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Sportandmiah
01-26-2009, 01:14 AM
I'm expecting my new HF Micro Mill in a week or two, and through reading many threads, I'm well aware of the build quality, dirt, shavings, grease, etc. I've never dis-assembled a Mill before, but I consider myself to be very mechanically inclined. :rolleyes:

That being said, is there anything that I should absolutely under no circumstances dis-assemble? My plan is to dis-assemble the entire Mill, and clean, grease, lap, re-tighten, re-adjust, and put back together.

isaac338
01-26-2009, 10:37 AM
I'm expecting my new HF Micro Mill in a week or two, and through reading many threads, I'm well aware of the build quality, dirt, shavings, grease, etc. I've never dis-assembled a Mill before, but I consider myself to be very mechanically inclined. :rolleyes:

That being said, is there anything that I should absolutely under no circumstances dis-assemble? My plan is to dis-assemble the entire Mill, and clean, grease, lap, re-tighten, re-adjust, and put back together.

In my experience with my mini-mill there's nothing on them you can't reassemble after disassembly if you're careful and use your head. The first thing I did to my mill was tear the whole thing down and press out the MT3 spindle for an R8 replacement. I hadn't even run the thing other than to make sure the motor worked before I had it in a million pieces on the bench.

When you say grease, I hope you're only talking about the transmission - I used white lithium in my transmission, but the ways all take oil.

Teenage_Machinist
01-26-2009, 12:02 PM
Yes. Be aware:


There are plain bearings for the lead screws. A bit tricky to align

THe ways get oil. I reccomend adding covers.

Parts diagram is included.

I would stay away from taking apart too much stuff in the drive box. The shifter is a bit complicated.

saltmine
01-26-2009, 12:14 PM
Mine came with all of the exposed parts coated with cosmoline. Automotive aerosol brake cleaner took it off nicely, but it also removes paint.
I spent the whole day cleaning and adjusting my HF mill before I even got to try it out. The tram was off, and the table gibs were all loose...The lead screws have always had slack in them. Eventually I'm going to replace the lead screw nuts...preferably with something a little more durable and tighter.
I also replaced those hideous hand wheels, with plated "ball&bat" cranks.
I gutted the drive box, and installed the belt drive conversion available from "The Little Machine Shop".....Made a much smoother running machine out of it.

Teenage_Machinist
01-26-2009, 12:18 PM
I have not ever broken gears, though I might some time. I blew fuses instead.

I have no quarrel with the handwheels. The nuts are awfully loose though, despite being split.

BillH
01-26-2009, 03:27 PM
Cleaning a Micromill is very easy. Simply break it down into the cast Iron parts, and steel parts. Buy an arc foundry furnace, throw the metal in, remove the impurities as they float to the top.

macona
01-26-2009, 03:54 PM
I'm expecting my new HF Micro Mill in a week or two, and through reading many threads, I'm well aware of the build quality, dirt, shavings, grease, etc. I've never dis-assembled a Mill before, but I consider myself to be very mechanically inclined. :rolleyes:

That being said, is there anything that I should absolutely under no circumstances dis-assemble? My plan is to dis-assemble the entire Mill, and clean, grease, lap, re-tighten, re-adjust, and put back together.

Dont lap anything. Just a good way to screw things up.

Peter.
01-26-2009, 04:08 PM
Cleaning a Micromill is very easy. Simply break it down into the cast Iron parts, and steel parts. Buy an arc foundry furnace, throw the metal in, remove the impurities as they float to the top.

Quality :D :D :D

Teenage_Machinist
01-26-2009, 07:57 PM
You may want to put self locking screws on the gibs. You can use vibra-tite or fishing line. I have had a ton of gib trouble. Also make sure the z gib is tight enough.

Buy a better chuck. After a few months my chuck went to crap, fortunately I have a good jacobs chuck.

saltmine
01-26-2009, 09:09 PM
You're probably not adjusting the gibs properly, if you're having trouble with them. I've still got the adjusting screws that came with it, on mine...And I've only re-adjusted them once to compensate for wear since I bought it.
The chuck is alright for drilling, but I went the extra mile and purchased a set of R-8 collets (one of the better decisions I made recently.)

To clarify a point, I upgraded to the belt drive conversion because I managed to bend some of the gear teeth in my spindle gearbox, and the "tweaked" teeth were imparting a vibratory pattern into the stock I was cutting...Once the belt drive was installed and adjusted, the pattern went away.

CLARKMAG
01-27-2009, 12:52 AM
How accurate a cut can you make on a HF micro mill?

If you put a 1"x6"x.25" piece of Alluminum in a vise, and cut it down to 1x6x.2", how tight a tolerance could you hold?
How long would that cut take?

Sportandmiah
01-27-2009, 02:23 AM
How accurate a cut can you make on a HF micro mill?

If you put a 1"x6"x.25" piece of Alluminum in a vise, and cut it down to 1x6x.2", how tight a tolerance could you hold?
How long would that cut take?

Not sure, but back to the topic at hand: Macona, you mentioned not lapping. I've read that lapping a new machine helps with the smoothness of the ways. Help a newbie and explain why you wouldn't.

macona
01-27-2009, 04:35 AM
I was a victim of the same "what they said" when I started out. I did what you were thinking of doing.

Smooth ways dont hold oil. The more surface area in contact means more friction. I think the ways were scraped flat from the factory on mine. With a scraped surface you get a whole bunch of point contact areas and the valleys in between hold oil. Even a milled surface will better than lapped. When was the last time you saw a machine tool with lapped surfaces? Some machines have ground ways but they usually have a lube system on them and the other side is scraped flat.

Smooth surfaces also experience stick-slip to a much greater degree than a scraped surface.

Even if the ways are just a milled finish I would leave them unless you want to learn scraping. You could take Forrest Addy's class.

Speaking of oil get some good way lube. Vactra #2 or Mobil Vacuoline 1409. Makes a world of difference. You can get vactra in a 1 gallon jug from grainger, enco, and most machine tool supply shops local to you.

Unless you have a surface plate and cast iron straight edges you wont have any idea what you are doing to the shape of the ways.

You will need to tram the mill when you get it though. Its a pain in the rear to do though, You have to put shims in between the column and base.

Clark, you are going to have a tough time milling the thickness down on a piece of aluminum like that on this mill. First you really have no way to hold it down. A 3" vise is about as big as you can go on this mill. Thats not enough to support it. You could use some 6" long parallels but as the material gets warm who knows where the ends are going to go. The tram will effect the finish and the stepping. You can use smaller mills and get less step per pass but the mill is so slow it is frustrating to use small end mills with it.

Sportandmiah
01-27-2009, 02:17 PM
Thanks Macona, I'll skip the lapping.

BillH
01-27-2009, 03:24 PM
Taig Lathes are lapped.
I'd get a Taig mill over a micro mill.

Sportandmiah
01-27-2009, 04:26 PM
For the price of $274 out the door I couldn't pass it up.