1rockhound
spending too much on rocks
Member since July 2008
Posts: 286
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Post by 1rockhound on Jul 26, 2008 1:40:28 GMT -5
I bought this tumbler today and was wondering if anybody has heard of the brand "Nelson"? I looked online but could not find any info. Also do I need to get a smaller pulley? The motor is a 1725 with a 1 1/2 inch drive pulley and the driven pulley is a 16 inch. The barrels are 1 gallon and are making 9 revolutions a minute. The reason I ask is I have never owned a tumbler before and I'm not sure if it is going to slow? I picked this up for the same price I would have paid for a new Lortone 33b. |
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Post by Jack, lapidaryrough on Jul 26, 2008 6:46:25 GMT -5
Nelson Lapidary, Make`s some of the best Equipment, The lapiday saw by Nelson is as good if not better then a old Highland-Park.
Small barrels should run at about 45 RPM.
Though the Nelson Company know`s what is best for the right RPM for the design of that model.
Myself i have a 24"x10" octagon barrel, Geared to 16.5 RPM though i run 70 Lbs. in it for coarse run.
Good to see old lapidary equipment that has been taken care of.
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knapper42
starting to shine!
Member since March 2008
Posts: 36
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Post by knapper42 on Jul 26, 2008 7:53:24 GMT -5
In case you haven't already calculated it, you tumbler is running about 162 rpm.
knapper
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Post by Condor on Jul 26, 2008 8:49:54 GMT -5
You have never bought a tumbler before and you end up with that?!!! Way to go! Don't know about the speeds or anything like that, but geez, it looks like everything will turn out just great.
Condor
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Post by johnjsgems on Jul 26, 2008 10:03:55 GMT -5
I'd leave the pulleys as designed. Drums for that style tumbler were made by Thumler's and Scott Murray. You can measure the liners and see which one. The Thumler's dimensions can be found on the Diamond Pacific site as their 12 lb tumbler. If the dimensions are different I think Kingsley still carries Scott Murray. You've got a great set up there.
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1rockhound
spending too much on rocks
Member since July 2008
Posts: 286
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Post by 1rockhound on Jul 26, 2008 11:08:20 GMT -5
Thanks for all of the replies. The condition of the barrels is quite good as the previous owner only used sawdust in them to tumble brass.
My son and I loaded the first barrel this morning with some Pink Plume Agate, Some really cool Agatized Bog Wood, a couple pieces of Picture Jasper and some Bruneau.
I am glad that I have access to a lot of rough material around here to fill the beast.
Now lets see how my first batch will turn out!
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Post by connrock on Jul 27, 2008 5:44:26 GMT -5
I have to disagree with John on the speed of your tumbler.
Nine rpm's sounds way too slow for that size barrel..
Here is some discussion on barrel speeds from Hale Sweeney,,,
From: Hale2@aol.com
Date: 22 Nov 1995 17:57:40 -0500
Subject: Tumbler Speeds (edited, corrected)
To: ajs@hpfcajs.fc.hp.com
RPM(round) = 132.8 / sqrt (diameter in inches)
RPM(hexagonal) = 79.7 / sqrt (diameter in inches)
Or (original form):
RPM(round) = 54.2 / sqrt (radius in feet) * 0.5
RPM(hexagonal) = 54.2 / sqrt (radius in feet) * 0.3
...the name of the booklet is TUMBLER'S GUIDE, ...published
about in 1960.
(From ajs:) So my tumblers should run at 66.9 RPM and 30.4 RPM,
respectively. Some observed numbers for barrel rotation speed:
Lortone 2.5lb tumbler: 52 RPM (22% "low")
Lortone 12lb tumbler: 28 RPM ( 8% "low")
Thumler 12lb tumbler: 22 RPM (barrel about same size as Lortone 12lb)
connrock
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Post by catmandewe on Jul 27, 2008 23:12:41 GMT -5
Hey Jason,
Thats a heck of a first machine. Nice find!!
It doesn't get much better than that...................Tony
PS I went out and timed my thumblers 15 pounder (the barrels look just like yours) and it makes 14 full revolutions per minute, if that helps any.
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1rockhound
spending too much on rocks
Member since July 2008
Posts: 286
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Post by 1rockhound on Jul 28, 2008 3:10:47 GMT -5
I checked the barrel this evening and it is grinding the rocks but I will see how much it grinds by next week. I think I will get a 8 inch pulley and try that as I should get 18 rpm. I guess it will be trial and error until I find what works.
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Post by Noosh9057 on Jul 28, 2008 6:50:51 GMT -5
Wow what a great first tumbler.
Roger
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Post by johnjsgems on Jul 28, 2008 9:25:37 GMT -5
It would cost less to try a larger motor pulley. If you can find a variable sheave you could have some adjustment. Better yet a 3-step pulley on the motor. Increasing the speed will increase motor amperage and rock chipping. If it looks all original I wouldn't worry about it until you run a batch or two and see how it works. My opinion.
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Post by connrock on Jul 28, 2008 16:03:28 GMT -5
Hey John, I'd try a load too to see how things go but it seems too slow to me. It seems to be about 1/2 speed for that size and configuration of barrel?  ? By the way,,,, I'm NOT trying to start a battle of the minds here.Just adding my 2 cents worth!(it's good to "air out" the old brain now and again)! LOL connrock |
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Post by johnjsgems on Jul 28, 2008 17:40:11 GMT -5
No problem. I spent most of my life "fixing things". Now I'm a firm believer in "if it ain't broke, don't fix it". Most people don't have a clamp on amp meter to check their motor current draw and find out after changing pulleys and belt that the motor is overloaded when the motor trips an internal thermal overload or (on older non-protected motors) burns up. Then they have to try different combinations of pulleys until it works. Those are 12 lb barrels by Highland Park/Diamond Pacific label or 15 lb. by Thumler's reckoning. Either way that's quite a load if all three barrels are loaded. Another thing to check before changing pullys is the shaft covering. They are usually covered with lengths of braided hose. That helps the barrels get a grip and cut down on slipping. That will speed it up slightly also as the overall shaft diameters will be slightly thicker.
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