ELS Conversion on Weiss 1127

WobblyHand said:
... First thing is to come up with a proximity switch that can be the emergency stop. This switch needs to be very repeatable to within a few thousandths. I think there are some that will do this, but I don't know if they are small enough for our sized lathes. The ones I have seen are fairly long.
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I have 'snap action style' switches on two mills for use as homing switches. Not this exact brand, but the snap acting types are all very similar. The first set was supplied by the manufacturer, the second set I chose for a build because they work so well. Basically, I'm seeing repeatability to a tenths or so. I could get exact part numbers from the switches later, if you are interested.


There are different plunger options. If they were mounted with the plunger perpendicular to the travel, and you used a ramp or cam to activate it (so over travel wouldn't damage the switch) I think they'd be just fine for this application.

Reading this thread makes me want to get started the ELS for the lathe here too! :)


Dan
 
dkemppai said:
I have 'snap action style' switches on two mills for use as homing switches. Not this exact brand, but the snap acting types are all very similar. The first set was supplied by the manufacturer, the second set I chose for a build because they work so well. Basically, I'm seeing repeatability to a tenths or so. I could get exact part numbers from the switches later, if you are interested.


There are different plunger options. If they were mounted with the plunger perpendicular to the travel, and you used a ramp or cam to activate it (so over travel wouldn't damage the switch) I think they'd be just fine for this application.

Reading this thread makes me want to get started the ELS for the lathe here too! :)


Dan
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Thanks for the link. Got my order in from Digikey today, but I just read this post. Maybe next order... I really want to integrate the ELS with my VFD, but that may take some creativity, or a newer, better and more capable VFD. Poring through the VFD manual, and I have yet to figure out if I can enable an auxiliary e-stop.

There's some options these days for ELS systems. I'm kind of partial to mine though :grin: Will be adding some better DRO's to my lathe. They have been ordered, but haven't quite left the mother country. Soon I hope. Then the adventure of fitting them onto the platform begins. I *think* they will fit. I do love having the DRO's integrated with the controller.

Hope to be able to add some more sophisticated helper functions, but want to keep the overall system simple to use. Adding functions isn't too hard, but keeping it easy to enter information and having the steps be intuitive, that takes more thought, and a bit of testing.
 
My 1um scales arrived and are undamaged. Using the 1um test mode I could see that they were at least close to 1um and a rough 3" was about 3 inches. Found a bug in my serial output in this test mode though, will need to fix that.
 
WobblyHand said:
My 1um scales arrived and are undamaged. Using the 1um test mode I could see that they were at least close to 1um and a rough 3" was about 3 inches. Found a bug in my serial output in this test mode though, will need to fix that.
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What brand of scales did you end up with? Anything in particular, or just import asian ebay stuff?
 
dkemppai said:
What brand of scales did you end up with? Anything in particular, or just import asian ebay stuff?
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I purchased from AliExpress, so I could cut out the middle man. Disadvantage is returns can be an issue. Advantage is price. I believe I purchased from Hymmsann, not sure about spelling. They seemed to have a "store" and it was dedicated to DRO's. Seemed non-sketchy, at least. Box was well packaged and survived the trip to the US. Even UPS didn't muck it up. The complete scales with housings, chip guard, read head and brackets were $65 each. Need to test them for dead zones, but seem to be working fine.
 
I purchased Sino brand scales from the same seller as WobblyHand - HYMSEANN. Shipping was not quick and the read head came damaged so i contacted the seller hasn't done much any other than message about it. Overall it was an OK experience - i wouldn't call it excellent though. The price was cheap though - $75 for the Z axis and $120 for the slim scale for the X axis. I was disappointed in that i didn't read carefully enough and the X axis was 5um instead of 1um.

I purchased a magnetic X axis 1um linear encoder from here:
www.aikrondro.com

magnetic encoder SLIM type | AIKRON DRO

AIKRON slim type magnetic linear encoder is suitable for arrow space installation,it works really good on lathe x axis.
www.aikrondro.com www.aikrondro.com

The shipping was $40 but it arrived within a week instead of a bit more than a month. I haven't had a chance to mount it to the lathe but the quality seems good and the low profile of the magnetic scale i hope will be advantageous.
 
It's been about a month since i had some time down in the shed - work has been slammed.

The new stepper motor pulleys arrived today. I installed the 24T pulley on the stepper motor to drive the gearbox 2 stepper revolutions per 1 gearbox revolution. I was able to modify the ELS to drive the stepper motor twice as fast with the new pulley ratio so it's the same as before. I spent some time testing and double checking that the threading was correct.

While the torque curve shows that the stepper motor loses torque as you spin it faster the 2:1 torque you get from the pulleys makes gearing it down well worth it. Lathe is still in a shed and it's 28* out today. The lathe performed better after gearing down the stepper motor - this is similar to the tests i was performing previously. I do wish winter would get over though - it's cold out in the shed!

I spent some time looking at my lathe cross slide and carriage looking for the best way to mount my new magnetic scale while conversing with @WobblyHand about the scales he's trying to mount on his.
 
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Spent some time down in the shed making a bracket for the magnetic scales. For those following along - i purchased some very nice slim Sino scales but there were 2 issues with them - first was that i accidentally ordered 5um resolution scales, second is that the read head carriage/roller/plastic bits came broken and it wasn't reading correctly but i did a super glue fix on it and it seemed OK but as i was working it out with AliExpress i ordered 1um magnetic scales.

The glass scales have the read head below with the scale mounted to the side of the cross slide. The mag scales have the read head immediately to the right of the mag strip. Suffice to say i cannot reuse any of my bracket from one to the other.

Here's some pics of the ordeal; please excuse the mess.

PXL_20230321_001613138.jpg




PXL_20230321_001557384.jpg

The keen observer among you will notice that this is the block that i made backwards in post #11. I milled it down some more and made it work. There are 2 holes drilled in the end of the cross slide that the L shaped block attaches with. The screw closest to the scale has a notch out of the long side of the L to allow access to the screw and also the height needed to be trimmed so that it didn't rub on the ways when the cross slide was all of the way forward.

Overall it's within 5 thou but to adjust it any more it will need the holes enlarged a bit even though i'm using the factory screws. I had read that mag scales are more sensitive so i'm not sure how precise i need to be with this.

I have to machine the block that the read head sits on. One constraint that i'm trying to stick to is to not sacrifice tailstock travel with the DRO - the scale doesn't stick out any further than the gib screws so that's not an issue. I just need to make sure when i design the read head mount it doesn't interfere with the tailstock travel.


Might be talking to myself thoughout all of this but hopefully someone reads this and gets something useful from it - even if it's only entertainment value!
 
I was able to get the remainder of the work done on the X axis DRO scale today. Didn't get any pics but it seems to be coming together! Hooked both scales up to the Wobblyhand;s ELS. The Z scale is reading double what it should but since i first installed and tested with it i've upgraded the firmware so i need to be sure to check the settings.
 
I was able to get most of the loose ends wrapped up today - both scales are reading correctly, the back splash is back on, drilled a hole in the top left corner for the DRO cables to pass through and performed some general cable management. I fired it up and tested the features. Feeding and threading worked as expected. So excited and happy to have this. Working well. More to learn i'm sure but i've very pleased with the DRO and the ELS.

Here's some pics:

The way the DRO is mounted i didn't lose any tail stock travel:
PXL_20230326_140129190.jpg

Here's the finish with the fine feed:

PXL_20230326_152522763.jpg

Here's some testing with 13 TPI threading:

PXL_20230326_153518449.jpg

13 TPI followed by 56TPI

PXL_20230326_153733416.jpg

I couldn't be happier with this so far! :) Thanks to @WobblyHand for his patience, advice and assistance with this.
 
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