Old mini mill spindle motor question. Looking for current answers.

Think the old mini will be a good tool for my son to use until he builds some confidence. I did make a lot of money with that machine. You can do precision work with some patience and good indicators. I wore the motor out with 1.5" end mills and a 2" index face mill. Not to mention the bag of cheap plastic gears I went through. If we can patch that old motor to run for 30-45 days it might be worth hanging onto for training purposes. Will know more after someone disassembles the existing motor. May end up with some jb weld and turning the shaft. Actually thought about giving it to my bro-in-law, a retired machinist, to give him something to play with. I don't mind spending around $2000 for something a little better. The reason I hate to buy another new one for $500 is the short motor life. Within 12-18 months I would be right back in the same motor situation and still no real table size or hp to work with..
 
Just to make decisions more complicated, I offer this idea as a possibility: https://www.hobby-machinist.com/thr...lace-plus-big-current-draw.82636/#post-736074. I didn't do this, I just like the idea. Perhaps better on a lathe because it would facilitate an ELS mod. As a bonus, you would get very precise control over the RPMs.

The advantage is that the "motor" has a standard mount so you can more-readily swap in a replacement. The question is if it can deliver the RPMs and power you DO need; and if you want to spend the time to do the mod.
 
Well we got the motor fixed cheap. Son had 35 parts to square up pre-machining for the cnc. After 30 parts it appears the y axis feed nut is locked up on the mini. Will not budge in plus or minus direction. So today I have him sawing nearly 300 parts on my chop saw. Mini will be fixed during my next break after I finish 30 parts to fill pre-orders due Thursday. Now even more confident in decision to not pay $500 for another HFT mini mill. Still have not placed order for the Precision Matthews. Still on fence between models. Spent several hundred on material Friday so need to fill current orders to replenish my account. Probably order next Friday. Not enough hours in the day. Especially to keep repairing that mini. The lead screw and nut are cheap fixes. Think I will look for a bearing mod option for the mini y axis. No thrust bearings in the assembly dwg for y axis.
 
So here is the latest on the mini mill. First, to be completely honest, I ran the living dogs**t out of that machine for 15 months. No mercy at all. So to say it was long overdue for a good tear down and maintenance is a major understatement. I considered it disposable for the price. I am finally doing what I knew I should have done on day 1. Disassemble the carriage and table. I spent a total of 20 years in a major international machine tool manufacturing plant. I spent a few years in Quality Control there. I would have never inspected and accepted any part of the saddle and table. The casting has hospital burrs on it. The dovetails look like they were done with a hammer and chisel. The casting burrs were horrific. Ever edge that had anything close to a square edge also had a monster burr. So this is the perfect opportunity to teach my son about rebuilding. If he can work with me to tear it down and rebuild it then he should be able to repair it later himself. At least the manual end of it. So I spent 15 minutes disassembling. Then a solid 90 minutes removing tar that once was grease. So after a good wipe down with degreaser I started the deburr and honing process. Now the saddle is so smooth you can literally run your tongue around it. The dovetails are smooth and slick. Still plan on putting the spindle motor belt kit on it. The thrust bearing rollers look good considering the hardened caked grease. So tomorrow I will tackle the x table, the bearings and assembling it. Also need to spot the screw positions on the gibs to lock them in position. I counted over 300 parts for my son to start squaring up so after assembly he should have a smooth weekend. Still buying a Precision Matthews very very soon. Had enough sales in the last week to buy the model 25MV. Hope to clear my inventory this weekend to cover the cost of adding the power feed. If it is a real good sales weekend I will add the DRO setup. Not needed but why not get the whole package.
So the moral of the story is, if you buy a mini mill, particularly a HFT mini mill, do as I say and not as I do. Take it apart and fix it BEFORE you use it. You will appreciate it the next time you take it apart to repair or upgrade it. I think deburr and tap, translated in Chinese, means reburr and detap.
 
LittleMachineShop is open again. Son squared up nearly 300 parts on the mini this week. Since the teardown and re-assembly the machine is much smoother to operate and gibs are much tighter. Did shim the lead screw nuts to tighten up the backlash. Big restocking week. Ordered around 300 various bolts, 100 washers, 100 shipping labels, 2 new ink cartridges, 300 coin envelopes for shipping fasteners, another 100 priority shipping boxes and the belt conversion kit. Decided the PM25MV with power feed is the new machine that I will buy. The table is nearly double the size of the mini. Very close to my cnc mill table size. Now I need to start up production of roughly 350 parts using the floor drill press, the mini mill and the cnc. Son is going with the rest of the family to the Florida place for a week or so. Looks like I will be a busy bee for a while. Ready for the Precision Matthews once I clear enough space for it on the machining side of my garage.
 
Installed the belt conversion on the mini-mill. 2 thumbs up. Now the rpms really crank up. Much quieter. Been exchanging emails with Precision Matthews trying to decide between the 727 and 25 models.
 
If your motor is rated at 350 watts, that is less than 1/2 hp.. LMS specs the motor at .47 hp.

You might try this for a replacement motor. https://www.surpluscenter.com/Electric-Motors/
My guess is that you need a D.C. motor to go with your controller. You will need to determine the correct rpm. This should be on your motor plate. If, not, you can determine it by calculating the gearing ratios. You will also want to measure the mounting bolt pattern.
 
Well after 2 weeks of watching my son work his butt off on the mini mill I decided to sell it. Was squaring up 2" sawed blocks for the cnc. Every 4th part the gibs worked loose. Done. I purchased a new PM 728V-T mill with power feed and the DRO setup. Someone is on their way right now to buy the mini. Sold it for $725 with the new belt drive, a 3" machine vise, the clamp and stud kit along with the heavy steel table it is bolted down to. Win-win. Now the waiting for the new mill. Only 2-3 weeks. Pretty stoked.
 
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