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Author Topic: rehabilitating 24" Nelson saw  (Read 5165 times)

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robirdman

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rehabilitating 24" Nelson saw
« on: April 24, 2019, 06:10:50 PM »

 I just got the motor repaired and only 28 days left on the warranty.  It runs again. Do I have the belts on right?  The one is very floppy.  There is a spring loaded thing, but it barely reaches and popped off when I ran the saw.  Smaller belt is too loose and floppy.  I remember before I used a weight with rocks pulling down where the spring attaches to the nut, and that worked before but it is still too floppy, as in the blurry shot.  Also the gear mechanism seems to be leaking.  Pictures attached. I Just testing running, no oil or attempt to cut anything yet.  I'm hoping I can get some help and actually cut rocks before the warranty on the motor expires.
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peruano

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Re: rehabilitating 24" Nelson saw
« Reply #1 on: April 25, 2019, 04:43:17 AM »

The "thingey" that jumped off is your belt tensioner. It snugs the belt to insure the correct tension.  Do you have it running on the right belt?  The weight undoubtedly helped maintain that tension too. Make sure you have not used the wrong belts which would cause things to be too loose or tight. Pull that tension pulley down until it snugs the belt and then tighten it enough to make it stay at the appropriate position unless you weight is enough to do so. 
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Stonemon

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Re: rehabilitating 24" Nelson saw
« Reply #2 on: April 25, 2019, 07:39:47 AM »

In my experience, the belt that pushes the blade does not go through the pulley on the feed drive. So the only place the motor powers is the blade. The feed screw is the driven by the second belt off of the blade arbor shaft. The feed screw belt is tightened by the idler pulley.
Running both belts around the feed screw drive with different pulley sizes will lead to thing smoking and jumping around.
Try powering the blade arbor directly from the motor and the driving the feed screw with the other belt. The three different sized pulleys on the feed drive allow you to change the speed of the feed.
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Bill

robirdman

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Re: rehabilitating 24" Nelson saw
« Reply #3 on: April 25, 2019, 07:57:42 AM »

Thanks for the info.  I'll see if there is a smaller belt.  I thought those were the 2 that were on before.
So I'm sure I do the right arrangement, could you include a diagram based on my setup?
Which diameter pulley on this is recommended for Agate/jasper?
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Slabbercabber

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Re: rehabilitating 24" Nelson saw
« Reply #4 on: April 25, 2019, 08:59:08 AM »

Run one pulley from the motor to the large sheave on the blade axle and around the tensioner pulley.  The other belt goes from the small sheave on the blade shaft to the feed shaft pulley.
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robirdman

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Re: rehabilitating 24" Nelson saw
« Reply #5 on: April 25, 2019, 11:59:17 AM »

Running the pulley from the motor to the large sleeve on the blade and around the tension pulley doesn't work. The belt then rubs against that part.
Correct was motor to blade (large sleeve and then the small pulley on the blade shaft to the tension pulley and then to the feed shaft pulley. 
Trying the different combos, I found that then the belts were the right length.  The belt to the tension pulley was not turning it though.  I added oil to the shaft and more weight, and pressing down a few times got it to keep going by itself.  So these suggestions were a great help in finding the right configuration. 
Now my problem is getting the oil remaining in a 55 gallon drum to the saw.  I tried tilting the drum so the small hole in the top would go into a 5 gallon pail but the angle wasn't shallow enough for anything to come out.  I guess I need a long tube filled with oil to be able to siphon it out.  I have some tubing and chain saw oil.  If I pinched the end of a tube and filled with oil, maybe it run out before I put the open end to the drum.  I don't want to suck with my mouth.  Any suggestions? This is all I need to  go.  Big rock in the vise whose cutting was ceased years ago. Feed is working.  Just need to transfer the oil.
Thanks.
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Slabbercabber

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Re: rehabilitating 24" Nelson saw
« Reply #6 on: April 25, 2019, 12:06:46 PM »

Walmart sells a shaker siphon hose for around 8 or 9 dollars.  Drop the shaker valve into the oil and pump the hose up and down until the hose fill with oil.  They actually work very well.
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Stonemon

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Re: rehabilitating 24" Nelson saw
« Reply #7 on: April 25, 2019, 03:26:14 PM »

The idler acts as a safety for the feed screw. If the feed speed is too fast, the drive belt is intended to slip and not create too much pressure at the blade. Good to have a nice solid feed screw pressure but it should not be so tight as to bind the blade.
Grab that bad boy 55 gal and dump that oil in the saw!!  Just Kidding! :toothy10:
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Bill

Stonemon

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Re: rehabilitating 24" Nelson saw
« Reply #8 on: April 25, 2019, 03:30:18 PM »

Thanks for the info.  I'll see if there is a smaller belt.  I thought those were the 2 that were on before.
So I'm sure I do the right arrangement, could you include a diagram based on my setup?
Which diameter pulley on this is recommended for Agate/jasper?

The large pulley on the feed screw at the rear will give you the slowest feed which will move well through the harder materials. You can play with it a bit but my experience is with the slower feed speeds, less wear on the blade and a smoother cut.
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Bill

robirdman

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Re: rehabilitating 24" Nelson saw
« Reply #9 on: April 25, 2019, 04:14:19 PM »

After 30' on hold at the local Wal-Mart, someone came on and asked what I was holding for.  I told and then after another 7' had a dial tone.  Ordering online, said delivery would be May 5.  I looked at Amazon and ordered 1 with a 10' cord, and delivery tomorrow.
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robirdman

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Re: rehabilitating 24" Nelson saw
« Reply #10 on: April 28, 2019, 11:25:08 AM »

So how far should the oil go up into the 24" blade?  Thanks!
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catmandewe

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Re: rehabilitating 24" Nelson saw
« Reply #11 on: April 28, 2019, 07:29:40 PM »

So how far should the oil go up into the 24" blade?  Thanks!

Approx 1/2" or so
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robirdman

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Re: rehabilitating 24" Nelson saw
« Reply #12 on: April 29, 2019, 11:00:18 AM »

The hose came with no instructions.  The only working video I saw showed putting the valve end in the source and shaking and it all poured neatly into the other container, once the flow started.  Other videos only said what to do and one had the non-valve end in the source.  It didn't work nearly as well for me, and I'm not sure why.  I put the valveend in the small hole of the 55g drum and the other into a 5g bucket.  I could never get a continuous flow and had to shake all the time.  The coils of the 10' tube couldn't be completely straightened and I cut off the ends which were pinched flatter.  So maybe it was the coils, the extra length great difference in heights, not being able to see how it was in the drum, but after an hour of continuous shaking and emptying several inches into the saw multiple times, I still hadn't even reached the blade.  Then I had a such a simple idea, I wish used earlier.  I had thought that whatever method, I would just come close to filling the 5g pail and that would be enough, and I couldn't tilt the 55g drum far enough to get any flow.  So I just got a plastic basin that was only about 5 inches deep and poured into that 4x, and emptied and got past 1/2" and turned the saw to cut. It looks like it may take about an hour.  Timing for future reference and hope nothing goes wrong.  Thanks for all the suggestions!
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Slabbercabber

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Re: rehabilitating 24" Nelson saw
« Reply #13 on: April 29, 2019, 05:37:47 PM »

The outflow end of the hose must be below the level of the source.  Once started the fluid will flow until the two containers have equalize levels.  A bucket on the floor with a weight to hold the hose down should work.
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robirdman

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Re: rehabilitating 24" Nelson saw
« Reply #14 on: April 30, 2019, 06:47:17 AM »

I successfully cut a couple of slabs off the rock in the saw.  Each was taking maybe 90'.  Then the next piece I checked and it hadonly moved less than and inch.  I checked that the fee pulley was going and the feed screw turning, and continued.  It is no longer feeding.  I looked at the long threaded feed bolt in the saw, after moving the vice and saw no problems.  Maybe the threads on the vise apparatus are stripped.  Hopes dashed.
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