[s2jesse]

Hey guys so I was working with my new 4th axis 8" super spacer and Its making some strange sounds. I cant tell if its binding, just vibration or maybe its resonance. It doesn't seem to be losing any steps but its definitely acting strange. I don't want to use it until I figure it out. I've adjusted the backlash per Tormach's video and it still sounds the same.

You can here it in the video here.. feel free to jump ahead to around the 1:35.

https://www.youtube.com/watch?v=om7GH3JPhyQ

Any idea whats causing this and how to fix?

Thanks!
Jesse

[Zetopan]

Since you apparently did not use a dial indicator I don't see how you could have adjusted the worm and when clearance correctly. Note that I do not have a Tormach 4th axis, but instead I made my own starting with a very robust rotary table that I have owned for many years and a Tormach X axis stepper motor (which is waterproof, unlike the Y and Z axes) and Tormach X/Y axis driver.

You need to measure the backlash at the OD of the rotary table at multiple rotational locations. And eccentricity of the worm or (for more likely) worm wheel can cause tight and loose clearances at various rotation angles. To check the backlash simple position the table at some rotational angle and using a test indicator see how far you can rotate the table by hand at that setting. e.g. Grip the table OD and try to turn it CW and CCW and see how much variation you can get on the test indicator. I think that Tormach recommends at least 0.5 mils (my table is *very* concentric and I set it to 0.4 mils).

Before doing the table wrestling you need to ensure that the worm has no significant end play. Likewise the worm could be too tight so always adjust the worm end play before proceeding with the above procedure.

[Concepts_Design]

I had the same noise when I got my 8" super spacer. I took it apart to clean it and found that there's two brake shoes in there and they are adjustable by two set screws. The set screws were adjusted too far to one side. Cleaned and lubed it. Set the shoes and backlash, no more problems

[s2jesse]

Since you apparently did not use a dial indicator I don't see how you could have adjusted the worm and when clearance correctly. Note that I do not have a Tormach 4th axis, but instead I made my own starting with a very robust rotary table that I have owned for many years and a Tormach X axis stepper motor (which is waterproof, unlike the Y and Z axes) and Tormach X/Y axis driver.

You need to measure the backlash at the OD of the rotary table at multiple rotational locations. And eccentricity of the worm or (for more likely) worm wheel can cause tight and loose clearances at various rotation angles. To check the backlash simple position the table at some rotational angle and using a test indicator see how far you can rotate the table by hand at that setting. e.g. Grip the table OD and try to turn it CW and CCW and see how much variation you can get on the test indicator. I think that Tormach recommends at least 0.5 mils (my table is *very* concentric and I set it to 0.4 mils).

Before doing the table wrestling you need to ensure that the worm has no significant end play. Likewise the worm could be too tight so always adjust the worm end play before proceeding with the above procedure.

I just followed the instructions in this vid. I'll give it a check with an indicator next tho thanks.
Adjusting the Backlash on a 4th Axis | Milling Around

[s2jesse]

I had the same noise when I got my 8" super spacer. I took it apart to clean it and found that there's two brake shoes in there and they are adjustable by two set screws. The set screws were adjusted too far to one side. Cleaned and lubed it. Set the shoes and backlash, no more problems

Thanks! ill measure backlash and open her up and take a look at the set screws as well! Thanks guys

[Zetopan]

I just followed the instructions in this vid.

Firstly, it appears that autocorrect or something seriously altered my message to near unintelligibility. My corrections are shown below.
“could have adjusted the worm and wheel clearance”
“Any eccentricity of the worm”
“backlash simply position”

Secondly, the instructions in the video are what I would consider to be quite sloppy.
1. He never measures the actual backlash of the rotary table at any position.
2. He assumes that the worm wheel is exactly concentric.
3. He assumes that tightening the locking setscrew (or nut) does not affect the backlash set screw position.

If you want precision with non-binding operation you need to check the backlash with the table at several different rotary positions. Due to wear or manufacturing imperfections there could be tight and loose spots in the rotary table positioning. I have seen some small rotary tables that had multiple mils of backlash because the worm wheel was sufficiently eccentric that the clearances at the tight spots caused a lot of slop at the loose spots. Run away from those types of rotary tables.

Your first step should be to adjust the worm end play, if it is adjustable. Your second step should be to locate any tight spots by evaluating the backlash at several different degree settings. Any backlash change with rotation suggests wear or other imperfections. The final backlash adjustment should be made at the tightest spot, if one exists (ideally none will be detectable). When you make the backlash adjustment you need to adjust the backlash setscrew appropriately and also lock it in place with the locking (short) setscrew (or nut) before measuring the backlash. If you do not tighten the locking setscrew before making the measurement the backlash setscrew could move when the locking setscrew (or nut) is tightened, altering (increasing or decreasing) your backlash setting.

[keen]

Hi - It could be your worm drive shaft needs cleaning out - mine was contaminated.

Keen

https://www.youtube.com/watch?v=G9jTrcPjd0s

[s2jesse]

Thanks for the info guys... Will do any tips on disassembly? Anything to watch or be careful for?

[keen]

Thanks for the info guys... Will do any tips on disassembly? Anything to watch or be careful for?

Make sure the worm is swung fully out of mesh before trying to remove the worm or wheel assembly. Don't use force - Ask a question if you get stuck.

Cheers Keen

[philbur]

The ring gear will never run exactly concentric with the ring gear bearings (on a low cost table) so even if you adjust backlash with the worm at one point on the ring gear (as per the procedure) the worm may still bind at other points on the ring gear due to the eccentricity of the ring gear.

For a test back off on the backlash until you can feel backlash for the complete 360 degrees and then rotate the table under machine control. If there is no vibration then adjust the backlash in stages until you have the start of vibration at some point in the rotation of the ring gear, then back off a touch, you have it set as good as is possible.

Phil

PS: the step in the milled circumferential slot is probably due to deflection, you should be using a tailstock with that much overhang.

[s2jesse]

The ring gear will never run exactly concentric with the ring gear bearings (on a low cost table) so even if you adjust backlash with the worm at one point on the ring gear (as per the procedure) the worm may still bind at other points on the ring gear due to the eccentricity of the ring gear.

For a test back off on the backlash until you can feel backlash for the complete 360 degrees and then rotate the table under machine control. If there is no vibration then adjust the backlash in stages until you have the start of vibration at some point in the rotation of the ring gear, then back off a touch, you have it set as good as is possible.

Phil

PS: the step in the milled circumferential slot is probably due to deflection, you should be using a tailstock with that much overhang.

Thanks guys I'm def gonna clean her out and set it all more scientifically

[scott216]

After reading this thread, I decided to take my Super Spacer (6 inch) apart to see how it looked inside. Everything was nice and clean. I didn't take the worm gear out, just unscrewed the bottom and removed the index plate and ring gear. I haven't used my Super Spacer yet.

My Super Spacer came with a bunch of round plates with various notch patterns. What are these? They seem like some sort of index plate, but I don't know how to use them. Nothing about them came with the Super Spacer.

For lubricant I used LubriMatic High Performance Gear Lubricant SAE 80W90 EP. Is this a good choice?

Here's a link to picture of the label: https://goo.gl/photos/4nqfNyFryn38apza8

[keen]

After reading this thread, I decided to take my Super Spacer (6 inch) apart to see how it looked inside. Everything was nice and clean. I didn't take the worm gear out, just unscrewed the bottom and removed the index plate and ring gear. I haven't used my Super Spacer yet.

My Super Spacer came with a bunch of round plates with various notch patterns. What are these? They seem like some sort of index plate, but I don't know how to use them. Nothing about them came with the Super Spacer.

For lubricant I used LubriMatic High Performance Gear Lubricant SAE 80W90 EP. Is this a good choice?


Here's a link to picture of the label: https://goo.gl/photos/4nqfNyFryn38apza8

Hi - It was my worm gear shaft that was the most contaminated. Keen

[SpruTormaCam]

I had the same noise when I got my 8" super spacer. I took it apart to clean it and found that there's two brake shoes in there and they are adjustable by two set screws. The set screws were adjusted too far to one side. Cleaned and lubed it. Set the shoes and backlash, no more problems

Sounds like I have the same issue with my old 8". I suspected it was brake related as it happens only in one direction. Did you follow any directions or drawings? I was reluctant to tear into it and get in over my head but seeing your post has me more motivated to proceed. Any tips or references would be greatly appreciated.

I need to fix this as very seldom it will skip a step out of the blue which pretty much renders the 4th un-usable (unless I only rotate the one direction).

[Concepts_Design]

Sounds like I have the same issue with my old 8". I suspected it was brake related as it happens only in one direction. Did you follow any directions or drawings? I was reluctant to tear into it and get in over my head but seeing your post has me more motivated to proceed. Any tips or references would be greatly appreciated.

I need to fix this as very seldom it will skip a step out of the blue which pretty much renders the 4th un-usable (unless I only rotate the one direction).

there are no drawings to follow, just open it up and take a look. you can take the brake right out of there, it's only for locking the table so shouldn't really need it. There's not much too the thing.

[Jim Dawson]

Sounds like I have the same issue with my old 8". I suspected it was brake related as it happens only in one direction. Did you follow any directions or drawings? I was reluctant to tear into it and get in over my head but seeing your post has me more motivated to proceed. Any tips or references would be greatly appreciated.

I need to fix this as very seldom it will skip a step out of the blue which pretty much renders the 4th un-usable (unless I only rotate the one direction).

I had the same problem with mine. Here is how I fixed the sticky worm shaft, it was sticky due to poor design.

Scroll about halfway down the page

http://www.cnczone.com/forums/linear...onversion.html