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Harbor Freight mini mill

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DennisK

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#1
Well,after about 2 months of messing with my mini mill,I finally did what hundreds of other have done; broke the plastic gear.And I didn't just chip a few teeth off,I shattered it. It came out in about 5 pieces.So,I was wondering what other people have done when this happened to them. It seems to me there are 2 options. The metal gears replacements,or convert to belt drive. I'm leaning towards the metal gears because they are a third of the price.Does anyone know if you have to be Mr. Goodwrench to change these(there are 3 gears in the set), or can just about anyone do it? TIA
 

chuckorlando

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#2
If you can run a mill you can change a gear. Mechanic work is nothing more then nuts and bolts. Be it a spark plug or a cam shaft it just bolts together.:wrench:
 

David Kirtley

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#3
That plastic gear is the weakest point. It is especially prone to failure on interrupted cuts. I did change the gear in my spindle on my lathe and it wasn't too bad but still a pain. I put the metal gears in and they were really noisy in comparison. The mill is about the same arrangement. I did the belt drive conversion on my mill but never broke a gear. I put the belt on just after I got it.

It is much nicer with the belt drive. No regrets and I would do it again in a heartbeat. Quiet. Smooth. If I stall it out, the belt just slips a bit.
 

DennisK

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#4
That plastic gear is the weakest point. It is especially prone to failure on interrupted cuts. I did change the gear in my spindle on my lathe and it wasn't too bad but still a pain. I put the metal gears in and they were really noisy in comparison. The mill is about the same arrangement. I did the belt drive conversion on my mill but never broke a gear. I put the belt on just after I got it.

It is much nicer with the belt drive. No regrets and I would do it again in a heartbeat. Quiet. Smooth. If I stall it out, the belt just slips a bit.
Since I lost much of my hearing over the years,I doubt a little extra noise would bother me. Did the belt conversion kit come with the belt,or was that an extra cost?
 

n3480h

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#6
Get the belt drive conversion - you won't regret it. I shattered my plastic gear early. Installation was easy, took 15-20 minutes. Much quieter, and far more forgiving.

Tom
 

DennisK

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#7
Get the belt drive conversion - you won't regret it. I shattered my plastic gear early. Installation was easy, took 15-20 minutes. Much quieter, and far more forgiving.

Tom
I understand all this,but the cost is 3 times the price of the metal gears. I would like to also be able to buy their tool post grinder. Has no one used the metal gear upgrade?
 

Flammable_Solid

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#9
I did the belt drive upgrade, ordered the eBay kit. Would do the LMS kit if I had to do it over.

I have my take-off gears and my back up set of gears you can have. Send me a PM with your address.
 

DennisK

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#10
I did the belt drive upgrade, ordered the eBay kit. Would do the LMS kit if I had to do it over.

I have my take-off gears and my back up set of gears you can have. Send me a PM with your address.
I appreciate that, but I just ordered the belt drive from LMS. Thanks anyway.
 

pojotex

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Feb 21, 2014
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#13
Thanks, I couldn't remember where these files came from. They should be used before you break the gear..... o_O
 

Boot

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#14
Get the belt kit from LMS and you won't be sorry. Metal gears will only cause you to break other gears or other parts of the mill. Two worth while upgrades to this
machine are the belt driver kit and the air shock head support instead of the spring arrangement it comes with. The spring counter balance was probably the reason for breaking
the plastic gear. If you don't replace it with the belt drive eventually you will break something else. Both kits are simple to install. Very good instructions. If
a dumb ass like me could do it anyone could even your wife or girlfriend.
 

NodakGary

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Mar 21, 2012
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#15
Yup I broke my gears about a month ago. I ordered replacements from LMS.com. They came quickly and were no problem getting in. I had also broke the 2 speed gear and when I ordered the replacements I ordered 2 sets of each. LMS is very nice to deal with and their parts can be ordered for each brand of machine.
Good luck.
In case you have to replace the 2-speed gears on the inside of the unit, here are a couple of hints that I can remember from doing mine. If you only tore up the top gear you are lucky. If you can put the unit in slow and then high speed and turning the lower end of the spindle rotates the upper gear the 2-speed gears should be okay. If the upper gear only turns when in one or the other gear, you better tear it apart and check the 2-speed gear cluster.
Be sure to look for the little keepers on the shafts as they could be real bear-cats to try to find when putting things back together. I would wrap the motor in some cloth to protect the finish while you have it off, chipped the paint on mine in a couple spots. And don't forget to lube the heck out of all the mechanisms before you cover everything up. You may appreciate the help of a friend while taking it apart and putting the unit back on the column again, it is quite heavy. I had time to put together a little hoist to help me.
It may be handy to cover the top of the column to prevent anything from falling down inside it, don't ask me how I know. And if you have to replace the 2 speed gear on the inside I removed the 4 bolts from the back side of the column side of the unit so as to be able to get at the high-low speed selector shaft set screw. Be very careful to set this selector correctly when re-installing it. (Mine hit the back of the electrical box before the selector was centered on the gears.)
NodakGary
 

Boot

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#16
Why bother replacing gears when you are only going to break them again. Apparently you never read about using a belt conversion from LMS. It's the best
investment you could of made for that machine. Two things this machine needs is a belt drive and a gas shock assist for the head instead of the spring and
lever set up it comes with. Check and read what LMS has to say about both and you will agree with them. The both conversions are easily done in 15 minutes
with out the loss of any parts down in to the gears of the machine. Boot
 

cnctruckeic

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#17
I just wanted to ask a question about the Belt conversion. I broke the 2 speed gear and teeth on one of the gears on the spindle.. Yea I know...I need to learn to use a Fly Cutter.. But I did order the belt drive from LMS and was told that drilling a 1/2 hole would not work with the belt drive since the torque was so low... Just asking if you guys have had issues ..ways around it..
Thanks
 

Charles Spencer

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#18
I have the LMS belt conversion but I never tried drilling a 1/2" hole with mine.

Of course the 5/8" holes I drilled came out OK.

I don't think I'd try drilling holes much larger than 1/4" without drilling a pilot hole on any machine.
 

cnctruckeic

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#19
Well broke gear and lost low gear tried to drill a hole 15/32 and motor kept cutting out

Sent from my SM-N910V using Tapatalk
 

silence dogood

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#20
I just checked my email. LMS has their Belt conversion kit %10 off regular price right now till Jan 31.
 

cnctruckeic

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#21
I bought it.. should be here today. . Looking forward to getting my mill back up and running..

Sent from my SM-N910V using Tapatalk
 

9t8z28

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Aug 16, 2016
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#22
I have the belt drive and yes it is a little more difficult to drill a half inch hole but it is doable. Think of it this way, if you're drilling a half inch hole with the plastic years you'll have a higher probability of breaking a gear. With the belt drive, if you're having trouble making the cut the only issue you'll have is stalling out the motor. Just go slow on your feed and use lubrication. Honestly this is about the only negative that I could think of in regard to the belt drive. Everything else you use it for will be much improved and quieter than the stock plastic gear set up.
 

jocat54

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#23
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