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Author Topic: New to Lapidary & Gifted a Grinder/Polisher  (Read 1196 times)

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bob21801

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New to Lapidary & Gifted a Grinder/Polisher
« on: January 26, 2018, 07:10:50 PM »

My first post. I've only tumbled stones a few times, but have wanted to get into lapidary for a couple years, along with my several other hobbies. I started looking at Grinder/Polishers for making cabs several weeks ago, first considering a Hi-tech flat lap or slant machine, but even those seemed a bit steep for just giving this new hobby a try. I finally decided to make my own flat lap machine and picked up a used 1/3 hp motor on eBay, only to run into something unexpected a few days later. I work in a steel mill, and was talking with one of our QA guys. I knew they had a polisher/grinder in our lab. They'd been using an industrial Buehler Ecomet III Grinder/Polisher to prepare the steel for some testing, and I learned they recently upgraded to a newer model. This older model was put in our loft with no intention of it ever being used again. It's a variable speed, 50 - 500 rpm, and weighs a ton (probably about 100 lbs.) I talked to my boss and asked about the possibility of getting it cheap. He told me to just take it! I've looked this machine up online tonight and see used ones selling between $1250 and $2500. I believe I died and went to cab-making heaven, but wanted to check with you experienced lapidaries and see what you think, as I haven't seen this brand of machine mentioned in any lapidary websites or YouTube videos. Here's a link to the machine.

http://www.used-line.com/semiconductor-and-pcb/grinders-polishers-lappers-cmp/buehler-ecomet-iii/item-11477347

I appreciate any feedback.

Thanks,
Bob
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lithicbeads

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Re: New to Lapidary & Gifted a Grinder/Polisher
« Reply #1 on: January 26, 2018, 08:31:15 PM »

Welcome. Looks great to me. Flat diamond  pads work well but are not nearly as aggressive as silicon carbide. Flat diamond pads can be used with or without  the standard rubber backing pad. The pad underneath the pad gives a little drape so that the pad can conform to the stone a bit , a great help. When you get it I would love to see some pictures of the machine especially how the laps are changed. Your first instinct to build a macine is very good, not enough of that lately.Just enough water to keep the pad wet so the stone does not hydroplane. You will need a hard diamond lap as well for rough grinding. Have fun.
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Slabbercabber

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Re: New to Lapidary & Gifted a Grinder/Polisher
« Reply #2 on: January 27, 2018, 06:02:12 AM »

I thought about using our old Beuler at one time but the amount of work it would take to convert it to lapidary was just more than it was worth.  This machine is meant for polishing metal to very high tolerance.  The laps are inappropriate for stones.  The work surface is too small and the system is not made to accommodate the sough from grinding stone.  I would sell it and use the money to make or buy something more appropriate.
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vitzitziltecpatl

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Re: New to Lapidary & Gifted a Grinder/Polisher
« Reply #3 on: January 27, 2018, 06:55:51 AM »

I think Slabbercabber has the right idea. If you sell that one at the low end of the range you could get a used machine designed for what you want to do.

Trust me, it would be worth it to have a six-wheel setup if you want to see how much fun this can be.

bob21801

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Re: New to Lapidary & Gifted a Grinder/Polisher
« Reply #4 on: January 27, 2018, 09:14:40 AM »

Thanks a lot for the input so far. I'm really grateful for it all. I definitely have more to consider than I thought. I don't have the machine in my possession yet. I'll get it later today or tomorrow. No doubt, I'll clean it up and play with it a bit to get a better idea what I might do as far as using it or not. I know I have a LOT to learn, but I also know I'll enjoy gaining experience and knowledge along the way.

I've watched quite a few videos on YouTube, and have seen what appears to me as nice cabs, produced with a variety of machines, including homemade ones. I thought I understood that diamond wheels and discs were always better than silicon carbide, if for no other reason, than that they last longer. But wanting to start out without spending a small fortune, I ordered some good quality wet/dry silicon carbide sandpaper of various grits from an eBay seller. I believe they have a strong backing and will not tear easily. They haven't arrived yet. I figured I'd attach them to a homemade backing plate, on the homemade flat grinder/polisher I intended to make before I was given the Buehler. Again, I'm sure I have a lot to learn, but that's part of the fun, and I also keep thinking about what someone said - people have been grinding and polishing stones for thousands of years - long before we had fancy (and very expensive) multi-wheel machines designed for the task.

If the Buehler really isn't a good choice, maybe I'll do as suggested and sell it. If I sell it, I'm still not likely to rush right out and spend $1000 or more for a fancy machine for a brand new hobby. I'd be more apt to make my own flat cabber first, play with it for a while to see if I enjoy it enough to invest more heavily in the hobby. I do LOVE learning hands-on skills like this and plan to continue, but time will tell.  Even if I keep the Buehler, and or buy something different, I'll likely want to make my own at some point anyway.

The laps are inappropriate for stones.  The work surface is too small and the system is not made to accommodate the sough from grinding stone. 

Slabbercabber, I'm wondering if you could go into some more detail regarding the quote above. Pardon my ignorance, but when you say the laps are inappropriate for stones", are we talking about the sanding/grinding disks that are normally used on this machine? If so, couldn't I just use/fashion discs that are more appropriate? Also, the working surface on this machine is 8". Isn't that enough for a hobbyist to at least get working? I appreciate any more detail you could provide about what would be needed to make it worthwhile for my use. No doubt you have more knowledge in this than me, but in my mind, it can turn a surface at an appropriate speed and can supply a water drip, so doesn't it cover the basic needs easily? Again, thanks if you can elaborate.

I appreciate all the responses. Please keep them coming.

Bob
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Slabbercabber

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Re: New to Lapidary & Gifted a Grinder/Polisher
« Reply #5 on: January 27, 2018, 09:29:13 AM »

The machine in the photo is quite different from the one I've used.  If the surface is open as it appears, then it is big enough.  Notice though that there is no way to collect slough that is thrown off.  The laps are made to provide a perfectly flat mirror surface.  That will likely work for the last step but you would need coarser laps for all other steps.  I doubt you could buy them for that machine but they could be made by attaching sandpaper to existing discs.
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bob21801

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Re: New to Lapidary & Gifted a Grinder/Polisher
« Reply #6 on: January 27, 2018, 09:45:51 AM »

The machine in the photo is quite different from the one I've used.  If the surface is open as it appears, then it is big enough.  Notice though that there is no way to collect slough that is thrown off.  The laps are made to provide a perfectly flat mirror surface.  That will likely work for the last step but you would need coarser laps for all other steps.  I doubt you could buy them for that machine but they could be made by attaching sandpaper to existing discs.

Slabcabber, thanks so much for the quick response. I really appreciate the heads-up on issues I may face when trying to use this machine.

The picture shows a cover over the disc. If the cover was off you'd see an open space around the disc, about 3/4" I believe, where the slough would collect. The machine also has a drain in the back (probably 5/8" or 3/4"), so I THINK it will allow the slough to be drained away without issue. I'll post a pic or 2 of my own after I have the machine and get it cleaned up a bit.

The company I work at has various grit laps for these machines. Our QA lab uses something like 180, 320 and 600. They have an adhesive backing to attach to the disc. I'm pretty sure I can buy 1200# and others from the company or cut my own, and attach with spray-on adhesive or another way. I'm also mulling over ideas to make a cushioned leather faced disc for polishing on this machine, or possibly for the grinder motor I bought on eBay.  It's 1/3 hp, 1725 rpm, smooth and quiet..

I think this is going to be fun! Thanks again.  :thumbsup:

ETA - Oh no! One thing I just realized. The variable speed on this machine is 50 - 500 rpm. I believe 1725 rpm is typical for grinding/polishing stone. I imagine this is a BIG issue when considering the use of this machine. Comments?
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lithicbeads

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Re: New to Lapidary & Gifted a Grinder/Polisher
« Reply #7 on: January 27, 2018, 06:50:20 PM »

Variable speed is a bonus as high speed is often not the best . You will have fun figuring out what works for you as well as what suits you.
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Jhon P

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Re: New to Lapidary & Gifted a Grinder/Polisher
« Reply #8 on: January 28, 2018, 06:42:35 AM »

It will work fine, just learn to use it. 8” disc’s are readily available from online lapidary supply companies
Like Kingsley north. I assume that it takes stick on discs? Or dose it take magnetic ones? I don’t know if magnetic one come in 8”.
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vitzitziltecpatl

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Re: New to Lapidary & Gifted a Grinder/Polisher
« Reply #9 on: January 28, 2018, 07:14:13 AM »

Variable speed is a bonus as high speed is often not the best . You will have fun figuring out what works for you as well as what suits you.

Lithicbeads is quite right about the variable speeds. The high torque of that unit will be a plus, too. My first unit was a variable speed flat lap, and it only ran at high rpm for matrix removal and rough shaping.

Set the unit up in a large shallow pan of some sort, with a spray shield far enough away on the sides to allow for working room and any mess will be contained. As Jhon said, it will work.

bob21801

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Re: New to Lapidary & Gifted a Grinder/Polisher
« Reply #10 on: January 28, 2018, 09:18:51 AM »

Man, that thing was heavy, carrying it down from the loft, but it's home now. I was concerned the 500 rpm max would be much too slow, but if you guys say it's ok, I'm happy to hear it. I just started cleaning it up. It's pretty nasty. Now that I see it in more light, I realized it has a felt pad held on by a metal ring. Took a little prying the get the retainer ring off, with the dried on polish. The plate underneath is not magnetic, so I suppose adhesive discs are in order, and the retainer ring will also hold the edges securely. I turned it on and it seems to work fine. I can't wait to start playing with it. Lithicbeads, thanks for the suggestions about controlling the spray. There's a lip an inch away from the disc, where I can probably attach a spray shield of some kind. The room I think I'll use it in doesn't have a water source, so I may just use a small bucket with an aquarium pump. I'll figure something out for the drain too.

I also got a Buehler Handimet II Roll Grinder in the deal, with plenty on the rolls. http://inspecglobal.com/Buehler_HandimetII_Roll_Grinder.html

I'm not sure exactly how I'll use it, but I imagine it will also come in Handy. Thoughts on this?

Bob
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lithicbeads

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Re: New to Lapidary & Gifted a Grinder/Polisher
« Reply #11 on: January 28, 2018, 01:11:14 PM »

You just need a slow drip of water. A plastic bucket with a hole near the bottom and a valve glued in works great. You use aquarium tubing to get the water to the machine. cheap , simple and adequate. You may be surprised at how little water you need. I often just use a spray bottle on my flat laps if I am only going to use them for a limited time. Hydroplaning from an excess of water  slows things greatly during the sanding stages.
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bob21801

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Re: New to Lapidary & Gifted a Grinder/Polisher
« Reply #12 on: January 28, 2018, 06:35:25 PM »

I got it cleaned up and, of course, had to play with it a bit. I did one small piece of petrified wood freehand. I didn't shoot for perfection, just worked it a bit with 4 different grits an and polished it with the felt that came with it and a little TXP. It did the job. I plan to cut a 8" circle of rubber I have, probably 1/8' think, to try under the finer sandpaper, to see how that does. I'll also make a leather polishing pad. I have plenty of leather, as that's another one of my hobbies. (I need to get back to that.) I used some cheap silicon carbide sandpaper, cut to 9' and draped it over and fastened it down to the aluminum disc with the metal ring that was holding the felt when I got it. (no adhesive). I order some much better quality sandpaper a few days ago, and that should be here soon. I used a squeeze bottle of water to moisten the sandpaper, and I think that'll work fine until I come up with something better. All in all, I'm thrilled to get started. I have some stone and quite a bit of petrified wood, but I think most of it is probably more suited for tumbling. I have a very cheap tile saw to also help get me started, so I'll go with that for now, but I think I'll also order some slabs to give me more to play with. I read somewhere in the forum that someone here has some slab assortments to sell. I'll likely order that. This afternoon, I also made my first coin ring, after watching some videos last night. It came out ok for a first try. That was fun too. I'll give it to one of my grandkids.
Thanks again for all ter input. This newbie definitey appreciates it.

Bob
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Jhon P

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Re: New to Lapidary & Gifted a Grinder/Polisher
« Reply #13 on: January 29, 2018, 07:03:45 AM »

Hey Bob, how did you make the coin ring? Mandrel and nylon hammer
I play around with coin rings a little. You can get a few $ invested in all of the tools. There is a Facebook group that is helpful, they are more than willing to help with questions. Here is a picture of a couple I have done
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bob21801

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Re: New to Lapidary & Gifted a Grinder/Polisher
« Reply #14 on: January 30, 2018, 03:27:23 PM »

Hey Jhon P,
Sorry for not replying sooner. I picked up a terrible cold or flu a couple days ago, and have been trying to rest. I just started playing with the coin rings and have only made a couple - neither of them as nice looking as yours, but I'm watching a lot of YouTube videos and I know I'll improve with time and practice. I did use a nylon mallet and a cheap ring mandrel I picked up at Hobby Lobby. I also just bought a doming block set and punches from Harbor Freight - again trying to not go overboard buying tools until I learn more about making these rings. I have seen lots of tools used and offered on YouTube - no doubt a person could spend a small fortune getting started if he wanted to. I did order a better ring mandrel on eBay, with the sizing rings. It'll be early next week before it arrives. I also have my eye on a ring stretcher, but not quite ready to buy yet. Do you recommend one of those? I don't want to jump too soon and make  wrong decision. I don't do Facebook, so I'll probably ask questions here in the forum, as I need to.

Again, sorry about he slow response. Thanks your comments.
Bob  :coffee1:
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