Looks can be deceiving. Most Harbor Freight stuff is well known for its very high coefficient of crapitude.
Hmmm all the finding the right machine, checking tolerances/backlash/ect. makes me think how this is a better deal every time I look at it…
Yeah I know if you are going to dream… Dream big. Side note I have been thinking about getting a small milling machine for a while, you know as a hobby to burn every spare penny of my kiddo’s college tuition, that flash lights, camera gear, and cars have not yet done the trick to. LOL.
Fixtures, how to get things done right vs. how to get things done right now, and replace tooling…. Not that I have ever done that, to anyone’s knowledge…
oh wow…a local machinist!
nice work, especially on using an endmill holder (MT3 taper? how's it held in?) instead of the chuck. I did much the same to my drill press, using one of those crappy but now heavily modified HF X-Y vises:
It does surprisingly decent work, within pretty major limitations. Still, it allows me to do a lot of things I couldn't otherwise do, so that's what matters. Wish mine had a rack and hand crank for the table as it's bloody heavy. I need to rig up some kind of hydraulic jack underneath to help out.
Thanx comfy! Another great thread. I too really want to know if that HF mini mill is any good. I know bout HF, just comfy seems to, sort of, perhaps, recommend it, maybe?
Actually the online reviews are pretty favorable, interesting...
On the subject of doing without proper machines, there is a series of books on building a machine shop from scrap.
http://gingerybookstore.com/index.html
Even if you have no intension of building machines from scratch There are some good examples of making precision parts without precision tools. And it’s not that much more work to start from scratch then it is to upgrade every part of a tool to make it work in ways it was never meant to.
The 'Harbor Freight mill' isn't actually anything to do with Harbor Freight, nearly all those import lathes/mills are made by Seig, rebranded to suit by the resellers. http://www.mini-lathe.com/Mini_mill/Versions/versions.htm
Upgrade parts that fit one will fit the others, the minor differences between them, if any, are all in the replaceable parts. Paying more for one from someplace like LittleMachineShop just means they have specced the machine built for them by the OEM to use higher quality parts where the bargain-basement versions might have skimped a bit to get the price down to the minimum. A bargain-basement model with the upgrade/replacement parts from LMS will end up being the same machine as the more expensive one (a possible benefit of buying the cheaper one and then upgrading it is that you'll still have the original parts as spares if/when something goes wrong).
After lusting after a lathe for so long I'm coming around to the reality that a mill (or something that can do mill-like operations) is more useful more often than a lathe. I'm still going to get a lathe eventually though, next time HF offers another store-wide 20% off coupon and I have a spare ~400. The 7x10 comes out to $399 with the 20% off coupon.
After I replace/reinforce my drill press column, I guess the next weak point will be the lame JT33 spindle taper, which I can't do anything about since it's a 1-piece shaft. I used it for a while with a cheap Shars 1/2" keyless chuck, but the taper is too small and it doesn't engage enough of the shaft, hence it's prone to falling off. It also doesn't help that the overall length is about double that of the standard 1/2" keyed chuck, which just doubles the leverage applied at the spindle taper. The more compact keyed chuck is the way to go (though a quality chuck would be a good investment over the cheap one that ships with the Skil, the stock chuck is garbage).
I don’t think you’ll be able avoid the problems inherent to that JT33 taper. Your best bet would be to make an end-mill holder for what ever shank end-mills you use, grind a couple of flats on the taper and use set screws (I’ve seen others do this). That’d be tough to make without a lathe, but you could possibly rough “mill lathe” the taper and then use a JT33 reamer (if available) to finish. I guess you could also somehow drill and tap the end of the spindle and secure the chuck with a bolt up through the chuck. Otherwise you’ll always be at risk of knocking the chuck off and ruining a piece of work.
The keyed chucks have never fallen off, that only happened with the super-long keyless turd thing. The big end opening is only .615", and that put it too far down on the taper with not enough grip. Runout on it was pretty bad as well though I think that was unrelated to the taper thing.
never say never!
If doing this to cast iron didn't knock it off, I don't think anything will. :D
>raises arms in defeat< sure, although I’ve seen a chuck come off doing just that 
As my mum says, opinions are like arseholes, everyone has one!
Depending on what it's cutting it does rattle and vibrate all over the place, but the cuts look good and the chuck doesn't fall off. Life for the chuck/spindle/taper should only get easier after fixing the flexi-column.
Hey Comfy, how about using some 1/2” 7075 rods as the stiffeners and pouring JB Weld in as the filler? With 5 rods there wouldn’t be a lot of filler space and you could get a commercial pack of the epoxy. Once that set up, it would/should be about as rigid as a solid bar. Lighter weight too.
If you could have the Drillpress shaft re-tooled to a MT4 taper then you could use a host of various machine tools & chucks. I’’m not sure if a JT33/MT4 adapter is availiable, but i do have a MT4/JT33 collar adapter to use Jacobs chucks on my current mill/Lathe unit here.
Dale- I've already ordered the 24" long 6061. It could get interesting trying to fit it all together, as the original column is 2.344-2.35" OD, the new stuff is listed as 2.375" OD (though actual dimensions in raw stock can vary a bit). Once I have all the parts laid out, if the base & headstock are too small for the new column, I'll evaluate the best way to deal with it. Either have the ends of the barstock turned down, or open up the bores on the head & base. The clamp mount for the table won't be an issue as it can be expanded to fit over quite a large range of sizes.
If I had gone the fill/reinforce route, most likely I would have dropped in a thick wall tube down the center, then filled the outer space with cement. Stiffer than a solid section of cement alone, and also lighter, and needs less filler. JB Weld in the 10oz kit is cheap, but not that cheap... that would probably cost more just for the JB than the 6061 barstock, even if just using it to fill the space between an internal tube & the original column.
Dan- I've kinda studied the various taper sizes here (http://littlemachineshop.com/Reference/Tapers.php), but not well enough to really pin down if there's a better taper that's smaller on both ends so that the JT33 could be cut down without adding material by welding first. The catch is that if it's cut down the new taper has to be something that has a reasonable selection of useful parts that fit it. I'd only attempt welding & regrinding if I had a spare shaft beforehand, in case it goes wrong, and I haven't searched around to see if replacement spindles are available anywhere. Also there's no place local that could do the grinding, it would have to be sent out to some other civilized part of the world.
The replacement parts list is most unhelpful, lol: http://mdm.boschwebservices.com/files/3320partslist%20r48652v5.pdf
Nice job comfy… You can attach a digital caliper to the vise too- I’ve done before it and it works… Milled aluminum down to a 10th of an inch accurate. It’s a lot easier than checking your work. There’s a lot of ways to make a ghetto mill for around 400 bucks. Harbor even sells a cross vise but shimming that sucker will take a day or so lol
2’ of 6061 for $50 is about the most solid way to fix it I would think. At that diameter it doesn’t make sense that it could flex in less than 2’ between pressure points.
There's actually pourable stuff made for stiffening thin castings like thin wall cast iron engine blocks. Commonly done on drag engines, poured into the water jacket to support the cylinder walls where it's not possible or practical to install thickwall sleeves. Tougher than cement/concrete.