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rsr911
03-30-2005, 08:21 PM
http://24.172.209.26/618%20Micromaster.jpg


Went and bought a grinder for the company today, this is the one I'm gonna try to grind plastic with but mainly grind/polish SS and regular steel. It's a Brown and Sharp 618 Micromaster with hydraulic feed on at least the X, I won't know about the Y until I get it hooked up but I don't think it has it. The machine looks much nicer in person with the only problem I'm seeing being that the mag chuck is weak, but the lever is sloppy so I wonder if it's just not lifting the magnet enough. Anyway it's also got a nice coolant trougth, micrometer dials on the Y and Z, all the wheels and lever operate smoothly without slop. They where asking $2000, I got if for $1500 which was my max budget. I got the machine in place tonight and tommorrow I'll wire it in and see how it runs. http://bbs.homeshopmachinist.net//wink.gif

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-Christian D. Sokolowski

wierdscience
03-30-2005, 09:42 PM
Nice looking machine,did you get it from that dealer(name escapes me)in Cinncinati?I think that's where they are.

hoffman
03-30-2005, 09:47 PM
Very nice! Surface grinder is on my list...

rsr911
03-30-2005, 10:01 PM
Actually I got it from the dealer in Cleveland, HGR Industrial Surplus. It's hard to resist the urge to go down to work right now and wire it in! Now I just need to search around for a manual so I know how to maintain it properly.

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-Christian D. Sokolowski

rsr911
04-02-2005, 03:14 AM
Well,

Got her running tonight, had a scare when the hydraulics didn't work, turned out the pump was wired backwards (hmmm wonder if that's the reason it was for sale?).

Anyway the mag chuck is too weak to use so I'm going to take it apart tommorrow and see if the mechanism is messed up. The lever has a lot of slop in it and I can't help but think it's not lifting the magnet all the way up. Can one buy just a replacement magnet if need be?

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-Christian D. Sokolowski

lklb
04-02-2005, 06:53 AM
rsr911,
I was warned once not to take Mag Chucks apart.They told me you could ruin them. Maybe that's B.S. or an old wife's tale, but I would check it out with someone who knows about these things...............

...Ps beautiful machine...good luck.LK

JCHannum
04-02-2005, 08:21 AM
I get to HGR occasionally, it is a good thing I don't live closer. The grinder looks good. If it is a three phase, the pump may not have been wired backwards in the original location.

It is a bad idea to take a permanent magnetic chuck apart, as it can destroy the magnet. If it is weak or poor to begin with, you may make it better, so there may not be much to lose. Replacement magnets are not available.

The mag chuck won't be much use on plastic, aluminum and stainless anyway.

rsr911
04-02-2005, 11:06 AM
Well as far as the chuck is concerned I have nothing to lose at this point since it doesn't have enough strength for even light cuts. I was hoping to use doubleface tape on steel panels to hold the other materials to the chuck. Maybe I'll ruin it, maybe not but right now it's junk anyway. JC, I don't see how the pump could have been wired correctly in the original location. When I fisrt wired it up the machine I started it and checked spindle rotation which was correct. The pump motor is also 3 phase and after pulling 10 gallons of oil out of the sump I could see it bubbling out the input when I ran the machine, one qick wire swap later and the hydraulics worked fine. Today I'm going to remove the chuck and clamp down a piece of steel so I can check how well it grinds. After that I'll take a look at the chuck.

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-Christian D. Sokolowski

jkoper
04-02-2005, 12:23 PM
I have repaired a few mag chucks. Usualy the cam that lifts the magnet is worn as well as the pivot holes.Most of the time I make a new cam and bush the holes.

rsr911
04-02-2005, 03:25 PM
Today I took the chuck apart, it was supposed to be filled with 140W oil but was bone dry. It has regular ferrous magnets in it and they are rather weak. The cam was worn but the magnets aren't lifted, a metal plate slides back and forth. I'm pretty sure the magnets are just shot. I don't hold much hope for finding replacements but I'll check with the manufacturer as well as maybe mcmaster-carr. If not I'll look for a good deal on ebay. I knew the chuck was weak when I bought it and don't need it for my plastic project anyway but it would be nice to have a good one. Another thing I noticed is that the spindle motor seems week to me. It's only 1 HP but it doesn't take much to stall it. Fortunately I've got several 3ph 1hp motors lying around that I could install in it's place. Since I've never used one of these machines I really don't know how strong the motor should be but it seem like it's way too easy to bog down or stall the motor. My other option is to take the motor to a motor shop around the corner that we do business with and have them rebuild or at least test it. They usually give us a good deal on pricing.

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-Christian D. Sokolowski

Michael Az
04-02-2005, 07:27 PM
Nice grinder Christian, looks like my microgrinder that is manual feed. With the motor, one hp should be plenty of power, might be something wrong with the motor. Something to check out, these come with two drive systems. One is permanet lubed spindle ball bearings with the spindle belt driven with 6 o rings. The other spindle type is plain bearing, drip oil and the spindle is connected direct to the motor. If yours is the latter, you may want to stay with that motor and get it repaired because I'm sure that motor is balanced which might make a big difference in the finish with your grinding. If you have an outside oiler on the spindle, then you have the plain spindle direct drive type. The o ring drive has ball bearings on the spindle. I just put a new single phase motor on mine which is the o ring drive and getting a good finish so guess I got away with it.
Michael

rsr911
04-02-2005, 07:43 PM
Yep mine has the O-rings, the motor looks like a lot of others I've seen, nothing special. How deep can your's grind per pass? Seems like this one stalls at any more than about 0.005-0.010" with the table on slow feed. At high feed it stalls at less. I'm going to check my pallet of motors and see if I have a match. I'm also missing one O-ring, do you know where I can get one or a set?

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-Christian D. Sokolowski