Advice/procedure for replacing/adjusting belt on harbor Freight Mini Lathe 93212

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BHKBHK

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Hi All,
I tried to search for an answer but did not see anything specific.


I'm new to this so please be gentle...

I picked up a mini lathe (used) and have been playing with getting it setup and testing it out.

I noticed it was slipping occasionally and I found the belt was just loose.
I also found the teeth on the belt and pulleys wearing, maybe it's just age but I want to replace them.

I broke it down to get to the belt and tighten it up... but the adjustment system is not logical, although it seems like it is at first glance.

I started by loosening the adjustment screws and trying to move the motor down to add some tension per the instructions.
This got the tension right, but then as I tighten the screws the motor seems to twist and noses up/down causing belt misalignment.

At one point I thought i had it dead on, but then when I went to tighten the 2 strews that just push against the motor (this makes sense if you have one), everything got jacked up.

Is there a correct way to do this and stop the motor from twisting?

Or am I over thinking the belt alignment and I just need to get the tension right and the cover will keep the belt in place?


...I do have replacement belts and pulleys but want to make sure I have the procedure right before I put them on as I do not want to destroy the new parts!

thanks
 
Sounds like there is something wrong with the motor mount- need to do a close inspection. Could be just sloppy manufacturing, common with these types of machines, but probably can be improved by filing or bending
-Mark
 
Little Machine Shop has a PDF of the mini lathe owner's manual. Pages 14-15 describe how to align the belt. If that procedure doesn't work you may need to do some repair or do some modifications to get it right. I've seen descriptions of owners using washers as shims to correct motor misalignment.

The OEM mini lathe motor mount scheme is notorious for being hard to adjust correctly. An online search will find mods that totally ditch the motor mount scheme. One uses a gate hinge -- that one can be found in the Files section of the groups.io 7x12 minilathe forum. You may have to join in order to download the file, but it's free. That mod does require drilling a few holes in the lathe. Luckily for me, I haven't found it necessary (yet) to lay a finger on the motor mounts for my 7x12. Fingers crossed....
 
homebrewed said:
Little Machine Shop has a PDF of the mini lathe owner's manual. Pages 14-15 describe how to align the belt. If that procedure doesn't work you may need to do some repair or do some modifications to get it right. I've seen descriptions of owners using washers as shims to correct motor misalignment.

The OEM mini lathe motor mount scheme is notorious for being hard to adjust correctly. An online search will find mods that totally ditch the motor mount scheme. One uses a gate hinge -- that one can be found in the Files section of the groups.io 7x12 minilathe forum. You may have to join in order to download the file, but it's free. That mod does require drilling a few holes in the lathe. Luckily for me, I haven't found it necessary (yet) to lay a finger on the motor mounts for my 7x12. Fingers crossed....
Click to expand...

I do not see my unit listed in their docs page.
The ones I did see are not similar mounting. Their mounting system is FAR superior I would say!

Perhaps I looked on the wrong page.
I can't seem to post a link here for where I was looking.

I'll go loolk at the other forum too.
thanks
 
If you click on the LMS "learning center" tab near the top of their home page you will find a link to their mini lathe user's guide. Is that the document you are referring to? If so, and it doesn't describe what you've got, you will need to get the owner's manual for your particular lathe. Sorry to get your hopes up!
 
homebrewed said:
If you click on the LMS "learning center" tab near the top of their home page you will find a link to their mini lathe user's guide. Is that the document you are referring to? If so, and it doesn't describe what you've got, you will need to get the owner's manual for your particular lathe. Sorry to get your hopes up!
Click to expand...
That is not where I was looking and it does cover my style.

I guess I am just having some sort of issue when i go to tighten the two vertically aligned screws as they seem to throw it out of whack.

I'll keep trying to do it and will try to be move even about it.


thanks!
 
tonydi said:
I have one of these lathes and this site shows how to adjust the mount type that I have on mine....
Mini-Lathe.com
Click to expand...
Yep, that is what I have also.
I just seem to have some issue with the two vertical screws causing misalignment when I tighten them.
Maybe I am over tightening them too.


I'll keep playing with it.




thanks for the links guys.
 
There might be something wrong with one or both of those vertical adjustment set screws. I was having a heck of a time adjusting the apron on the carriage (to get the split nuts to engage properly). Every time I tightened the bolts down the darn apron would move out of alignment. Closer examination of the bolts revealed that the bottom surfaces of the bolt heads weren't flat, they were round -- so tightening them down would cause them (and the apron) to center over the adjustment slots. Cheap OEM bolts. Replacing them with better fasteners solved the problem. I'd been thinking I needed to run an end mill over the bottoms of the slots to flatten them out so you can bet I was happy to discover otherwise.

I'd suggest taking a close look at those vertical adjustment set screws. Maybe the end(s) are mangled, malformed or the wrong form. Or perhaps they are just the wrong kind of fasteners -- putting plain old screws in there isn't a good idea because their ends probably are NOT flat. Or cup-shaped. Or anything else of a reproducible nature.

BTW, since the belt is toothed it doesn't need to be all that tight. You're good as long as the belt is tight enough so the teeth stay engaged while cutting (and aligned so the belt doesn't rub anywhere).

Keep on going, you will get it right.
 
Check out this mod:

Log In

groups.io groups.io
It would also help to relocate the controller box for easy access to belt adjuster.
Also, I recommend this mod:

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groups.io groups.io
 
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