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Thread: Macson surface grinder
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22nd Aug 2017, 07:01 PM #1Senior Member
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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?
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23rd Aug 2017, 09:35 PM #2Senior Member
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- Aug 2013
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- Melbourne
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Hi Alf
I have a Macson SG
The motor fitted to it is 0.5 HP 2850 RPM
Cheers
Peter
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24th Aug 2017, 09:06 PM #3
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.In essence your efforts may come to nought as the chucks will not function correctly
Apologies for the long reply, I hope at least the address is helpfulKind Regards
Peter
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25th Aug 2017, 09:17 AM #4Pink 10EE owner
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- Aug 2008
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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.
Gold, the colour of choice for the discerning person.
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7th Jan 2018, 02:42 PM #5Senior Member
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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
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21st Jan 2018, 02:35 PM #6Senior Member
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- Melbourne
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Hi Alf
Flat belt drive
motor pulley 3.5"
spindle pulley 2.8"
Pete
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24th Jan 2018, 10:35 AM #7Senior Member
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3rd Mar 2018, 08:04 PM #8Senior Member
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- Mar 2011
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Rebuilding a Macson surface grinder
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
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3rd Mar 2018, 08:13 PM #9Senior Member
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Rebuilding a Macson surface grinder
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3rd Mar 2018, 09:40 PM #10Golden Member
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- Dec 2011
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- Sydney
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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
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4th Mar 2018, 11:15 AM #11Senior Member
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- Aug 2013
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- Melbourne
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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
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4th Mar 2018, 06:23 PM #12Senior Member
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- Mar 2011
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- Taree NSW
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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
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4th Mar 2018, 09:20 PM #13Golden Member
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- Riddells Creek, Vic.
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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.
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4th Mar 2018, 09:49 PM #14Senior Member
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- Melbourne
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Hi Alf
As per techo1s description
IMG_1857.jpg
Pete
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5th Mar 2018, 03:33 PM #15Senior Member
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