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Author Topic: rehabilitating 24" Nelson saw  (Read 5127 times)

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robirdman

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Re: rehabilitating 24" Nelson saw
« Reply #30 on: September 12, 2019, 01:02:50 PM »

I try to get 2 closest to the left one, thanks.
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robirdman

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Re: rehabilitating 24" Nelson saw
« Reply #31 on: September 13, 2019, 04:39:59 AM »

Looked up McMaster and what a great resource!.  I had a metric ruler and measured, but then saw all their measurements were in decimal fractions of an inch.  I thought maybe I needed a micrometer or something, and maybe I could send to them to get the right type.  Then I see the address in Elmhurst and my phone shows as only 48' away! So I can just bring it there, validate type, gauge, etc!
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robirdman

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Re: rehabilitating 24" Nelson saw
« Reply #32 on: September 13, 2019, 07:28:59 AM »

Unfounded optimism.  Called and just a will call warehouse, can't look at anything.  I need a micrometer for accurate measurement of the gauge wire.
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robirdman

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Re: rehabilitating 24" Nelson saw
« Reply #33 on: September 18, 2019, 04:54:08 AM »

While not a micrometer, I found I had a device for reasonably accurate measurements, sort of like a slide rule, with the sliding parts capable of measuring inside and outside diameters.

It seemed pretty standard.  OD 3/4", ID 9/16" length 1" , wire diameter ~3/32", compression spring, steel I assume, end typ flat and ground.

So I plug into the McMaster chart most of the info, and there are only springs longer than 3" showing.

I use the email to convey this and "I'm sorry, but we don't sell compression springs with the combination of specifications that you need."

So I guess that is why one of the springs looks cut and modified. The whole operation of this saw held up because of this simple need.
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Slabbercabber

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robirdman

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Re: rehabilitating 24" Nelson saw
« Reply #35 on: September 18, 2019, 11:50:27 AM »

Thanks for the link.  Unfortunately, it seems that for 1" L, 3/4" OD, the ID is 3/8" for a 3/16" rod, while my rod is 3/8" and there would be no play.  But McMaster sent another email with a link to some that are closer, also that they can custom make them,, but that costs hundreds of dollars.

Using the fractions on the page, my measurements become OD .75",  ID .5625"  wire thickness .09378

On this page some are close in some aspects, and not so close in others, while others have a different close/not so close relationship.  I'm wondering which is most important.  https://www.mcmaster.com/compression-springs/=2b1ef529b9da4bbaad8102baf170fe33k0pa9m4t
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catmandewe

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Re: rehabilitating 24" Nelson saw
« Reply #36 on: September 19, 2019, 09:32:49 AM »

I would order an assortment of the ones that I think will work and then test fit them until I find the one that works the best.
You can try to get it on the first shot but if you dont you will spend more than that in shipping costs, might as well have extra springs on hand rather than having to pay the extra shipping costs to try the next two or three springs.

Tony
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robirdman

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Re: rehabilitating 24" Nelson saw
« Reply #37 on: September 25, 2019, 10:49:23 AM »

Who would have ever thought that it would be so hard to match a spring when a company has hundreds of varieties. 
I chose the 3 that looked closest in specs, from McMaster.  In the picture, at the left, are the 2 current ones, one of which maybe was original and a later substitution.  Then the 3 new springs.  One hopelessly loose, another lighter gauge than the current, and another so thick that I don't know if I could even compress it enough to get in the mechanism. 
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hummingbirdstones

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Re: rehabilitating 24" Nelson saw
« Reply #38 on: September 25, 2019, 06:08:21 PM »

I suggest you call Cigar Box Rock in Bend, OR and find out if they have a spring to fit your saw that you can buy from them.

https://cigarboxrock.com/
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Robin

robirdman

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Re: rehabilitating 24" Nelson saw
« Reply #39 on: March 08, 2020, 02:50:03 PM »

The saw has been dormant during the winter, after none of the springs matched.  With the warm weather today, I filed some material off the 2 sides at the top of the split nut, where the separator.  I put this back on the saw's threaded bolt to see how it fit and it was pretty good, so I opened and moved to the platform to bolt on.  It seemed that the holes didn't match up well.  I bolted the far side but then the closer side was off.  It didn't seem like the opener was not in the middle, but I figured I must try turning the split nut assembly around.  I had been able to put the split nut on the threaded bolt before and then assemble the rest of the apparatus, using pliers to squeeze the spring, but now I couldn't get the springs out and had to open and pull with pressure off the threaded bolt.  I turned the apparatus around and now its holes matched much better with the platform, though it seemed that the split nut sides were less symmetrical. so I set it to run with out the vise or rock as a test.  It successfully went about a foot in an hour and then I tested again to make sure it hadn't stopped at that point.  So now I went to pull the platform back.  It made a grating noise as the split nut, though open was rubbing on the threaded bolt.  I added a washer on each side to raise it slightly, and now it didn't rub. It looked more lopsided now. Ran a test and now the platform didn't move at all.
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lapidaryrough

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Re: rehabilitating 24" Nelson saw
« Reply #40 on: March 08, 2020, 06:43:37 PM »

Copy a Frantom 24'' saw.
For correct pulleys  needed.

https://www.govdeals.com/index.cfm?fa=Main.Item&itemid=723&acctid=4788

Jack
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Downwindtracker2

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Re: rehabilitating 24" Nelson saw
« Reply #41 on: March 28, 2020, 12:10:32 PM »

If you find a too long spring that looks like it might work, you can cut them shorter with a Dremel .
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