Results 1 to 15 of 15
  1. #1
    Join Date
    May 2018
    Location
    Cairns, Qld.
    Posts
    70

    Default Inspection & rectifications on a new HM-46 Mill-Drill.

    This is a project from a little while back, but it might be found interesting...

    BTW I'm not intending to this post to be a rant in complaint against the supplier. As it says above - 'Metalwork Projects'. That's what it was & what I see it as now; a learning exercise.

    Back in June 2018 I decided to buy a hobby mill/drill after years of prevarication. Ordered a HM-46 via the Cairns agent of H & F Brisbane (1800 klms. away) early one week; fell off my motorcycle due a fuel spill & broke my left leg's tibia & fibula on the following Sunday; & got a phone call in the hospital on the Tuesday, "Your mill is here". Needless to say I wasn't caring that much at the time.
    However, my fellow Men's Shed members later managed to collect the damn thing on my box trailer, where it sat for the next 3 months at home whilst other matters took precedence.
    When I was eventually able to hop around a few months later, a team effort saw it taken off the trailer, on to a heavy duty rolling platform & into the under-house workshop. Knocked the packing case off & assembled the machine on to the stand. I had an engine crane previously purchased for this very purpose.
    However, later inspection with a torch & mirror revealed some issues.....

    Mill.Drill 1 at 10%.jpg In the trailer 006 at 40%.jpg Out of the box

    Below are the notes I made at that time....

    Late 2018. Post-receipt inspection showed that a large amount of casting sand remains inside the main vertical pillar of the machine & that some of this debris had already fallen into & is interfering with the operation of the vertical slide mechanism, lead screw & bevel gears.

    Dismantled the whole machine into separate sub-assemblies again to inspect & rectify as necessary.

    1) Main vertical column. A) Dismantled into component parts & inspected. Inside of main vertical casting has evidently had nil cleaning in the factory & is heavily contaminated throughout with casting sand. No paint or sealing inside, bare metal only. Dovetail ways on column casting show small voids in places that do not appear to affect operation. Main lead screw, both open thrust - bearings & bevel gears found to be contaminated with casting sand, which will affect their operation & longevity; grease & sand = grinding paste. Securing nut on lower end of lead screw assembly found not locking properly, allowing end float of whole assembly. Several shims found used to align bevel gear & lead screw castings with main casting. External square section of the raise & lower bevel gear shaft is 12mm across flats, whilst the inside of related & un-secured crank handle is 13 mm across flats; leading to a very sloppy fit.


    016 Inside of column as received @50%.jpg View inside the main column. Thick with sand & muck. (You can click & enlarge the photos I think).

    More later....
    Last edited by Halifax614; 13th Nov 2020 at 11:06 AM. Reason: Tidy up a bit

  2. #2
    Join Date
    Aug 2011
    Location
    Melbourne
    Posts
    4,779

    Default

    Hi Halifax,

    First up, terrible news to hear about your accident. Glad to hear you are on the mend.

    As to your mill. Unfortunately your experience is not at all unusual. My first mill, a mill very similar to yours (different supplier) was the same. I ended up totally stripping it down and degreasing and jet washing to clean it. Sand and grime everywhere.

    Simon

    Sent from my SM-G970F using Tapatalk
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  3. #3
    Join Date
    May 2011
    Location
    Murray Bridge S Aust.
    Age
    71
    Posts
    5,942

    Default

    As Simon mentioned, not an unusual situation. My Boss bought a 3metre X 5mm Pan Folder from H&F, it leaked Hydraulic fluid, originally from a fractured tank. This took 12 months of email/phone requests, to be repaired. It STILL leaks hydraulic fluid, but this time from the drain bung at the bottom of the tank. According to the repair electrician, the socket is of one type of thread, while the plug is of another, he applied a heap of thread tape in the hope of it sealing. Did it work, NO.
    When I was told what he'd purchased, I told him that their after sales service was virtually non existent. An Australian made equivalent was $16Kmore, I think there's been about $200 of oil bought for topping it up.
    Fortunately the floor slopes away, but oil is transferred about a 10m radius from the folder.
    Also, if you want a 90 degree fold, you have to go to 93-95 degrees, as it varies each time.
    Personally, I wouldn't buy anything from them.
    Kryn
    To grow old is mandatory, growing up is optional.

  4. #4
    Join Date
    May 2018
    Location
    Cairns, Qld.
    Posts
    70

    Default HM-46 Mill

    Thanks Simon & Kryn for your comments. When one lives away from the big smoke (Thankfully sometimes!) what can you do? If all the affordable new machinery is Chinese made; does it really make any difference who retails it here if the source quality is variable?
    I'd normally get down to Brisbane perhaps once or twice per year to see kids/grandkids; visiting H & F's big hangar of a place is like an Aladdin's cave for me! When I bought this machine back in 2018 it would have been a couple of years since I'd previously visited their building, so it was a choice between it & the larger of the Optimum machines, sort of 'sight unseen'. In retrospect, having re-visited since, I prefer this larger machine with its greater mass.
    I don't have the years left to hunt around for a good used machine (if they exist), & then it'd surely be on the other side of the continent!

    Anyway, this is what I did to remedy the issues that I found...

    B) Two days work with hand & rotary brushes, scraping, air blast etc. cleaning the inside of the main casting to remove both semi-loose crust-like deposits of casting sand debris that stretched from top to bottom. Once clean, this unit was painted inside with two coats of red etch-primer to seal the surface. Much completely un-necessary body filler removed from cover plates & related edges. Ways cleaned. Vertical lead - screw & bevel gear assembly dismantled & cleaned of all sand & grease residues. Main sealed ball bearing found secured to main shaft with heavy centre-punch marks. Why?? This bearing (6204) was replaced with a new item due evident internal roughness in operation. Lock-Tite used to refit. Serviceable after minor rectifications as required. Drilled & tapped a short 8mm hole in outer square end of raise/lower bevel gear shaft to take a permanent attach bolt for the crank handle, which was secured using 1mm packing shims to overcome the issues noted above. Re-assembled the vertical lead-screw, thrust bearings & bevel gear unit for proper operation. A thinned - down 16mm x 1.5 nyloc nut was fitted to lower end of vertical lead screw replacing the original tab washer & standard nut which had proved impossible to set & lock securely otherwise. A suitable plastic container was modified by cutting a hole in its base allowing it to be fitted inverted as a cover over the previously open bevel gear & thrust bearings assembly. Refitted this whole assembly to main base casting, using some original front cover shims as required for bevel gear clearances.


    017.jpg
    Inside column during cleaning 050 at 50%.jpg After clean & paint


    024.jpgBevel gear assembly 025.jpg Lead screw & gear assembly


    053.jpg Plastic bottle over the gear unit

    Halifax 614

  5. #5
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,439

    Default

    Hi H614,

    I would recheck the column and head for nodding when you come to refit the parts. You might find that you need to shim it to reduce the nod. I had to adjust mine with a couple of pieces of copy paper under the top pair of bolts. The only issue that I now have with my mill is that the tram varies with the height of the head. Its as though the column has a curve in it.
    Best Regards:
    Baron J.

  6. #6
    Join Date
    Aug 2010
    Location
    Toorloo Arm, VIC
    Age
    39
    Posts
    1,270

    Default

    Quote Originally Posted by BaronJ View Post
    Hi H614,

    I would recheck the column and head for nodding when you come to refit the parts. You might find that you need to shim it to reduce the nod. I had to adjust mine with a couple of pieces of copy paper under the top pair of bolts. The only issue that I now have with my mill is that the tram varies with the height of the head. Its as though the column has a curve in it.
    Going off the way the parts of my cross slide on the lathe were bowed when I blued them up, I'd almost put money on that being exactly the problem with your column (warped some time after being machined). If you've got a decent straight edge to blue it up with you could probably prove it without even pulling the mill apart - blueing one side on the flat way would probably show it up.

    Of course, then you'd be obliged to scrape it in to fix it.... best not to do that check then

  7. #7
    Join Date
    May 2018
    Location
    Cairns, Qld.
    Posts
    70

    Default HM46 Mill Rebuild

    Next were the base & saddles:- All this was good physical & mental therapy whilst hobbling about on the crook leg. Gotta do something useful....


    2) Main base, X, Y & Z - axis saddle castings:- Dismantled each into component parts; all cleaned & checked. Some loose sand evident. Much body filler & flaking standard off-white paint removed. Minimal lubrication evident on lead screws, guide nuts, thrust bearings & dovetail ways & gibs. Lead screw guide nuts were all unpainted & rusty. Other general minor corrosion treated. Sharp edges cleaned up. Minor fixes as required. Ways cleaned. Each item repainted with etch-primer where necessary to seal & rust-proof. Re-assembled each unit with plenty of lubrication on all wear points.

    020.jpg009.jpg005 (2).jpg014.jpg012.jpg047.jpg


    051.jpg



    3) Vertical column, base & X, Y & Z saddle assemblies all re-assembled on to stand & all moveable operations checked OK.

    055.jpg056.jpg065.jpg

    Gearbox next...More gritty drama
    H614

  8. #8
    Join Date
    Jul 2017
    Location
    Burleigh heads QLD
    Age
    29
    Posts
    114

    Default

    Quote Originally Posted by BaronJ View Post
    Hi H614,

    I would recheck the column and head for nodding when you come to refit the parts. You might find that you need to shim it to reduce the nod. I had to adjust mine with a couple of pieces of copy paper under the top pair of bolts. The only issue that I now have with my mill is that the tram varies with the height of the head. Its as though the column has a curve in it.
    I've found that due to the stacking error in the table ways and the saddle, the top of the table is often not co planar with the Y axis. You can shim the column to make the spindle perpendicular to the table but aside from the for mentioned error you must also remember that the spindle is also often not co planar with the Z axis, this means that as your Z axis position changes you get an Error in the true Y axis position and to a less extent the true X axis position. I hope that makes sense, these mills are a real head to scrape as you're dealing with so much factory error. I'd scrape a well built but worn knee mill over one of these any day of the week

  9. #9
    Join Date
    Aug 2011
    Location
    Melbourne
    Posts
    4,779

    Default

    Its looking much better. The red oxide is a nice touch. One thing, just be careful where and what you paint. Its not advisable to paint precision mating parts such as the column to base join. This can induce misalignment due to the thickness of the paint coating.

    Simon

    Sent from my SM-G970F using Tapatalk
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  10. #10
    Join Date
    May 2018
    Location
    Cairns, Qld.
    Posts
    70

    Default HM46 Mill Repairs etc.

    Should I look inside the gearbox? Be mad if I didn't.

    Notes at the time (2 years ago);-

    Electric motor, general external fittings & top cover removed. Inside found to be painted over about 90% of surface. Sand & metal debris are visible inside, mainly on bottom surface. Removed oil-tight cover above quill/drive shaft & found casting sand on grease adjacent to top taper roller bearing. Removed whole quill & drive shaft assembly, quill pinion cross shaft, return spring mechanism & fittings etc. Inside of vertical bored quill housing found contaminated with sand & dust. No sign of any original lubrication on sliding surfaces of quill or housing. Up/down feed & worm gear assembly removed from external r/h side of gearbox. No grease evident on any mating parts. Casting sand & corrosion evident inside large sleeve gear body. All parts have sand & dust evident & little protective paint inside main casting body.
    Removed HI/LO gear cluster for better access to gearbox internals. Interior of gearbox cleaned as best possible with kerosene, flushed contamination out as required. All internal bearings checked & considered serviceable. However, two stacked oil seals within top oil-tight housing surrounding drive quill found to be damaged ex-factory. Garter spring displaced 50% from one seal with wear witness marks on associated sleeve of top drive gear, & both seals showing abnormal wear & displacement. A new pair of common 45x35x7 oil seals were fitted, spaced to miss wear area on sleeve. (Originals were non-preferred sizes of 45x35x10 wide).

    Cleaned all other gearbox surfaces where sand & associated dust was previously evident. Etch-primed interior of oil-filled section to reseal completely, plus other dry interior surfaces where paint was previously thin or missing.
    Whole quill assembly dismantled to clean & inspect all parts. Top tapered roller bearing (30206) has casting sand sitting on top of original grease; this sand is collected every time quill is raised & lowered inside its housing. Thoroughly cleaned this bearing inner & outer; no sand had yet contaminated the races. Lower bearing (30207) cleaned & checked - no problems evident. No other issues evident with rest of parts associated with main drive shaft. Re-assembled unit with fresh moly grease & re-tensioned bearings to original previously marked settings.

    Refitted drive shaft assembly, locking shaft, cross pinion & return spring tensioner etc. to g/box body using moly lube. Refitted Hi/Lo gear cluster & oil-tight quill housing. Replaced top cover & checked gear change operation – all OK.

    Up/down quill feed components cleaned & inspected. Corrosion & sand removed as best possible from inside of large sleeve gear body & etch-primed inside to seal. Flaking paint & sand removed from other parts & main casting etch-primed internally. 2 worm gear bearings are OK. Refitted unit to main g/box body with moly lube to gears. Normal & fine feed operation checked OK.

    Gearbox re-filled with new sae 68 hydraulic oil. (2.5 litres approx.) & all other parts refitted. Manual operation rechecked OK. Gearbox refitted to vertical slide. Three new nyloc nuts replace original nuts & spring washers. Electric motor refitted & wired up. Mill started & run OK. All gearbox operations checked OK, though somewhat noisy.



    060.jpg
    Wear evident on sleeve gear due damaged oil seals

    072.jpg
    Casting sand on top quill bearing

    070.jpg Inside of g/box

    069.jpgVarious parts

    So of course that was time well spent giving the whole unit the 'once - over' because there were a few serious issues that needed dealing with. Disappointing that it should have been necessary in the first place.
    Halifax 614

  11. #11
    Join Date
    Dec 2013
    Age
    56
    Posts
    1,416

    Default

    I did this maticulously to a HM52 mill many years ago. Painting all the insides, but hopefully the outside soon to get rid of that horrible colour.

    Still going great these day, but didn't find the casting sand that you have.

    I did right up some threads/posts and took pictures, it gave me a good insight to the mill and it's workings and what needed addressing.
    I think every machine from China needs this.
    Using Tapatalk

  12. #12
    Join Date
    Aug 2011
    Location
    Melbourne
    Posts
    4,779

    Default

    Hi there,

    I took the gearbox apart when I bought mine too. Found similar issues. I didn't paint the inside but I did end up replacing all those cheap Chinese bearings with Japanese, Taiwanese bearings. After putting it back together the mill ran much smoother and quieter.

    Simon

    Sent from my SM-G970F using Tapatalk
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  13. #13
    Join Date
    May 2018
    Location
    Cairns, Qld.
    Posts
    70

    Default HM46 Mill

    Thanks Dave J & simonl for your comments. The gearbox is a bit of a noisy thing, looking very much like the basic but proven old technology inside my old BSA M20's motorcycle box. I replaced the standard watery-looking Iso 68 hydraulic oil with some heavier automotive g/box oil a while back to see what effect that would have. A bit quieter to my ear. I did make & fit a magnetic drain plug for the g/box at that time but I haven't pulled it out since.
    The machine seems to run quite well since the remedial work; I'm only doing light stuff on it atm (Odd jobs plus a model aircraft-type motor) whilst I learn how to use it properly.

    Cheers
    H614

  14. #14
    Join Date
    Dec 2013
    Age
    56
    Posts
    1,416

    Default

    Those heads are beefier than the heads on the HM52 mills as there is a lot more cast iron in them, the HM52 style of mill is available to us from China with that style of head or the Bridgeport style as I've looked in depth.
    Our quills are only held by 2 collars, where as yours is supported the whole length.

    This is something I'm rectifying by the way of a diesel engine sleeve I've recently bought, something that has been on my mind for 8-10 years but only just found a sleeve recently to fit.
    Many years ago I went to a reputable engine rebuilder who has now retired, but he couldn't find a sleeve to fit in his books.
    Some work ahead, lol
    Using Tapatalk

  15. #15
    Join Date
    May 2018
    Location
    Cairns, Qld.
    Posts
    70

    Default HM-46 mill rebuild

    Further to the mill rebuild, the only component that I didn't pull apart was the electric motor. It's running fine (fingers crossed).

    After fully re-assembling the machine, I went into the local Supacheap Auto looking for a suitable large new disc brake that might help with tramming the head, having read that this was a good method. There on a shelf was a 300mm dia. unit for $10, on special. Usually about $80... What luck! It made the subsequent work with a dti rotating off the spindle quite simple. After lots of tapping the head this way & that, I got the error down to a thou or so. Good enough for a learner on the machine. I did check the four corners of the main table at their extremes. +/-2 thou I think it was.

    A modification that I made more recently was to enlarge the cut-out & door in the steel box base unit. It was previously awkward fitting stuff inside, original 280W x 350H door cut-out increased to 340W x 450H. Made & fitted a new aluminium door with new hinges to suit, & refitted original latch:- much improved access.

    001 (2).jpg Larger door in base unit

    057.jpg As it was

    In February this year when I managed a visit to Brisbane, I went to H & F to have a look around. On the floor was another HM-46 mill, so I stuck my hand in the top of the column & sure enough, the same old casting sand problem was evident. Not good.
    If the man hours spent putting bog/body filler in totally un-necessary quantities & places on their machines was instead used on proper cleaning & assembly processes, all this frustration would be prevented.

    Now however, looking at the H & F website whilst the sale is on, I notice that they are listing an HM-46B, which appears to be different in detail from mine (HM-46) & very similar to the version I've seen listed on the American 'Grizzly' website. I.E. the Z handle on l/h side, not r/h, electrical controls different & no doubt other things I haven't yet noticed; so I'd venture that their supplier of that model has changed. I hope that it has better QC at the factory!
    Incidentally, a search of the above US website revealed excellent downloadable instruction manuals for very close relatives of my mill & even my older AL-300 lathe. Far better than comes with the machines as delivered here. Even if the yanks & us are separated by a common language....

    Halifax



Similar Threads

  1. Lathe inspection in Melbourne
    By robin2014nz in forum EBAY, GUMTREE, and other off forum sales sites
    Replies: 4
    Last Post: 28th Jun 2014, 07:48 PM
  2. Another Machine inspection required, near Newcastle
    By Ueee in forum METALWORK GENERAL
    Replies: 11
    Last Post: 9th Apr 2014, 02:45 PM
  3. Machine inspection again
    By Michael G in forum METALWORK GENERAL
    Replies: 17
    Last Post: 5th Apr 2014, 10:49 PM
  4. AL250G gearbox inspection for setting up.
    By Briangoldcoast in forum METALWORK GENERAL
    Replies: 10
    Last Post: 4th Jul 2013, 03:22 PM
  5. Selecting a small Mill / Mill/Drill
    By Wombat200 in forum METALWORK GENERAL
    Replies: 31
    Last Post: 15th Mar 2012, 10:58 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •