used large, size of rock candy, granules instead of small... So they went up 5 feet, landed, and went off on the ground, proper safety measures were taken so no injuries, damage (besides my pride ), etc.

About my tumbler each jar has a capacity of 3 lbs. So I loaded about 800-900 grams of media and 100 grams of BP. Sasman you said with optimal rpm jar should be loaded 50% media and 25% charge by volume. Is it ok if the media and charge take up about 1/3-1/2 of jar but media is still double of the charge? Only because if I filled jar 50% with media it would be way over the limits of the capacity and motor without the charge.

I will be figuring out my optimum rpm after and then see what my tumbler actually does to see if this batch was wasted or not.

[chim-chim]

Attempted some small aerial salutes, 9/16" ID 1 1/2" length.? Lift was horrible.? .....went up 5 feet, landed, and went off on the ground

How much lift did you use?

I've found I have to use considerably more lift for these tiny shells than I'd expect.
If I use the 1/10-1/16 shell weight rule, I get similar results. With the small size we're dealing with, the gap around the shell is proportionally much more and the super light shells probably don't do very much for increasing pressure.

United Nuclear suggests 1/8 teaspoon? What good is that? What mesh? Commercial or amatuer? Level, or heaping like they show in the photo? You'd think nuclear scientists would measure by mass, huh?

Using a moderate pulverone, I've used up to nearly shell weight (3-4g for a 5g. shell) in lift to get 35-50 ft. (10+ metres).

Anyone else firing these tiny shells?
If so, how much lift are you using?

If not, give it a go, loaded with 1/4" sections of flying fish instead of a salute, they're great little garden shells, pretty, quiet, and demonstrate how a real shell works in a less scary scale (good for first shells or nervous spouses )


Admins: Off topic I realise, please sort as needed, but being a question to an earlier post, I wasn't sure Italteen would catch a new thread.

Edited by chim-chim, 07 July 2004 - 06:10 PM.

[Greg T]

A word of warning:

I've just bought a rock tumbler from the States (www.pearsons-uslj.com), as I think I'd make a complete mess of things if I tried to construct one myself.

I bought the 33B model which they fitted with a 220V motor (allowing it to operate efficiently in Britain). This cost ?85.

The lady who answered my emails was excellent and she always responded fairly quickly.

I thought the equipment was reasonably priced until I received the package through the post. The website does not warn you of the clearance fees and customs charges that are payable when the package is delivered. These amounted to ?36.06 for the above model.

You've been warned!!

Greg