Poor man’s Accufinish carbide lapping machine

[Latinrascalrg1]

It worked as it came as shown in the pictures or did you need to swap the wires?

 

[Janderso]

Where we going, where we going? Are we there yet? Huh? How much longer?

Be safe.

I started it, I should explain.
Ulma Doc, Bemnychree , Bob Korves, winegrower, eeler1, Dudemanrod, Aaron-w a, and others yours truly are members of a Sacramento Valley Hobby Machinists group.
We get together once a month.

 

[Janderso]

It worked as it came as shown in the pictures or did you need to swap the wires?

It worked right out of the box.
Unfortunately the rpm is too slow.
The advertised full speed was 450. It probably turns at 200.
I think it will work. I’m not thrilled. It was cheap.

 

[Ulma Doctor]

200 rpm might be a bit slow, but it shouldn't hurt.
it may take a bit longer to grind your scraper blades, but no big deal really.
with a 4" wheel you will still get 209 SFM
with a 6" wheel you'll get 314 SFM

did you get your 75% concentration diamond wheel already???

 

[Janderso]

Not sure what I got. I ordered them off flea bay. I'll let you know when they arrive.
I need to make some plans, make some parts and see where it goes.

 

[Latinrascalrg1]

It worked right out of the box.
Unfortunately the rpm is too slow.
The advertised full speed was 450. It probably turns at 200.
I think it will work. I’m not thrilled. It was cheap.

Is it possible the reason it may not be running at the higher speed is due to the wiring not being Exactly correct? I was really looking at those symbols and my interpretation is there seems to be 3 different dialects represented on the tag coming from the controler the 1st in red, 2nd the center section of the smaller grouped symbols, 3rd the larger Black symbols which seem to be the same as the motor symbols which is what i believe would operate the motor at the higher speed you where wanting.

 

[homebrewed]

I made something like that too. By intent it turns pretty slowly, around 120 RPM to avoid overheating hardened steel. If needed, I can place a water basin under the lapping disk to keep the disk from loading up, and also provide additional cooling if needed (higher RPMs tend to sling lubricant around too much, another reason for 120RPMs). It uses a stepper + driver and simple 555 timer-based oscillator to pulse the "step" input to the driver.



The above photo shows the lapping wheel, which in this case has been charged with 3,000 grit diamond powder (the other side of it is 150-grit diamond, which turned out to be far too coarse for anything I wanted to do). The tool holder, along with a carbide scraper, are sitting on top of the tool support.



Above is a closeup of the tool holder. The blocks on the top and bottom clamp the scraper in place. The left side of the holder has replaceable brass inserts with different radii -- a larger radius is used to shape and sharpen larger scrapers. In use the brass is pushed against a stop on the end of the support bracket so it's easy to get a consistent radius along the entire cutting edge of the scraper. The back end of the aluminum support rests on an all-thread "riser" that is used to set the bevel angle of the scraper. IIRC, I chose -8 degrees for my scrapers. Right now that's not feeling aggressive enough -- but I'm trying to scrape something that is pretty hard. Easy to change if need be.

I don't use any lube when honing with the 3,000 grit wheel. I get a mirror finish with it. I have 14,000 grit diamond powder, but that would be massive overkill.

I had just about all the parts for this in my junk box. The stepper and driver came from my as-yet-incompleted CNC upgrade to my mini mill. I made the arbor for the lapping wheel on my mini lathe.

I've got 150, 300, 600, 1200 and 3000 grit lapping wheels, purchased from an ebay lapidary supply company.

The base and stepper supports are made of scrap plywood. I DID buy the angle brackets to attach the vertical piece to the base.

 

[Janderso]

Is it possible the reason it may not be running at the higher speed is due to the wiring not being Exactly correct? I was really looking at those symbols and my interpretation is there seems to be 3 different dialects represented on the tag coming from the controler the 1st in red, 2nd the center section of the smaller grouped symbols, 3rd the larger Black symbols which seem to be the same as the motor symbols which is what i believe would operate the motor at the higher speed you where wanting.

Interesting, I’ll take a closer look.
Thank you.

 

[Janderso]

Latinrascal,
Could you give an example of which wires you would move/line up to achieve a higher speed?

 

[Latinrascalrg1]

Ok this is what I THINK is the correct pattern (assuming the wires are in the correct corresponding position)
From the picture the wires dont Exactly "line up" with the dipictions so make sure you count the spaces. Also, I would use the controler connector to swap the pins on because the controller has the correct wire schematic with color code, unlike the motor side! This will make it easier to remember which symbol goes to which colored wire
All but the Blue wire symbol have identical matches...the blue is very very similar if you look closely (maybe Chinese shorthand/slang!) So this is what "I" would try but if you do you do at your own risk because I don't speak any of the Chinese dialects!

So it looks like the green and white are in the correct spots and you would need to swapp the yellow and black, then swap the blue and red (in the controler connector side)

Also on the motor side connector im guessing (which Now kinda makes me think those stickers may have nothing to do with each other in relations to other then fitting together) the thicker white and blue and yellow wires are the main winding power and the 2 thinner blue wires are the controller inputs. If that so then according to the big schematic that shows where the wires come out of the motor the thicker wires would connect to the white, red and black wires as they came out of the box only maybe in a different order!