Brown & Sharpe 2l Surface Grinder -- Sparks!

Bob Korves

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Rest In Peace
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Continued from http://www.hobby-machinist.com/thre...face-grinder-getting-close.49978/#post-420525

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The grinder is completely together and running well. Made my first sparks yesterday. I have been gradually breaking in the spindle, starting off with the spindle mounted on a cobbled together rig that I did not have enough guts to take photos of, would have never lived down the Rube Goldberg title if I showed it... It only took about 20 minutes to build it, worked just fine, and that let me test the spindle apart from all the other systems that would have also been untested. If there is anything I have learned over the years, it is to only test one unproven system at a time, with the rest tried and true wherever possible. Too many variables otherwise. The spindle was also known to have locked up and failed in the past.

After about eight hours of bench testing the spindle at about 2000 rpm (factory is 3200 rpm), and it did get quite warm at first, I installed it on the machine, mounted the new drive belt, and started off with the VFD set at 25 Hz, ran it for several hours, kicked it up 5 Hz for ten minutes, turned it off, and started the next session at the new and higher speed. Lather, rinse, repeat. Today I reached 60 Hz, full speed, everything still going well, spindle running cool, no noise or vibration. The table longitudinal feed and cross feed are both working.

I ground a piece of hardened tool steel mounted in my grinding vise (the mag chuck still needs to be addressed.) The patch I ground is only about .5 x 1.25". I only took two passes, one .001", the other .0003". It has a nice surface finish, especially for using an old white 60 H wheel that was worn down to about 5" O.D., not completely dressed and running at 40 Hz. It did have a little bit of faint washboard grooves in the across the table direction, probably from being out of balance from not being dressed completely. But It did make sparks, which is what grinders do. Yippee!

Now I need to stop the testing and address a few issues. One idler pulley has bearing issues and needs to come apart. The automatic cross feed system is not always kicking out when it should. The plunger that the dogs push down on to trip the feed lever works fine when the carriage is moving relatively fast, but hangs up on gentle cross feeds, actually lifting the carriage and table over the plunger with the dog. The mechanism feels fine, but it will need to come apart to see what is going on in there. At least it is an external, bolt on unit. The leather feed belt has come off the pulleys twice, both times when the table feed was malfunctioning, but still it seems a bit loose, too easy to get back on, so it probably needs to be shortened half an inch or so.

The VFD is in its added enclosure box, which has a second fan and an air intake filter, but I am also going to take the display/keypad off it and mount it on the enclosure box cover. It is easily removed from the factory cover and has a tape harness from the VFD circuit board to the display/keypad. I also want to add a potentiometer for motor speed and an added motor on/off switch. Those Asian VFD's are not known for having robust key pads.

The machine is very close to being ready to put into service, not much to worry over at this point. It's pretty much all over but the smiling!
 
Really looks nice Bob. Sounds like you're getting it dialed in.

Ted
 
looking good Bob, glad to hear that you only have some minor issues to clear up!
Congratulations!!!:D
 
THE MACHINE DEFINITLY FOUND THE RIGHT (NEW) HOME!
Thanks, John! Without your help on this it would have been a much more difficult project. It is really refreshing to see someone who cares what happens down the road to the machines he sells. I think you also care about your old machines like they are your children...
 
Thanks, John! Without your help on this it would have been a much more difficult project. It is really refreshing to see someone who cares what happens down the road to the machines he sells. I think you also care about your old machines like they are your children...
Guilty as charged --- I have been through a lot of machinery on my journey to retirement, and (obviously) have continued on that (oily) path. I'd like to think that I have consistently "traded up", but not always ---- certainly in this case, it is true; I have owned two of the B&S 2l surface grinders, I do like them, but the B&S micromaster really shines!
 
You may have a line of about half dozen guys with projects on Oct. 1st :)

Ted
Bring 'em on! However, there are more repairs, tooling acquisition and reconditioning, and self taught training classes still to come. Baby steps. That line of scruffy machinists at the shop door might stay a bit long for a while. "Warning! Steep learning curve ahead! Use low gear!" Don't bring anything you really care about being perfect for a while...
 
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