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The $100 Micromaster is ALIVE! Cross feed problem though...

eKretz

Diamond; Mod Squad
Joined
Mar 27, 2005
Location
Northwest Indiana, USA
So finally got the $100 B&S MM Series II up and running. It grinds pretty darn well. Everything seems to be functioning as it's supposed to, all auto functions are working. The stepper is controlling the head elevation beautifully; can easily bump tenths and it doesn't drop, rock solid. I got a start on grinding the mag chuck today but didn't get it finished. Ran out of time.

The only issue I've noticed is that the cross feed seems a little wonky. When set for 3/16" sometimes it will feed 3/16" and sometimes a lot less... Unless it's my imagination, seems to happen more frequently near the ends of table cross travel. Any of you fellas had this issue and fixed it? The ops and maintenance manual give a couple things to check, I'll be delving into those ASAP.

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Can't offer any help on this, just wanted to congratulate you for getting it up and running. Didn't know you had this, nor that purchase price was below retail.
 
Thank you. It was a very lucky find. Previous owner was an automation company that sidelined it when they got a larger machine. They listed it for sale at a price way higher than I could ever afford, but when I saw all the buttons from the "Dial-A-Size" option I was curious about it, so I asked about it hoping to get some info just out of curiosity. The guy replied and told me how it worked and that was that.

A few weeks later he emailed me and said that the machine needed to go as they were moving to another building and the owner didn't want to bring the machine with as it was surplus and sat unused. They were moving out at the end of the week... If I wanted it and could come get it immediately I could have it for $100. Needless to say I showed up the next morning with a trailer!
 
Interesting machine with no down hand-wheel...Let us know how the Dial a size works..Never ran a micromaster with having that.
Good find for $100

Back in the day I practiced a dial a size hand operation by having a height set diamond..so perhaps a .00055 down feed from the dress would make size regard less of all other aspects of the grind, yes it was subject to diamond wear but that was a very small amount of size.
Nowadays CNC grinder I have run use a probe to check wheel and part...makes everything too easy...Darn.. No cance to brag any more... when its the machine tha makes size.
 
I have only tried it out with an empty table so far. It did what it was supposed to though. All the head controls are electronic and controlled by a stepper motor. You can rapid up and down, slow advance down, and step down in any ten-thousandth increment from . 0001" to .0099" per button press in manual mode.

This machine has a Dress/Compensate feature also, so if you need to dress the wheel in the middle of grinding, you can keep track of how much you dress off using the readout, then set that number into a dial and press the Compensate button and the machine moves the head down that amount without changing the readout.
 
Ah geez. I was rough grinding the mag chuck in, running at 3600 RPM, kept getting burn marks. Wheel is a 46H... I was like WTF?! Took the wheel off again to make sure I didn't misread the hardness...turns out it is an 8" wheel, not a 7". Doh! Rookie mistake. Dropped RPM down to 2800 and all is right with the world again.

Good news on the spindle too; while I had the wheel off I dropped an indicator on the adapter O.D. and face. Less than . 0002" runout on both. Barely any deflection with a hefty shove from me either.
 
First part today, octagonal shape ground on 60Rc D-2 @ 3.3755" across the flats.

Really gotta get after that cross feed issue, it's costing a lot of time.
 

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Started digging into the guts of the machine today. I checked the head gibs, they were perfect. Pressure lube sure helps keep a machine in good shape, doubt they were ever touched by anyone - the caps over the adjustment screws were painted over and the paint came off with the caps.

Next I checked the high and low pressure relief valve set pressures. High is spec'd at 120 psi and low at 5-6 psi. High was spiking a 150 psi gauge pretty hard - must have been close to 200... Backed that down to 120 and the table throttle works much better now. Low was sitting at 15 psi, dropped that back to 7 psi. Next will be digging into the cross feed valve block. If I don't find anything there I'll check the cross feed cylinder seals.
 
They are never below the surface. There's no need for them to be. Brass is nonmagnetic. They are only there to act as a separator between the steel segments.
 
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They are never below the surface. There's no need for them to be. Brass is nonmagnetic. They are only there to act as a separator been the steel segments.

In the old ,old days guys would hand scrape the lead, or brass thinking that might give better holding. Some thought it would cause less loading of the wheel so less chance to burn a chuck...Nobody I know nowadays does that .. *Using the correct wheel is enought to avoid burning and the scraped low place just made it harder to clean your chuck.

My first grinding job and with all pro grinder hands all the surface grinder chucks were that way. Most hand Reid 6-18s A big G&L 10-36, bunch of Blanchards, few bridgeports, a broacing machine, few drill presses, couple of saws, TCT welding machine..sand blaster...what else..?

A hand squeege makes a good chuck cleaner when using coolant...with care to not bump hand.
 
Yep, I've never bothered relieving the separators. A light dusting cut on the finish grind of the chuck with an open free-cutting wheel dress and loading isn't a problem. If someone tried to grind .005"+ off the chuck then I could see brass loading being a problem.

I use a squeegee also. First I shut off the magnet, then hose off everything with the coolant as well as possible. Then the squeegee, then rag, then hand. Light dusting with flat hone to look for any dings or high spots, then reclean with acetone and lint free paper towel, then hand wipe. Remount work. Didn't have to deal with that on the octagonal job though, had that in a spin-dex.
 
As far as holding better, after the chuck was ground in I set the dresser on top and turned the magnet on, then tried my darndest to move it. It didn't budge at all with all the force that my 210 pounds could muster. I don't think I could ask for any better holding.
 
I like to use a big hone fine side but little honing. Qt: {reclean with acetone and lint free paper towel} never did the acetone thing.

For some jobs down grinding can save time. Eliminating much if not all cross feed incremental cross feeding. You might have a wheel wider than the grind or half as wide. You full wheel down feed on the part to size with no cross feed steeping at all. Just down feeds and long travel. Some jobs that have multiple facets or multiple number of the same part one might set the diamond to the wheel at finishing height and dress with intention that .0005 from that dress will make size. The down fee amount depends on the material, spindle HP and the wheel in use. Often you can increase until you notice some lowering in the RPM.
Yes you have to pay more attention to where the wheel will lose size
 
Yeah I should have thought about that actually since I was having trouble with the cross feed... Would have probably saved me some time and aggravation.

I ended up whacking down .001" at each end of the crossfeed on reversal. Roughed down to +.001" and gave the wheel a dress, then finished the flat. Indexed to the next one and used the fresh dressed wheel to rip down to +.001" again, et cetera. Usually ended up losing about .0005" - .001" off the wheel during roughing passes. That cross slowing down cost a lot of time though. Ripping straight down then moving over and doing it again would have saved me considerable time.
 
One day you run out fun things to do wet full wheel bottom grind across a part and vary down feeds from strating with .0002 and try to go to .002 per pass and see how you grinder pulls that load.
Make 5 passes at each down grind amount to feel how it pulls each load...

Then try a heavy down grind but only down feed on the grind side with a slower ling travel and free pass back on the climb side.

*Yes, block-in at the go side...yes use my two hands on for a little more tight.

Q: Do you have the 2 hp direct drive spindle?
 








 
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