Minnesota Daniel
freely admits to licking rocks
A COUPLE LAKERS
Member since August 2011
Posts: 891
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Post by Minnesota Daniel on Oct 5, 2011 1:13:10 GMT -5
Does anyone here have experience with one of those older Craftsman lap grinders? I see used ones for sale from time to time on Craigslist. I don't understand how it would work, but they are described as a flat lap and a saw. A horizontal saw? Are these units any good? They look sturdy, if kinda primitive. They seem a lot less expensive than other used flat laps, or smaller wheeled grinders. One day I will have a big rig with diamond wheels, I'm sure of that, but until I can afford it, is one of these units worth considering? Advice anyone?
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blarneystone
spending too much on rocks
Rocks in my head
Member since March 2010
Posts: 307
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Post by blarneystone on Oct 5, 2011 9:14:24 GMT -5
Hi Daniel.. I don't have any experience using one... yet. I bought a used one from a guy out in CA. but I haven't assembled it yet. It looks to be a very solid machine, built to last forever as most old Craftsman tools are. I have the manual and would be happy to scan it for you so you can see how it would operate as a saw. As soon as I get it assembled I'll take some pics.
I don't know that I would want to use a flat lap for cabbing though. I learned to cab on a GP-6 and I think it would be very difficult to cut cabs on a flat lap but I have never tried it myself.
I'm hoping to get it assembled this weekend so I'll post some pics then.
Dan
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Post by mohs on Oct 5, 2011 10:38:22 GMT -5
I like to see a picture of this Craftsman does it come with a green flat lap wheel?
I have WoodCraft flat lap machine that was made for sharpening planer blades. It came with a green wheel.
I was able to buy a diamond flat disc 120 grit and use it on this machine, The speed is about 700rpm makes for a real inexpensive flat lap being that I paid 35.00 for this used turntable
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Post by frane on Oct 5, 2011 14:21:23 GMT -5
I don't know about the craftsman but I had an Inland flat lap when I started out. Hardest thing ever to get a good dome on cabs. always ended up with flat spots. Each machine is different and has its own characteristics. The Inland has a motor that over heats fast so it quits when you are not ready to stop. The swapping of the saw to the flat lap is not that easy and if you don't tighten the arbor just right with the flat lap, you can ruin the machine because it will slip and ride on the plastic tray lip and grind it down so water leaks into your motor. Hard as I tried, I still did that twice and had to buy 2 motors! The craftsman may be built better. I have never heard of one but if it uses water, you should be OK with an additive. In all honesty though, If I could start over, I would have just saved my money and gotten a wheeled cabber. I ended up grinding the shape wanted and throwing the hard enough cabs into the tumbler or vibe to finish the shaping and smoothing. Then I could polish them on the flat lap. What ever works for you is what counts! Fran
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rocpup
spending too much on rocks
Pink Limb Iris
Member since March 2011
Posts: 465
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Post by rocpup on Oct 5, 2011 15:05:13 GMT -5
I started out cabbing on one of these units back in 1963. I think I made maybe 15-20 cabs with it. It came with a saw blade and it had a vise to hold a rock and you pushed it through by hand. The vise was then lowered by a screw feed to make another cut. A grinding wheel was also supplied. You had to take the saw blade off and put it on. The grinding took place on the side of the wheel. After a while it got grooved and bumpy. It was a low dollar unit and was all I could afford at the time and it served me well. Don
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Post by Rockoonz on Oct 6, 2011 5:33:52 GMT -5
I have one with a weight feed for the saw vice. What I wonder is how long saw blades would last since you only drip water onto one side of the blade when cutting. I am thinking about modifying the saw vice into a clamp to hold pieces square and parallel when lap grinding pieces for intarsia and inlay work.
Lee
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Post by jakesrocks on Oct 6, 2011 8:25:45 GMT -5
With a good backing plate and diamond disks, you could convert it to an all diamond unit for grinding the flat backs on cabs. Those older units were very sturdy, and will outlive most of the newer flat units.
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blarneystone
spending too much on rocks
Rocks in my head
Member since March 2010
Posts: 307
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Post by blarneystone on Oct 6, 2011 8:41:38 GMT -5
Ok... I scanned the manual to a .pdf file and will be happy to send it to anyone who needs it. The model I have is a Craftsman 1401 Gem Maker, I'm guessing it's at least 40 years old, maybe even older.
If you'd like a copy of the manual, please sen your e-mail address to me in a private message and I'll send it on.
Dan
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Post by jakesrocks on Oct 6, 2011 9:28:49 GMT -5
I'd like to see the Mods set up a separate thread for instruction manuals like Dan has. It would be a great resource for any of us who are using or rebuilding older machines. I have a couple of old manuals that I could add. Don
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Minnesota Daniel
freely admits to licking rocks
A COUPLE LAKERS
Member since August 2011
Posts: 891
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Post by Minnesota Daniel on Oct 6, 2011 12:24:58 GMT -5
Thanks for the input guys. I have an MK 170 tile saw that I use for cutting, and wasn't really thinking of getting this unit to replace that unless it was an improvement.
For grinding I have a couple needs. 1) I'd like to be able to preform tumbling rough -- get the sharp ridges and points off. A wheel sounds like the right option for that. 2) I'd like to shape and dome cabochons to the point where I can at least put them in the 500 grit and let the tumbler do the rest. Or if it's a real flat lap, make cabs with it, beginning to end.
So as I now understand it, this comes with a horizontal (probably SiC) wheel, and not a backing plate and diamond lap disks. Is that right? That would be a big difference. How hard would it be though to just plop a backing disk and diamond lap on top of the wheel? Maybe some kind of a spacer instead of the wheel? That hardly seems like it's even a modification. Is it the right speed for that? I suppose it wouldn't be too hard to change the pulley though.
It comes with what appears to be a rather large, clean, Craftsman motor (not in this photo). Does that have a significant value by itself? I mean like to attach it (later) to a used wheeled grinding unit that doesn't come with a motor.
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Post by jakesrocks on Oct 6, 2011 12:44:06 GMT -5
Daniel, what is the arbor size on that unit ? If it's 1/2", any 6" or 8" lap backing plate and diamond laps will work, and would be a big improvement over a silicon carbide grinding wheel. But you will need to use that backing plate. The diamond laps are too thin and flexible to be used on their own.
What HP is that Sears motor ? If it's 1/3 HP or greater, it could also be used for a vertical grinding unit. As for speed, you'll have to work that out with pulleys. The motor is probably a 1725 RPM.
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Minnesota Daniel
freely admits to licking rocks
A COUPLE LAKERS
Member since August 2011
Posts: 891
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Post by Minnesota Daniel on Oct 6, 2011 13:24:04 GMT -5
I'm not positive on these details, but I believe the motor is 1/4 horse, and the arbor is 5/8". Could I safely drill out the hole in the flat lap disk?
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NDK
Cave Dweller
Member since January 2009
Posts: 9,440
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Post by NDK on Oct 6, 2011 19:26:59 GMT -5
I'd convert that to diamond in a heartbeat, Daniel. Cabbing is definitely doable on a unit like this, and when set up right, it's fairly painless. I only have a flat lap I built myself, and cut all my cabs on it. I'm no expert, but I think they turn out OK ;D I got my diamond discs and backing plate from the rock lady. They are great quality, and a good price.
Nate
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Post by jakesrocks on Oct 6, 2011 19:41:33 GMT -5
I'll have to check some catalogs, but I think backing plates and disks can also be ordered with a 5/8 center hole too. I wouldn't try to drill them bigger. All you have to be is just a little bit off center, and you'll have one hell of a vibration.
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Post by Woodyrock on Oct 6, 2011 23:58:10 GMT -5
These old Craftsman units were actually B & I Gem Makers. In the mid sixties they were about $35.00 with all the goodies. They have a 1/2" shaft and will take diamond plates. We still have the eight inch one that my wife uses mostly to flatten the backs of cabs for triplating opal. I use it to preform obsidian for knapping. Woody
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