Thread: Hafco HM-46 questions

Hi Guys,

Picked up a nice combination of an HM-46 mill and AL336D lathe last weekend for an excellent price. Both units look to have done very little work and came with a bunch of accessories and add-ons. Big step up from my Chinese BV20 bench lathe and a drill press!

Got a couple of questions about the HM-46 though. Could I please indulge the brains trust in some dumb questions?

1) There is a short length of orange plastic tubing coming out of a fitting on the top of the headstock. The manual refers to it as a "radiator pipe" in the parts list but its function isn't referred to anywhere else in the manual. Forgive my ignorance but what the heck is this for? OK turns out this is a breather for the gearbox despite the odd name!

2) The drawbar top has a black plastic cover over it - do you remove and replace this every time you change tools or is one of those things that you remove and leave on the spares shelf? Seems a bit tedious to have to put it back on each time?

3) The spindle clear plastic safety shield is still fitted, I had planned to ditch this and bypass the safety switch but wanted to check with the brains trust if this was a bad idea first? I find safety shields on the lathe an annoyance and don't use them (I use proper safety glasses religiously though) - is it the same with the mill?

4) The headstock on the HM-46 was empty of oil and the XY table was full of oil so looks like there might be a leak there. Before I refill the gearbox and go leak searching, is there a common point of failure for leaks in these?

5) Lastly, I want to add a DRO to the mill, ideally 3 axis. For the Z axis do you just fit the DRO scale on the main head of the mill and forgo the ability to measure the quill? Is there a device you can fit to the quill itself for that?

Firstly yes the tube at the top is a vent. The 'Radiator Tube' Asian's have a weird way of describing some things or just poor translation. The drawbar cover is a safety feature to give you protection from a rotating part, but it's completely up to you. I tended to put mine back on each time I changed a tool unless I was doing frequent tool changes. I would be putting the cover back on when the Mill is not in use though. The spindle shield is there for your protection, but if your wearing safety glasses or a face shield you might be safe enough. My DM-45 Mill Drill never even came with a safety shield.
I can't help much with the oil leak as I pulled mine apart so I could replace the faulty Z-axis gibb which I still haven't got around to doing, but it's probably a seal. I had planned to fit a 3 axis DRO to mine, which was going to X, Y and Z. The Z axis scale was going to on the column. You can buy a vertical digital scale to go on the quill and there's plenty of places that sell them https://www.machineryhouse.com.au/M733 and https://www.ebay.com.au/itm/13230220...UaArnZEALw_wcB and if you go onto eBay or just Google 'Quill DRO' or 'Vertical Digital Scale' you will find more. Also if you search on YouTube about the quill DRO you will find some videos of fitting them to different milling machines.

Thanks Steran - After looking at it again today I can see that having a "mini" DRO on the quill might be helpful but putting one on the main column is probably not a priority for me. I never considered that a "quill DRO" would be a thing but of course it is!

Cheers....

I have an older HM45

The black cap lives in the back of the “I hardly ever use this stuff” drawer
Defeating safety devices is a bad idea, don’t do it…. My gaurd is in the same drawer as the cap..
The oil will be coming out the quill seal, relatively straight forward although a bit time consuming to replace.
Fitting a DRO on the head is pointless, all your adjustment is done using the quill. I have a DRO on mine, huge gain having it on the table, haven’t gotten around to fitting it to the quill yet, mostly because I ordered the wrong scale for the Z and haven’t been bothered ordering a smaller one. It’s not difficult but it does need some custom bracketwork to fit hold the scale onto the quill ring (or replace the factory quill ring if you’re really keen).

Hello Bammo.
I own one of these machines. When inspecting it from brand new about 3 years ago, I found that residual casting sand was [or was going to be] a major issue. Have a look with a good light down inside the main vertical column from the top & see if there are sheets of semi-bonded sand about to break off & fall down into the bevel gears that raise & lower the gearbox/head assembly. Very disappointing! (And don't lose the rectangular plastic cover at the top, falling down inside the column & base as I did a few weeks ago - it's a real bugger to extract.... Now secured with a piece of string).

I took the whole machine to pieces & gave it a damn good clean & inspection as a result. Glad I did. Learnt about the workings of the machine, too. I put a few photos & a description of that process on this forum at that time.

The oil leak is curious, because the gearbox casting wraps completely around the quill & is effectively separated from it, except right at the top.... unless the g/box was seriously overfilled with oil, which would be obvious at the oil level inspection window. There are 2 oil seals back to back at the top of the quill above the taper roller bearing. (One was damaged on mine). Plus it had casting sand in that area too. The oil could only self level near that point eventually but not all run out the bottom of the quill, surely.
The drain plug, behind the inspection plate underneath the g/box is a taper pipe-thread fitting; if this was seriously overtightened it could possibly crack the casting & be the source of the leak. It would be a good idea anyway to pull the top cover of the g/box off after removing the elec. motor & have a good look inside. There will be more casting sand evident in there, no doubt. Plus metal filings from the gears -I later fitted a magnet to the drain plug to catch those.
You don't really need to rotate the head to drain the oil per the manual; especially after you have spent ages 'tramming' it for accuracy. The g/box is a noisy thing especially at higher speeds. I have tried heavier oil in the g/box, but it doesn't seem to quieten it much.

I don't bother putting that 'witches hat' thingy back on top of the quill shaft any more, it's out of harms way for me, but I did make a large dia. plastic washer that sits on the top of the g/box & picks up on the two screws, just as an extra dust & debris seal above the top bearing.

The safety shield can be a bit of a pain, but it's there for a purpose. Though I have removed it once or twice when I don't want to raise the head halfway through a job. Handy for the 'off' function when flipped back though.

You'll find a decent downloadable manual for a very similar machine on the 'Grizzly' USA website, which is much more comprehensive than the local one.

Hope that helps a bit.
Halifax 614

If you are using your quill to do make the bulk of the movement instead of the Z-axis then a Quill DRO is going to be of a far greater benefit than a DRO scale on the Z-axis and if that's the case then save some dollars and just get a two axis DRO. Some quill dro's are supposedly complete kits, but I would think it vary from one Mill to another as to how 'complete' the kit is. Here's a link to Shars https://www.shars.com/dro-quill-kit-...-with-6-travel where I bought mine from years ago, but mine didn't come with the bracket and here's a link to video on installing a similar one https://www.youtube.com/watch?v=bemMMhaJfF4 . I've got a BM20E turret mill now and I'm going to fit mine to it's quill, I might even start working out the installation tomorrow.

I've got a HM-45.
I use the 'witches hat' just to keep the shaft clean and corrosion free. Yes, its a pain.....

I have the Grizzly version of the mill, bought roughly 10 years ago.

It has the breather tube but I remember seeing a sintered metal plug on one they bought for the tool grinding room (different brand, maybe Jet) where I worked, to cut Weldon (whistle) notches in some of the cutters. Neater looking installation and likely better at keeping bugs out.

The top/witches hat on mine has keyhole slots and takes a split second to twist and lift off and put back on. I keep it on all the time. If yours doesn't have keyhole slots then mod it so it does.

Mine has a quill shaft seal slow leak too but I have been loathe to pull it apart so I just add a bit of oil when the sight glass is down. Mine has a small drain plug at the bottom of the head close to the column for draining the oil so no head tilting gymnastics to drain it. Gears are loud as pointed out already.

I have seen one an acquaintance had that was converted to CNC and he pulled the gears and speed was via VFD controlled by the computer and an appropriate motor replacing the original.

Pete