jamesp
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Post by jamesp on Mar 3, 2018 6:41:28 GMT -5
This will be an 8 inch flat lap of welded construction from carbon steel materials. May end up being a rust bucket but flat laps do not look clean very often. OK. Stock of 1/2 inch pillar blocks, 1/2 inch pulleys, 1/2 inch shaft and 1/2 inch shaft collars was already on hand in the parts bins. Got a 1/2 inch bore 8 inch aluminum backing plate on order from Ebay for $29.95 and a bunch of $12 diamond plates also 8 inches. The focus component will be a 14 inch elliptical pressure tank bowl at a weldable thickness of 1/8 inch. The shaft will enter offset from the center of the bowl and have a welded collar vertical in inside of bowl to keep over flow water from going down the 1/2 inch drive shaft entry hole. A threaded 3/4 inch drain will be welded to the center of the bowl on the bottom so a common garden hose can be connected to it to serve as drain hose. A vertical plate will be welded to the bottom of the bowl to serve as a mount for the two pillar block bearings. Yet another vertical plate may be welded to the bottom of the bowl to serve as the motor mount. Tripod legs wil be welded to the bottom of the bowl, height yet to be determined(table top height or free standing floor height. Probably floor height so it can be moved outside on pretty days. A dripper container will be welded on with small drip valve. A lip for a hand rest where lap blade is close to edge of bowl. A lip for the dripper container. And any other lips needed such as water management. Intention is to have an integral unit with motor attached to unit. May regret if vibration is an issue. Target speed. 1/4 HP 1725 RPM motor with 3:1 reduction ratio(575 RPM at blade) should be more than fast enough with 8 inch blade with 24 inch(2 feet) circumference. That equates to about 1200 feet of travel in one minute, so booking along. Lots of grindability at that speed. Model to duplicate is Drummond Island Rocks's sweet looking vintage lap in this photo: These are the components I have laying around. Motor and legs not shown. Weldments either. The 4 inch cast iron pulley will be used to support the backing plate. I will drill and countersink backing plate to this 4 inch pulley. Please wish me well.
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Post by gmitch067 on Mar 3, 2018 7:35:52 GMT -5
As the slurry spins off and contacts the side, wouldn't the curvature deflect it upward slightly and cause the mud to climb up and out?
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Post by Drummond Island Rocks on Mar 3, 2018 8:46:27 GMT -5
Do you have a source for powder coating? That would keep it looking good for awhile. I gave you pictures from the top before but here is a picture of the bottom if that helps at all. Chuck
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jamesp
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Post by jamesp on Mar 3, 2018 10:28:14 GMT -5
As the slurry spins off and contacts the side, wouldn't the curvature deflect it upward slightly and cause the mud to climb up and out? I hope to weld a full circumference lip around the edge - or only as needed after watching where the water goes gmitch067. I do want to lower the lip as low as possible at the grinding zone for best access and palm rest without getting wet. For sure, will modify as needed for water management - top priority. No more rain coats
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jamesp
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Post by jamesp on Mar 3, 2018 10:37:20 GMT -5
Do you have a source for powder coating? That would keep it looking good for awhile. I gave you pictures from the top before but here is a picture of the bottom if that helps at all. Chuck Thanks for that detail. I kind of imagined that was the bottom. Is the drain in the low spot of the tub ? I do want the water to drain completely out. I was going to target the low spot to drain the water on this bowl. And have the shaft enter about 5 inches from the edge so the lap access is closer to the edge. No less than 5 inches to avoid a finger nip point. One inch gap... That would put the shaft entry hole 2 inches from the lowest spot in the center. Bowl is 14 inches, minus 5 inches is 2 inches. I got tired of wrestling rust down here Chuck. Our humidity could rust gold. Let er rust. I may install a rain roof for the motor. As it may spend more time outside.
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Post by Drummond Island Rocks on Mar 3, 2018 12:36:18 GMT -5
The gemlap flat laps originally came with a lip that rested on the top rail. Chuck
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NDK
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Post by NDK on Mar 3, 2018 19:42:11 GMT -5
James, this is just a thought, but if you cut out the bottom of the bowl, invert it & reweld you'll have a built in guard to keep the water off the shaft & move the lowest spot outward for easier mounting of the drain.
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jamesp
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Post by jamesp on Mar 3, 2018 22:18:50 GMT -5
James, this is just a thought, but if you cut out the bottom of the bowl, invert it & reweld you'll have a built in guard to keep the water off the shaft & move the lowest spot outward for easier mounting of the drain. NDK How about a 3/4" to 1" water pipe welded to the inside of the bowl with the shaft going up the pipe to protect it from water ?
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jamesp
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Post by jamesp on Mar 3, 2018 22:21:30 GMT -5
The gemlap flat laps originally came with a lip that rested on the top rail. Chuck Do you rest your hand/palm on the lip when grinding ? Your laps are made out of that nice aluminum. Nice well made vintage flair to those units.
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Post by Drummond Island Rocks on Mar 4, 2018 9:22:44 GMT -5
The gemlap flat laps originally came with a lip that rested on the top rail. Chuck Do you rest your hand/palm on the lip when grinding ? Your laps are made out of that nice aluminum. Nice well made vintage flair to those units. Yeah what would equipment built like that cost these days? I have a couple of their trim saws too. They pieces of art compared to the stamped steel crap being built now. I can't help with the use of that ring/rest. I do not use them. Here is the matching trim saw Chuck
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Post by Drummond Island Rocks on Mar 4, 2018 9:42:00 GMT -5
I like the drawing above. Looks like it should work. Are you planning on fabricating the shaft and flange? That is the most important part of the project in my opinion. Very tight tolerance on that flange being exactly 90 degrees to the shaft. I am not sure if the Lortone saw shafts are one piece or a welded flange A machined step like this one on my Trim saw cabber unit works great too. A slip on flange goes over the stepped down portion and just rests up against that shoulder. No wobble at all. So you could just have a 3/4" shaft made and have the last 2" stepped down to 1/2" then have them thread that portion to 1/2-13.
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jamesp
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Post by jamesp on Mar 4, 2018 9:50:34 GMT -5
Do you rest your hand/palm on the lip when grinding ? Your laps are made out of that nice aluminum. Nice well made vintage flair to those units. Yeah what would equipment built like that cost these days? I have a couple of their trim saws too. They pieces of art compared to the stamped steel crap being built now. I can't help with the use of that ring/rest. I do not use them. Here is the matching trim saw Chuck I look at my Viking Vibrasonic and slant tumbler and marvel at their construction as you obviously do your vintage machines. Appreciation for well made machinery is addictive especially if you can own it and produce products with it. Comparing tin can Lot-O to Vibrasonic - junk verses poetry, But, that Lot-O has higher level of technology behind it so it deserves a bow regardless of the tin can construction. It smokes my $1500 Vibrasonic in the finishing department which is the #1 goal of a vibe. One is 50 year old technology and one is new technology. New trumps in this case. I did lay my lap bowl out on the rotary table and begin layout. Cut plates out for motor and pillar blocks. Drain plug and shaft pipe. Motor and bearing plates will be welded directly to 14" bowl so very compact. I hope with motor attached it does not set up vibration. If it does it will get the torch and the motor will be isolated like yours and Tommy's. Looking at tripod legs at chair height, stand alone, wheels on 2 legs so I can roll it outside to grind as I may be making many pounds of glass mud each sitting. Will weigh 40 pounds plus when complete. But heavy duty like them vintages. The 4 inch cast iron puller w/the white sticker on it will be the backer rest Chuck. It is precision 90 degree with long bore 1/2 inch hole.
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Post by Drummond Island Rocks on Mar 4, 2018 9:51:20 GMT -5
One more thing to think about. Getting the laps on and off. There is not a great way to hold the lap disc while trying to tighten or loosen the nut. The offset of two circles works great to create a pinch point. I keep a 1" diameter dowel about 18" long next to mine and that gets inserted into the pinch points making it super easy to install and remove the plates. This top view diagram shows how it works on mine Chuck
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jamesp
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Post by jamesp on Mar 4, 2018 10:09:45 GMT -5
One more thing to think about. Getting the laps on and off. There is not a great way to hold the lap disc while trying to tighten or loosen the nut. The offset of two circles works great to create a pinch point. I keep a 1" diameter dowel about 18" long next to mine and that gets inserted into the pinch points making it super easy to install and remove the plates. This top view diagram shows how it works on mine Chuck So you have a 10 inch 'bowl' with an 8 inch lap plate. I will have a 14 inch bowl with 8 inch lap plate. But will offset the drive shaft about 2 inches from the center located drain. Making a similar pinch point. Interesting use of locking the disc with the dowels at pinch. I get it. I noticed the glass blower's 24 inch flat lap simply has a 1/8 inch tall raised pin that he uses to lay his abrasive disc on at center point. The friction of the backer plate to the abrasive disc is all that is used to keep them together. He uses mostly 12 inch abrasive discs on this 24 inch backing plate. Spinning about 300 to 400 RPM, so slow. That lap is about always being used in the "cold working" area as they call it. i.e. where the lapidary equipment is.
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NDK
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Post by NDK on Mar 4, 2018 11:13:02 GMT -5
I think that's a fantastic idea jamesp. Wasn't thinking you had room to offset the shaft.
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jamesp
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Post by jamesp on Mar 4, 2018 11:49:55 GMT -5
I think that's a fantastic idea jamesp. Wasn't thinking you had room to offset the shaft. Yep, 14 inch bowl/8 inch lap blade. May be a bit bulkier but the point where the work gets done is all that counts in the end I suppose. This is actually an easy to weld item, and with a welding jig they could be cranked out quickly. Parts are heavy duty yet cheap NDK. Let's see what a moron engineer/welder comes up with lol. Chuck and Tommy gave me all the photos needed to plagiarize their designs...
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NDK
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Post by NDK on Mar 4, 2018 11:59:05 GMT -5
Yup, I think you've got a winner of a design. Being heavy as you described earlier I think will be a big advantage. My lap is fairly heavy with direct drive off the motor & plywood body. I have screw on 3/4" rubber feet on it and it stays put. You'll like this machine when it's up & running.
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jamesp
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Member since October 2012
Posts: 36,392
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Post by jamesp on Mar 5, 2018 9:55:06 GMT -5
Yup, I think you've got a winner of a design. Being heavy as you described earlier I think will be a big advantage. My lap is fairly heavy with direct drive off the motor & plywood body. I have screw on 3/4" rubber feet on it and it stays put. You'll like this machine when it's up & running. I always had heavy industrial rock grinders for the most part. Looking forward to a machine that has some finesse. Hey, thanks for the suggestions and thoughts. I had been looking at making a lap out of those tank heads for a long time. Long been brain storming about this project. I would have preferred direct off the motor if it had variable speed. Using this mostly for glass so the diamonds should about last forever. One of it's main tasks will be removing a 1/4" of clear unwanted glass off the back of pendant sized pieces. That is simply mass material removal with the 60 grit plate 100 at a time. Mud maker.
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NRG
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Post by NRG on Mar 5, 2018 11:16:53 GMT -5
Curious why you aren't using your granite pads on grinder motors for this?
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jamesp
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Post by jamesp on Mar 5, 2018 19:40:49 GMT -5
Curious why you aren't using your granite pads on grinder motors for this? I guess the lapper spins slower and has big surface area. Mainly those 2 reasons. They do have bigger pads though.
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