Thread: MH-28V Mill

I've been looking for a mill to keep my lathe company since the start of the year. Having increasingly needed one, I thought I should be making some kind of decision. It came down to the HM-46/47/48 from H&F, the "Optimum, but not really" BF-30 from Redfox or the Optimum MH-28V from H&F. I decided the BF-30 was going to be a bit too expensive in terms of freight, although I liked the idea of its 2.2kW variable speed motor, 3 speed gearbox and auto tapping mode, but the delivered price is something like $4,700 versus $3,200 for the MH-28V.

There's a useful thread comparing the HM-46 and the MH-28V here:
https://metalworkforums.com/f223/t20...co-mill-drills

Which concludes that the Optimum machine is considerably lighter-weight that the HM-46, which makes sense, as the latter is 50kg heavier. However I kind of trust that the Optimum machine is likely to be better finished than the HM-46, I like the variable speed, and there's a bunch in Qld who flog plans, instructions and support for a CNC conversion for the MH-28V, which is something I'm fairly keen on, keeping in mind the caveats mentioned here regarding hobby-grade CNCs.

I'm not totally decided yet - I'm going to get a price from the local dealer who resells the H&F range, and see if they have a compelling opinion.

Regardless of what I get, I also need to sort out some initial tooling & a vice. All I have at the moment is a set of HSS endmills... I'm thinking an MT3 to ER32 chuck and some collets would be a good start, but any suggestions, particularly in regards to a vice would be appreciated.

I use a pair of cheap Chinese grinding vices I bought from Mag-pro keyed together on a sub plate. Works a charm.

The local dealer did me a price that was $400 cheaper than H&F, coming out to $2800 with stand. H&F would have included delivery to my house, but the local dealer is only 10 minutes away, and has an ex-toolmaker staff member run up and check over the machine prior to me picking it up, so a great deal overall.

The machine is only abut 240kg (the stand is an extra 54kg) which is not exactly massive, but still not something you can shift by hand. So I used a tractor:
IMG_2848.jpgIMG_2849.jpg

And a Supercheap engine crane:
IMG_2850.jpg

Which, despite the SCA pedigree, actually seems to be a really sturdy, well finished bit of kit.

Had I read the manual I would have discovered that it's OK to lift the unit by the head, but I got it done.

Only problem - I assumed it came with a drill chuck. It doesn't, just an arbor, so all set up, but can't try it out

Hi RustyArc,

That Optimum is virtually identical to mine ! The controls on the panel are the opposite way round (left, right) and the table looks to be a little shorter. I cant tell from your pictures but the motor on mine is rated at 750 watts or 1 hp. I built a table feed unit for mine using a window screen wiper motor. I did a write up on it somewhere. Mine also came with a 16 mm B16 taper drill chuck a suitable mandrel and a nice MT3 collet chuck.

A couple of tips. Get yourself a suitable square socket key for the M12 threaded drawbar with a five or six inch "T" bar handle. One other is that there is no means of locking the spindle to remove the tooling when tightening or loosening the collets or removing tools from the MT3 taper. So I have a 100 mm length of 10 mm aluminium bar that I stick into the wedge slot where you would use a wedge to remove a tanged drill. Make sure that you don't forget that its in there and start the motor or you will be looking for some 20 mm 10 amp fuses and possibly a new plastic gear.

Congratulations their a nice mill.

Nice Mill BaronJ

please keep us posted on how you find the machine as you start to use it. First hand experiences and thoughts are always useful. I’ve been looking for a mill for a while and considered the Sieg sx3 as a benchtop option if I couldn’t find a suitable second hand turret mill. Did you consider the Sieg machine at all and if so what was a deciding factor against it for you?

Congratulations rusty!

Sounds like you did a really good deal. I have only ever heard good things said about the brand Optimum.

At 54Kg, that stand would be quite solid for that mill. Looks quite well made too.

Simon

Originally Posted by Danger Mouse

Nice Mill BaronJ

I’ve been looking for a mill for a while and considered the Sieg sx3 as a benchtop option if I couldn’t find a suitable second hand turret mill.

The one great feature of the Sieg is the push button tapping ! Push the button to start tapping and then let the button go and the mill immediately reverses unwinding the tap.

Now that is a modification that I would like to make to mine !
More round toits.

Originally Posted by BaronJ

Hi RustyArc,

That Optimum is virtually identical to mine ! The controls on the panel are the opposite way round (left, right) and the table looks to be a little shorter. I cant tell from your pictures but the motor on mine is rated at 750 watts or 1 hp. I built a table feed unit for mine using a window screen wiper motor. I did a write up on it somewhere. Mine also came with a 16 mm B16 taper drill chuck a suitable mandrel and a nice MT3 collet chuck.

The 28V has a 1.1kW variable-speed motor. Based on other machines I'd been looking at, I had assumed it'd come with at least a jacobs chuck and maybe a face mill or something. Nope, just came with this stuck in the quill:
IMG_2852.jpg

Which, somewhat oddly, is a JT6 size arbor, which takes a 13mm chuck, rather than at JT3 which takes a 16mm chuck. Doesn't matter that much as most drills above 1/2" tend to be reduced shank.

A couple of tips. Get yourself a suitable square socket key for the M12 threaded drawbar with a five or six inch "T" bar handle. One other is that there is no means of locking the spindle to remove the tooling when tightening or loosening the collets or removing tools from the MT3 taper. So I have a 100 mm length of 10 mm aluminium bar that I stick into the wedge slot where you would use a wedge to remove a tanged drill. Make sure that you don't forget that its in there and start the motor or you will be looking for some 20 mm 10 amp fuses and possibly a new plastic gear.

Undoing the drawbar just once with a spanner had me thinking of a cordless drill, and it turns out a 3/8" extension mounted in one works well, but the T-wrench makes sense for any torquing that's needed, and maybe fast enough that motorised assistance isn't needed.

My machine came with a 36mm wrench that engages flats on the end of the spindle, so while I don't have a collet chuck yet, I was thinking that'd take care of holding it still when tightening the collet nut?

Originally Posted by Danger Mouse

please keep us posted on how you find the machine as you start to use it. First hand experiences and thoughts are always useful. I’ve been looking for a mill for a while and considered the Sieg sx3 as a benchtop option if I couldn’t find a suitable second hand turret mill. Did you consider the Sieg machine at all and if so what was a deciding factor against it for you?

Dunno if this was addressed to me or BaronJ, but as per my initial post, I really only looked at the HM-46 and a few other mills - I did have a quick look at some Sieg machines, specifically the SX3L "high torque" model, which while having good specs, seemed a little light at 162kg, and the SX4, which at 1.5kw and 310kg seemed like a more capable machine, but at $4.4k with stand plus freight was starting to get pretty expensive. Also, finding the CNC conversion guide for the 28V and a good price from the local dealer pushed me over the line.

After my initial frustration that couldn't do anything with the machine due to lack of tooling, it occurred to me that I did in fact have a set of MT2 drills and an MT2 to MT3 adaptor. So I removed the drawbar and installed a 16mm drill bit, piloted a couple of holes on the drill press, then mounted up a bit of flat bar in a precision vice and drilled some holes.
IMG_2851.jpg

I put the machine in low gear and the speed dial on minimum, which had the bit spinning at 130RPM or thereabouts. However, as the bit started chewing into the work, loading the machine, it actually sped up to around 240RPM, and slowed down again once the load was reduced. It kind of makes sense, but very odd behaviour all the same.

Also, there's a pause between pressing the start button and the spindle starting to turn - I don't believe there's any technical reason why this should be the case - no other machine with variable speed has the same kind of pause. It's not a huge thing, more of a niggle.

I picked up a 13mm chuck to fit the supplied arbor, which allowed me to try some actual milling. I chucked up a 3/8" HSS endmill, mounted some 12mm scrap steel in the precision engineering toolmaker's vice and had a go.
IMG_2853.jpg

Seemed to work OK, but I need to sort out my feeds and speeds. A 4mm DOC with this setup (can't remember the revs) seemed fine, although I think the limiting factor might have been the vice.

Originally Posted by RustyArc

Undoing the drawbar just once with a spanner had me thinking of a cordless drill, and it turns out a 3/8" extension mounted in one works well, but the T-wrench makes sense for any torquing that's needed, and maybe fast enough that motorised assistance isn't needed.

My machine came with a 36mm wrench that engages flats on the end of the spindle, so while I don't have a collet chuck yet, I was thinking that'd take care of holding it still when tightening the collet nut?

Hi Rusty,

Don't use a cordless drill on the drawbar ! You will find out why when the chuck falls out and does some damage. I've just measured the length of the "T" bar in my square socket key. I've surprised myself, because the "T" bar just clears the motor housing.

31-07-2019x001.jpg 31-07-2019x003.JPG
I had got it in my head that it was longer than that.

The other point is don't use the flats on the top of the spindle to hold it whilst loosening the drawbar, you will unscrew the cap retaining the drawbar. Drop the spindle an inch an use a piece of alloy rod to lock it. That spanner is so you can remove the cap and lift out the drawbar. I have two, one is M12 and is the one that normally stays in there, the other is 1/2" whitworth, but I don't think I've ever used it.

Last but not least, don't use a drill chuck for milling cutters ! Again the chuck will fall off at some point, usually when you are in the middle of a cut. I've seen it happen and the cutter went through the blokes trousers and into his leg. Very bloody !!

Just so you know, it wasn't me it happened to.

Indeed... Drill chucks are for drills.

I'm sure you know that the mill is the cheap bit, the tooling is the 'essential accessory'..

Get some collets to hold your cutters.

ER seems to be very popular these days, either er25 or er32 according to your requirements.

There are other choices though.

Russ

I'm expecting an ER32 collet setup next week, at which point I'll work out the mechanics of tightening collet nuts, but I would have thought using the 36mm spanner on the bottom of the quill while tightening the collet nut would have done the job? The retaining cap for the drawbar takes a 25mm spanner, but I got the impression its tightness is not particularly critical.

Hi Rusty,

We are talking about two different things ! There are no spanner flats on the bottom of the quill or the spindle.
There are however two holes for a pin spanner in the nut holding the bottom bearing.

I have the supplied spanner that fits the drawbar retaining collar.

My supplied milling collet chuck doesn't have the flats that the ER collets have, you would use those to tighten the ER collets. In any case removing the ER chuck from the mill spindle means that you have to lock the spindle somehow in order to loosen the drawbar ! That is why I mentioned using an alloy rod in the wedge slot to lock the spindle.

Yes you could also use the ER collet chuck flats, but what about the drill chuck ? Unless the chuck key "T" bar fits the holes in the chuck you cant use that as a lever. Mine doesn't but its easier and quicker to do it the way I've suggested.

Originally Posted by BaronJ

There are no spanner flats on the bottom of the quill or the spindle.

IMG_2854.jpg