Building/modifying An Atlas Th42

[great white]

Mounted the tach sensor for the rpm gauge today:



The magnet is a small neodymium dot. Hangs on to the spindle just fine all on it's own. Routed the wire through a rubber lined clamp to keep it out of the change gears and added a second clamp on the bottom of the guard for neatness if nothing else.

I used an old adapter (12v) from my junk drawer to power the tach. It turns on and off with the power bar, which turns everything else off too.

I popped the connector into the control/display head and powered it up.



Looked good, but I turned the lathe on and it stayed at "0". I did a bit of troubleshooting, but it wouldn't move off "0". I had a second head (bought for the drill press), so I plugged that in and it worked fine.

I turned them both over and inspected them with the 20X lighted magnifier. Yep, there it is: the first head is missing and OpAmp on the board. Looks like it was knocked off the PCB somehow, you can see where something used to be soldered to the pads. Shipping, birth defect or it happened on my shelf, I have no idea. It was also bought back in feb so any chance of returning it is long gone.

A stroll through ebay reveals it's as much for an op amp as it is for a new display since the chips had to be bought in quantities. Ditto for non eBay suppliers.

A quick rummage through the junk drawer again turned up a handful of opamps. Looking up the specs called for a Ic 8-16 mA OA on the pcb, but the closest I had was one spec'd for 50 mA. Well, it's just a diode and an emitter array, the display is useless like it is, so i figure what the heck: fire up the Weller wesd51 station and drop the 50 mA OA on the board. Do or die!



Out to the shop, plug it in and: bingo!

Works perfect.

So I'll put the "as delivered" one on the lathe and put the repaired one away for the drill press.

Quick vid of it up and running:

Seems to track fine and is plenty accurate for the type of work I'll be doing. Takes a second or two for it to refresh to zero once it stops, but that doesn't matter a wit to me since I'm done with working whatever is in the chuck at that point anyways. It will take longer for me to grab the mic and measure the work than for it to refresh to "0".

Decent bit of work for about an hour's worth of time. I'm quite happy with the results.

 

[great white]

Got a few spare moments tonight so I tried turning a bit of black pipe I had already mounted in the chuck.

I was actually able to dial in the right rpm for the proper sfm with the turn of the dial and the DC motor refused to bog like the old ac motor. All while running on the highest speed pulleys.

Cut fast and easy. Very nice change. Almost like a different lathe!

Still have some chatter, but I think that's down to my just starting out grinding my own tooling and the one I have in there right now has a rough/dull edge. I'll get that cleaned up this weekend and see if the chatter goes away or at least get to a decent finish on the cuts.

My little grinder doesn't have the best of wheels for making tooling (genetics coarse and fine wheels), so I'll probably try the sharpening stone once I get the rough grind done. Kinda back on familiar ground for me as I sharpen my chisels and knives on a hand stone all the time with good results.

Still, very pleased with how the DC motor project came out. Much more usable machine.

Now, where's that drill press.....

 

[schor]

What pulleys do you have setup in that video? What is maximum speed you can go?

 

[great white]

What pulleys do you have setup in that video? What is maximum speed you can go?

All oem, what came with the lathe.

Baldour motor is the same speed as the ac motor, 1750 rpm.

Haven't had it maxed out on speed yet. I'll check today. In theory, it should be capable of its rated 2072 rpm I guess....

 

[great white]

So. The lathe maxes out at just a touch over 1000 rpm.

Time for a bigger motor pulley.

It's a 2" right now, same size as the one on the AC motor. Likely chosen to keep the motor speed up as it was only a 1/8 hp motor.

I'll try a 3" and a 4.5" to see what I can get the rpm up to.

Those sizes mostly because I have them lying around right now.

Won't be exceeding the original 2072rpm rating though...

 

[wa5cab]

The two diameters on the original 10-428 (5/8" dia. shaft) and 9-428 (1/2" dia. shaft) were 4.390" (fast) and 1.930" (slow). For reference if you don't have the original 2-step countershaft pulley, the matching diameters were 7.5" and 9.0" or so one report said. So if you have the original countershaft pulley, a 4.5" motor pulley would put you only 2.5% faster than the speeds shown on the original speed chart.

Edit: That would be with the motor at 1740 RPM.

 

[great white]

So a 4.5" pulley will overspeed the lathe with the 9" countershaft pulley. Saw 2200 and didn't want to push it any higher.

No problems though as I just won't turn up the variable speed that high. It was pretty close to maxed out at 2200 anyways.

 

[wa5cab]

OK.

 

[atlas ten]

Mounted the tach sensor for the rpm gauge today:



The magnet is a small neodymium dot. Hangs on to the spindle just fine all on it's own. Routed the wire through a rubber lined clamp to keep it out of the change gears and added a second clamp on the bottom of the guard for neatness if nothing else.

Mounted the tach sensor for the rpm gauge today:



The magnet is a small neodymium dot. Hangs on to the spindle just fine all on it's own. Routed the wire through a rubber lined clamp to keep it out of the change gears and added a second clamp on the bottom of the guard for neatness if nothing else.

I used an old adapter (12v) from my junk drawer to power the tach. It turns on and off with the power bar, which turns everything else off too.

I popped the connector into the control/display head and powered it up.



Looked good, but I turned the lathe on and it stayed at "0". I did a bit of troubleshooting, but it wouldn't move off "0". I had a second head (bought for the drill press), so I plugged that in and it worked fine.

I turned them both over and inspected them with the 20X lighted magnifier. Yep, there it is: the first head is missing and OpAmp on the board. Looks like it was knocked off the PCB somehow, you can see where something used to be soldered to the pads. Shipping, birth defect or it happened on my shelf, I have no idea. It was also bought back in feb so any chance of returning it is long gone.

A stroll through ebay reveals it's as much for an op amp as it is for a new display since the chips had to be bought in quantities. Ditto for non eBay suppliers.

A quick rummage through the junk drawer again turned up a handful of opamps. Looking up the specs called for a Ic 8-16 mA OA on the pcb, but the closest I had was one spec'd for 50 mA. Well, it's just a diode and an emitter array, the display is useless like it is, so i figure what the heck: fire up the Weller wesd51 station and drop the 50 mA OA on the board. Do or die!



Out to the shop, plug it in and: bingo!

Works perfect.

So I'll put the "as delivered" one on the lathe and put the repaired one away for the drill press.

Quick vid of it up and running:

Seems to track fine and is plenty accurate for the type of work I'll be doing. Takes a second or two for it to refresh to zero once it stops, but that doesn't matter a wit to me since I'm done with working whatever is in the chuck at that point anyways. It will take longer for me to grab the mic and measure the work than for it to refresh to "0".

Decent bit of work for about an hour's worth of time. I'm quite happy with the results.

Hi. Have you had any clearance issues with the bigger gears and the sensor?
Jack

Sent from my SGH-I337M using Tapatalk

 

[great white]

not sure if there was a question there, forum won't let me expand your quote so all i can see is the picture in my original post.......