docharber
has rocks in the head
Member since October 2008
Posts: 693
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Post by docharber on Apr 17, 2009 19:10:35 GMT -5
Does anyone know where I can find plans for a homemade 16-20" vibrating lap? I need something really simple that doesn't require welding or parts fabrication. thanks muchly!
mark H.
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Mudshark
fully equipped rock polisher
Diplomacy is the art of saying 'Nice doggie' until you can find a rock. Will Rogers
Member since December 2008
Posts: 1,083
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Post by Mudshark on Apr 18, 2009 7:49:10 GMT -5
Mark,I don't know of any plans for one but if I was going to make one I would just copy a store-bought unit.You might be able to make one without welding any parts but there will be some trial and error involved.Maybe use the base of a vibe tumbler but to go 16-20 inches you would need more support on the outside of the table.I think maybe a plywood box set around a vibe base with a stiff spring at each corner supporting the base might work.The plate would need to be flat and beefy so a bigger motor may be needed.The counter weight and springs would need to be just right to get good movement on the plate.I've been wanting to build one but other projects keep popping up and it's still on the back burner for now.Good luck with this and keep us posted on your progress. Mike
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docharber
has rocks in the head
Member since October 2008
Posts: 693
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Post by docharber on Apr 18, 2009 14:01:52 GMT -5
I live in a lapidary wastland in the Florida panhandle and don't have access to a machine to copy. I've been blown away bu y the sophistication of the "homemade" machines I've seen here. I have a friend in Texas who was involved in building the first Texas Lapidary flat laps many years ago (early 1970's) and he told me it's just a matter of using an eccentric cog to geneerate the vibration. But, he's not here. I get bogged down with what size shaft to use, what to use for the pan/plate, types of bearings, etc. Not to mention the fine tuning. I have an old 36" exercise trampoline that has given me some ideas, but that's as far as it's gotten. I have suitable motors. I have thought of making a very small flat lap with a stainless cake pan mounted on a plywood base and screwed down to my Raytech TV5 base. It has what I think is basically the same sort of action, though I think I need the vibes in a flatter plane. I thought of making the weight adjustable both up and down the shaft (down would flatten the vibrating plane) and use a screw mechanism to increase or decrease the rotating mass on one side of the cog to intensify the vibration. I understand I miderstand most vibe laps use a vertical shaft set in a bearing on the plate on one end, a fixed bearing on the other,, and having an eccentric weight on the shaft to generate vibration. I have some mechanical skills, and I'm builduing a new 20 lb. tumbler now- I just have to finish a few more coats of plastic coating material on the interior and it's ready. The Vibe, though, is a bigger challenge. I think I can use the textured polystyrene sheets used for fluorescent diffusers for mylap plates, cut to fit in the pan, which would have a generous coat of PlastiDIp or equivalent (I bought a can of bedliner at AutoZone for $13 that I think will work well, too). I could switch out the polystyrene plate with each grit change and rinse the pan out. If anyone has suggestions about the bearing mechanism, what makes a good plate, etc.- I'm all ears.
Mark H.
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Post by Jack ( Yorkshire) on Apr 19, 2009 1:19:35 GMT -5
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docharber
has rocks in the head
Member since October 2008
Posts: 693
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Post by docharber on Apr 19, 2009 16:32:53 GMT -5
I appreciate the help, Jack- but I'm wanting to build a vibrating lap to polish flats. I've decided to just buy an 8" Ameritool flat grinding lap from John at JS Gems as the package includes lots of extras that would cost me way more if I bought them after the fact for my homemade machine. The base unit is pretty inexpensive as lapidary machines go (Ameritool) I have enough experience trrying to build my own stuff to realize it can cost a great deal to save money, and you don't have a warranty or spare parts easily accessible. I did see the plans for a 45 degree open tumbler and got some new ideas from that. i still have my own 1 cu ft. machine in the garage waiting for me to finish the interior plastic/vinyl coating. Mayvbe within the month it will be uop and running. i think it should hold 20 lbs or so. modeled it after the thumbler's with 8 flat sides 9.5" between end plates which were trimmed down a bit from 14" flat wooden disks, one with a 4" hole with a PVC pipe insert and a test plug to seal. I may end up putting an opening in the other end, too. That will be tumbler number 5. , 4 rotary and 1 raytech TV5. All I need is a good slab saw and I'm set.
Thanks again, Mark H.
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