Lapidaryforum.net
Gadgets, Gizmos, and Dohickeys => Fixing, Modifying and Refurbishing your Lapidary Equipment => Topic started by: Grayco on January 09, 2017, 01:42:04 PM
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Greetings Everyone,
My name is Glen. I live in Washougal Washington and I am returning to the lapidary hobby after 50 years.I recently bought a BUNCH of old lapidary equipment from an estate. All of it needs work. I am an industrial mechanic by trade, so I'm not worried about fixing old equipment.
Does anyone here recognize this 12" saw? It's kind of cool. The vice rotates into the blade. The problem here is that the shaft the vice is on, has fine threads (allows for adjustment of the slab thickness). The shaft and the vice seem to have become one piece and the shaft no longer turns inside the vice "nut" . So far, brute force and ignorance have not prevailed. I am going to remove the whole assembly and with a workbench vice and a torch, I believe I can get the vice to adjust again.
Let me know if you have any experience with this type saw.
Thanks
Glen
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Sorry can't help you but wanted to say hi to another Washingtonian. I'm on Whidbey island.
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That has to be the strangest saw I have ever seen.Hope you can post some more pics so we can see the movement mechanisms.
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Hi from Eastern Washington! I love to restore old equipment. I'm working on a saw, Cassette Tape Deck, and a milkshake machine right now.
That saw looks home made to me. If I figure right, the vise clamps the rock and rolls across the blade as it cuts with gravity. Interesting design. I'd be very interested to see it work. My biggest fear would be binding and destroying the blade, but YMMV.
Plenty of penetrating oil and elbow grease should beat it apart. You'll probably have to replace every thing on it with threads and the bearings. Does it have a lid?
Joshua
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That saw looks home built to me.
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Hello again Everyone,
I'll post more pictures later today but I thought I would give you a little more information about this saw.
I finally got the vice and screw separated. It did take a shop vice and a torch.
The large fine thread screw that the vice is on, and the blade shaft are both run through bearings in a single casting. This casting does not look homemade. The vice however does have some homemade features. (I broke it trying to get the vice and screw apart)
The vice plate on the right, slides toward the fixed position vice plate (anvil) on two 1/2-20 screws. It appears if your rock is smaller than the vice pad (about 4") you would have to use pieces of wood between the vice plates to secure the rock.
While wrestling with the vice assembly I put too much pressure on the sliding vice plate. one of the ears, that the 1/2-20 bolts go through, broke in half. Turns it was silver soldered to the plate. The 1/2-20 nut on the other side of the plate broke off the underside of the vice pad (again silver soldered).
The rock feed is actually power fed from a small gearmotor on the side of the saw not visible in the picture.
You may notice a homemade looking thumb screw at about 3:30 on the blade. That locks the vice in position on the large screw.
With that screw loosened, you can crank a handle attached to the outside end of the large screw and move the vice on the screw.
With that thumb screw tightened, turning the handle rotates the vice into the blade. With your rock close to the blade you can pull the handle laterally (its spring loaded and has pins engaging it into the large screw) in order to align the handle with a nut on a drive screw which is powered by the small gearmotor.
I currently have the saw in pieces. I'll take a few pictures and a few more after I get it back together.
For $30 I couldn't resist it.
Just wait until I show you the 20" saw I got for $50! I've worked on it enough to get the slide freed up and both motors running. (I'll start a separate post with pictures after I get this little 12" back together)
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Pictures as promised. :occasion14:
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Forgot one more
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Good Earth,
After really looking at the feed system on this saw, I believe you are correct. I think the original design was for the feed to be hand/gravity feed.
I think the incomplete drive system was a modification someone started many years ago. Here's some of my thoughts about that:
When the cut is first started, there will be very little gravity influence on the feed and a little manual pressure is probably required. As the center of gravity passes the top center, gravity's influence increases. Towards the end of the cut, the drag from the blade, below blade center, probably adds to the feed pressure. The smaller the rock is, the sooner blade drag will influence feed pressure.
I think for now, I just need to run it and see how the feed works. If I find the feed really needs assistance for the feed, I'm thinking something like a bungee cord to pull the vice past the center of gravity may be all that it needs.
Does anyone have any thoughts on how the changing feed pressure may effect cut quality?
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Could that long bolt sticking out near the top of the clamp be something a weight hung from?
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Could that long bolt sticking out near the top of the clamp be something a weight hung from?
No. That is just a bolt to limit the rotation of the vise. Hmmmm... maybe it could be useful for that
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I just got a 12 inch gravity feed saw going. It takes 22 pounds of sand to cut without too much load on the motor or blade. It looks like it would be very easy to make that one a gravity feed. That might work better than that BBQ motor set up.
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I just got a 12 inch gravity feed saw going. It takes 22 pounds of sand to cut without too much load on the motor or blade. It looks like it would be very easy to make that one a gravity feed. That might work better than that BBQ motor set up.
Wow, 22 pounds.... I would have thought half that would have been too much. OK I think you are right. A gravity setup will be an easy fix. You are also right that that motor is a BBQ motor. I didn't realize it until you mentioned it.
Here's a quick update on progress. Upon inspection I found the spindle bearings are bad. I have ordered two new bearings (S7PP) from "Bearings Direct". They were a third the cost, of any other bearing supplier, and they use USPS fixed shipping. $6.95 for "If it fits, it ships" shipping. I have also been working on fixing my broken vise. This next I'll weld a plate onto the back plate and re-weld the nuts on the bottom of the vice.
In the mean time, I've started revamping my HP F1 trim saw. I had an old Korean made 1" belt sander ($5 garage sale treasure) that was missing pieces. I salvaged the metal base and the 1/3 hp 1720 rpm motor. The motor is going to go on a 12" polisher I bought for $50. I am using the base for the HP F1.
I have mounted a 1/4hp 1740 rpm motor on the base. I have disassembled, cleaned and reassembled the saw and today I will mount the saw on the base. I still need to get a nice electrical box and switch, make a belt guard, replace a broken splash guard and re-mount the blade ?fender?. It appears a 6" blade will fit this saw but the saw table seems to fit a 4" blade better. I'm still working on that.
Anyone know about a Model T Rock Rascal combination unit? I have one that is missing the table and stone shroud. Any thoughts on a good stone choice for this unit?
Thanks for all your inputs
Glen
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I admire your energy! Your rock shop will be humming in no time at this rate!
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You sound busy. That 22 pound weight has to pull a vice along two rails. There's a lot of resistance there to overcome. You might need less.
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You sound busy. That 22 pound weight has to pull a vice along two rails. There's a lot of resistance there to overcome. You might need less.
I was thinking the same thing. With set up, gravity will be pulling the rock and vise into the blade and there are no slides so I'll start light. What kind of feed rate should I be targeting? My test rock will probably be a piece of quartzite.
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Make sure you have a GFI plug on there somewhere. I never trust GFI breakers and use a plug close by. good luck
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To find the right amount of weight, I put a piece of mariposite in the vice and attached the hand scale I used to weigh llama packs with to the cable. The scale has a hook on one end, a handle on the other, and the scale dial in the middle. I think it started out as a scale to weigh fish. I started the saw and pulled. At 22 pounds it was cutting nicely and it didn't sound like the motor was bogging down. Then I put 22 pounds of sand in an old paint can and hooked it up. Works great.
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Progress update;
I have cleaned this saw up and discovered the spindle bearings were bad, so I replaced them. I do believe this saw was homemade but the builder was a talented craftsman. He was certainly a good machinist but I suspect he was an industrial mechanic as well.
I found Babbitt between the spindle bearings. There aren't many folks who would even know what Babbitt is, now days.
The spindle/vise support assembly was installed with the long side on the outside of the box. That did provide more room for the vise to adjust, but it made it nearly impossible to align the drive belt. I mounted the assembly with the short side out. The belt lines up easily and I think it looks better.
The blade fender was made of brittle plexiglass and broke apart. With the spindle/vice support mounted differently, the location of the fender no longer works. I will probably forget the fender for now and work on a cover to cover the whole box. The box is 12" x 18" so I may luck out and find something that is the right size and can be easily modified to work.
I believe if I remove the bolt on the vise that keeps the vise from rolling to the bottom of the box, I will be able to roll the vise below the level of the top of the box. This will allow me to set a flat top on the box and use this as a trim saw too. That is when I will need a blade fender.
I have a plan for a feed mechanism. Gravity feed is a good option, but with this saw I only need to rotate a shaft 90 degrees to get a full cut. My current plan is to put a bicycle sprocket (about 3") on the lock collar just behind the handle and use a chain attached to an extension spring to rotate the vise. I think I can select a spring that will provide about 20 pounds pressure to the cut and decrease pressure as the cut nears it's end. Time to scrounge parts. For now this saw is going on the shelf and I have started cleaning up my 20" saw. I am going to start a new thread on it.
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What is that mass hanging underneath? Could that be a rotary sludge separator? If the spring idea doesn't work out, there are dozens of sources for small gearmotors. Barbecue and Erector set motors come to mind.
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What is that mass hanging underneath? Could that be a rotary sludge separator? If the spring idea doesn't work out, there are dozens of sources for small gearmotors. Barbecue and Erector set motors come to mind.
The mass underneath is an oil reservoir. I described it with pictures in my post titled 20" saw project. I posted that yesterday.
As far as the drive system, this saw had a BBQ motor mounted on it. The whole system was ugly and funky and was not complete. (see the earlier pictures). Keeping in the spirit of keeping it simple, I really think the spring and chain system will be cleanest.
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In response to your query as to a desired feed rate, I'd guess that most slab saws are aimed at 4-7 minutes per inch. Slow is good in terms of blade life and motor life. Many folks who hand feed trim saws or tile saws in trying to cut slabs (or anything more than trim) probably crowd their blades excessively (its too painful to go real slow). I"ve used a water bottle as a weight and can easily adjust weight as needed. I'd start with a small and probably soft rock to get a feel for how it cuts and the proper setup.
On a separate issue, the Model T rock rascal is a common trim saw (and combo unit). Pictures should abound. I have posted one that I'll have to look for the url. The wheel for the grinding end is a 6", but I believe the water tray is a bit narrow for an expand wheel which would be ideal, but I'd check that as a possibility.
I borrowed a small motorcycle fender for a blade shield for my homemade saw, but a bike fender would work as well.
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Here's a Model T with a narrow wheel on it. I fabricated the belt guard. (http://i275.photobucket.com/albums/jj311/rababikes/lapidary/DSCN2368_zps2b70da5f.jpg) (http://s275.photobucket.com/user/rababikes/media/lapidary/DSCN2368_zps2b70da5f.jpg.html)