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  1. #1
    Join Date
    Mar 2011
    Location
    Taree NSW
    Posts
    47

    Default Macson surface grinder

    Picked up a Macson bench mounted surface grinder this weekend minus motor and faulty magnetic platen - can anyone one tell me what H.P. motor should be on it , I believe it is a 1440 but don't know what H.P - have searched the forum but can't find the address for Peter Tedesco who remagnetises these platens??
    I also got a valve refacing machine which I have no use for but think it could be converted to a tool & cutter grinder,
    has anyone any experience with this idea?

  2. #2
    Join Date
    Aug 2013
    Location
    Melbourne
    Posts
    176

    Default

    Hi Alf
    I have a Macson SG
    The motor fitted to it is 0.5 HP 2850 RPM
    Cheers
    Peter

  3. #3
    Join Date
    Mar 2004
    Location
    Carine WA
    Age
    68
    Posts
    75

    Default

    Quote Originally Posted by Alf Scotting View Post
    ...faulty magnetic platen -........ the address for Peter Tedesco who remagnetises these platens?
    Hi Alf

    This is the address I was provided to have my Eclipse brand repaired.

    There is a company below who has in the past been able to service and repair Eclipse Premier range chucks.
    We strongly recommend you contact them

    Magfield Manufacturing PTY Ltd
    5/4 Ovata Drive
    3043 Tullamarine
    Victoria
    Australia
    Tel 0061 (0) 3 9338 3655
    Fax 0061 (0) 9338 7222
    Contact Peter Tedesco

    Eclipse in the UK advised me (of course) that magnetic chucks cannot be "self repaired". Under threat of losing almost ALL magnetic holding power. To quote the response from Eclipse Magnetics UK, "dismantling the chuck without "demagnetisation" reduces the clamping force significantly, and is not recommended. After repair and assembly the chuck is "re-magnetised" to bring it back to full power.

    Being a little bit familiar with magnetics, from a good English education in physics in the early '60s, I didn't believe it! I could not see how the force could be reduced "significantly" by disassembly. So with this knowledge in hand, I decided to disassemble my chuck anyway (I also happened to have a second but MAIN mag chuck anyway) The short story is disassembly, clean, re-oil, seal all mating surfaces and reassembly produced no discernable difference in holding power!

    I did not use any calibrated measurement for my assessment of mag force, so my personal observation is quite subjective!

    With this success in mind, I chose to "bite the bullet" and repair the "MAIN" 400mm/18" mag chuck

    Keep in mind that both of these chucks were magnetically fully functional. The need for repair was the stiffness of the operating handle and the huge effort required to engage and disengage the magnets.

    The final result? Two very functional mag chucks the smaller of the two is the "normal" 300mm/12" size and the large chuck as noted above.

    Finally...

    If you attempt to do any dismantling of a magnetic chuck, be aware THEY ARE HARD TO DISASSEMBLE! The magnetic forces holding the components together are IMMENSE. Probably why the "professionals" demagnetise the unit first It does require the use of at least a VERY large crowbar pry-bar to get them apart - and this is to SLIDE them apart.

    On reassembly DO NOT PUT FINGERS BETWEEN COMPONENT PARTS - THERE IS A RISK OF SERIOUS INJURY!!!!!!!! I managed to create a scar at the base of my thumb, by manually trying (by hand) to push the top plate off the magnets. After pushing, pushing, pushing with great force, the plate finally slide away allowing my hand to smack into the (relatively) sharp edge of the body casting. I won't do that again PLEASE TAKE HEED!

    I used a pipe clamp (on the large mag chuck) attached to one end of the top plate in an attempt to rotate the top plate 90 - the galvanised pipe bent, the top didn't budge!

    As a very subjective test, using two 25mm square steel bars, I discovered that 10 square inches/64 sqcm could support 90+kg (me) placed approximately 12"/300mm from the end of the chuck!!!

    I have read/been told that keepers, bars that join the magnetic poles of magnets help maintain (and possibly improve) the magnetism. So I used metal plates across the poles during my mag chuck repairs.

    Eclipse in the UK no longer repair their OWN product!!!!!!!
    After repair and assembly the chuck is "re-magnetised" to bring it back to full power. These processes are now carried out if required by our factory in China. Sadly all the skill, equipment, and process documentation have been lost to us over time.
    ...another excerpt from Eclipse Magnetics UK
    In essence your efforts may come to nought as the chucks will not function correctly
    Well, they got that WRONG. They are unfamiliar with MY repair capabilities - especially when it come to items that "allegedly" can't be repaired!


    Apologies for the long reply, I hope at least the address is helpful
    Kind Regards

    Peter

  4. #4
    Join Date
    Aug 2008
    Location
    near Rockhampton
    Posts
    5,505

    Default

    Given the price of chinese chucks unless you live in Melbourne, it is simply not worth it to rezap old chucks that do not work.
    Light red, the colour of choice for the discerning man.

  5. #5
    Join Date
    Mar 2011
    Location
    Taree NSW
    Posts
    47

    Default

    Hi Petip,
    Thanks for post - I only have a pulley on the spindle - could you please advise dia. on yours of the spindle and motor ? I have picked up a 3/4 Horse for my SG and wish to make sure I get speeds right
    Cheers Alf

  6. #6
    Join Date
    Aug 2013
    Location
    Melbourne
    Posts
    176

    Default

    Hi Alf
    Flat belt drive
    motor pulley 3.5"
    spindle pulley 2.8"
    Pete

  7. #7
    Join Date
    Mar 2011
    Location
    Taree NSW
    Posts
    47

    Default

    Quote Originally Posted by Petip View Post
    Hi Alf
    Flat belt drive
    motor pulley 3.5"
    spindle pulley 2.8"
    Pete
    Thanks Pete,
    Mine has 'A' section 'V' pulleys - spindle shaft measured with a tape is approx. 70mm. - I am making a 3.5 dia. for the motor pulley
    Thanks for your help

  8. #8
    Join Date
    Mar 2011
    Location
    Taree NSW
    Posts
    47

    Default Rebuilding a Macson surface grinder

    Quote Originally Posted by Petip View Post
    Hi Alf
    Flat belt drive
    motor pulley 3.5"
    spindle pulley 2.8"
    Pete
    Hi Pete,
    Have just fired up my Macson with 'V' pulleys as advised (I got it with the spindle pulley as a 'V' so assumed it was standard) and when I fitted the grinding wheel it undid itself - nut is a RH thread and there are no markings on the home made wheel cover to suggest its correct rotation obviously with a RH thread retaining nut the wheel must rotate anticlockwise - supposed matched pair 'V' belt shows different tension on each belt although local belt supplier says there length is within 1mm. of each other? however to be fair I made the motor pulley.
    What is your grinding wheel rotation please



  9. #9
    Join Date
    Mar 2011
    Location
    Taree NSW
    Posts
    47

    Default Rebuilding a Macson surface grinder

    Quote Originally Posted by Petip View Post
    Hi Alf
    Flat belt drive
    motor pulley 3.5"
    spindle pulley 2.8"
    Pete
    Hi pete,
    have just fired up my Macson with 'V' pulleys as advised when I fitted the grinding wheel it undid the nut (RH thread)
    What thread is holding your wheel on , I assume it will be a LH thread and your wheel rotates anticlockwise?
    please advise



  10. #10
    Join Date
    Dec 2011
    Location
    Sydney
    Posts
    217

    Default

    Alf,
    This shows the standard wheel guard with arrow indicating direction of rotation.
    The threads on my example are left hand, on spindle nuts (both ends) and on the wheel carrier.
    Macson bench SG.jpg

    However, the image (below) of the spindle nose with wheel carrier in place (copied from C Groves 2012 thread on his Macson SG)
    seems to show a right hand thread securing the wheel to the carrier (function of the keyway is unclear) although the carrier is seen in other photos to be secured onto the spindle taper with a left hand thread.


    C Groves Macson _spindle_end.jpg

    Cheers,
    Bill

    edit - added sentences and extra image

  11. #11
    Join Date
    Aug 2013
    Location
    Melbourne
    Posts
    176

    Default

    Hi Alf
    As Bill said, wheel rotation is clockwise and retaining nut has a right hand thread. I was going to pull the wheel off to take a photo however I can't undo the nut at the moment!IMG_1855.jpg
    Between the nut and the wheel should be a washer with a tab that fits into the slot in the shaft. This will prevent the wheel unscrewing the nut.
    Pete

  12. #12
    Join Date
    Mar 2011
    Location
    Taree NSW
    Posts
    47

    Default

    Quote Originally Posted by Petip View Post
    Hi Alf
    As Bill said, wheel rotation is clockwise and retaining nut has a right hand thread. I was going to pull the wheel off to take a photo however I can't undo the nut at the moment!IMG_1855.jpg
    Between the nut and the wheel should be a washer with a tab that fits into the slot in the shaft. This will prevent the wheel unscrewing the nut.
    Pete
    Hi Pete
    There appears to be some variety between these surface grinders with some having wheel retaining nuts RH threaded and others LH thread - as mine has RH thread and a slotted shaft let's proceed this way however there isn't any register in the nut for the tab washer so when you get yours off would you mind sending me a photo of whatever feature there is on the nut to hold the tab washer please - obviously the tab would have to be bent after the nut is tightened
    thanks

  13. #13
    Join Date
    Sep 2008
    Location
    Riddells Creek, Vic.
    Posts
    424

    Default

    The tab on the washer fits into the groove in the spindle shaft preventing it and therefore the nut rotating, it does not get bent like a traditional tab washer.

  14. #14
    Join Date
    Aug 2013
    Location
    Melbourne
    Posts
    176

    Default

    Hi Alf
    As per techo1s description
    IMG_1857.jpg
    Pete

  15. #15
    Join Date
    Mar 2011
    Location
    Taree NSW
    Posts
    47

    Default Dimensions please

    Quote Originally Posted by Petip View Post
    Hi Alf
    As per techo1s description
    IMG_1857.jpg
    Pete
    Hi Pete,
    went everywhere this morning and cant buy a tab washer to suit grinder - only option as to have one laser cut - would you mind running a vernier over yours and giving me O.D. I.D and thickness so I can have one made?
    Thanks Alf

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