View Full Version : Massive buffing machine ID if anyone can help
GT Edgeworks
19th Apr 2019, 02:20 AM
I got this old girl at auction. Runs on my vfd on 240v. Does anyone know how old or have any details on her? I would like to restore it and clean it up do the bearings etc. If anyone can help with info that would be awesome!https://uploads.tapatalk-cdn.com/20190418/b1dd17df992e34fb9b2f90592fde8949.jpghttps://uploads.tapatalk-cdn.com/20190418/60f952d21474b090dce6e4286e550ab9.jpghttps://uploads.tapatalk-cdn.com/20190418/1baa5557520e6640d9fc8e19de7c106b.jpghttps://uploads.tapatalk-cdn.com/20190418/dae14cf6d2bac3801d84a6434922a60b.jpg
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BobL
19th Apr 2019, 10:42 AM
I'd be interested to know if you can get any more than 60Hz out of that vintage motor as all of the ones I have tried don't seem to like it much past about 55Hz.
The reason for the higher speeds is to get a much more efficient buffing action.
A 50Hz two pole motor running an 8" mop at 2850rpm is on the slow side for efficient buffing/polishing, so it takes a lot longer to do the job.
8" at 2850 rpm corresponds to about 5400 surface feet per minute (SFPM)
Here are some optimal speeds for buffing etc from https://www.schaffnermfg.com/engineers-speedchart/
378969
This table shows 5400 SFPM is on the slow side and most folks try to compensate for this by extra pressure, but, from the same website
Inadequate pressure gives NO buffing action.
Excess pressure will cause the buff wheel speed to be reduced and/or the buff to collapse and the operation to be LESS EFFICIENT or EVEN CAUSE A FIRE!
The state of the mops on that old girl suggest they have worn away so much resulting in much smaller diameter and hence much lower SFPM so then they have pushed too hard for too long.
The quickest way to increase the surface speed is to use larger mops, provided the buffer has the grunt to do this which your old girl should easily have.
EG at 2850rpm a 10" mop generates 7500 SFPM while a 12" mop will has 9000 SFPM!
The prices of large mops can be pretty exyy, but Ebay prices for a reasonable quality 12 x 1" thick mop out of the UK starts at around $45, $35 for the 10" mops ($50 at Hare and Forbes!) compared to about $30 for an 8". Larger mops last longer not just because of their size bu also because they are more efficient so you end up saving if you do a lot of buffing.
The mops of course do wear out so when a 10" mop reaches 8" in size the efficiency drops off and this is where a VFD comes in handy but only if the buffer motor is capable of responding appropriately. To get a 8" size mop back up into the efficient speed range requires about a 20% speed increase so the motor needs to be run at ~60Hz.
The magnetics of older motor will limit the speeds - as I said above none of the old motors have experimented with liked going much above 55Hz. One I tried was OK up to 60Hz but then started emitting electronic sounding squeeks and stuttering badly above that.
GT Edgeworks
19th Apr 2019, 11:52 AM
So I ran this up to 94hz as that's what I run my 2x72 grinder at. It didn't make any squeals just vibrated a fair bit. All food for thought tho. Thanks for your info
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BobL
19th Apr 2019, 12:42 PM
So I ran this up to 94hz . . .
That's pretty good. At those speeds I'll be interested to see how the bearings cope in time.
GT Edgeworks
19th Apr 2019, 12:51 PM
I am yet to see what kind of bearings it has in it. It appears to have oil galleries where the shafts exit the motor. So possibly non moving bearing surfaces
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YBAF
19th Apr 2019, 06:50 PM
...Does anyone know how old or have any details on her? I would like to restore it and clean it up do the bearings etc. If anyone can help with info that would be awesome!
If no one knows the brand I'd suggest a Trove search. https://trove.nla.gov.au/
- Take a guess... for dating, looks pre WW2. Bought at auction in Adelaide?... possibly manufactured or dealer supplied in Adelaide. Trove newspaper adverts search 1900 to 1939 based on Adelaide. Some adverts have pictures so yer might get lucky. Some adverts only have brand names, so do the brand name search looking for the manufacturer. There were many manufacturer related articles written back in the day. :cool:
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malb
19th Apr 2019, 11:47 PM
I had a similar unit at work 10 years ago, but possibly in a smaller size, mine was only a 2 horsepower unit that one is rated a fair way higher in power according to the manufacturers label. We primarily used the one we had with a belt on one side for basic linishing/deburing and occasionally with a buff on the other side for overflow buffing if the polishing room (4 of 7.5 -10HP) was busy. From memory, the old 2HP spindles were about 42mm diameter (imperial of course). At 2 HP it didn't have the guts that the larger units had when grinding or buffing, but it was ideal for what we wanted where it was located in the production line for basic linishing, and a lot quieter than the H&F 3HP linisher it replaced.
The wheel on your left tape has the appearance of being hard cotton wheel for running a belt that has been way overloaded with compound and used as a rough buff, and the right wheel appears to have been worn well below working limits for effective buffing and polishing unless you wish to work with quite small articles. As previously suggested in other posts you need a minimum 200-250mm buffing wheels to achieve decent surface speeds for efficient buffing, and you need to be able trim and comb the wheels regularly to maintain efficiency. If you want to go down the path of belt grinding with the unit, you need a rear turn around wheel and tower to support the other end of the belt, and a contact wheel in the 200-250mm range as well for maximum removal, though a smaller contact wheel would be OK for slower removal.
Also, keep separate belts and buffing wheels for each metal that you work with, as they retain particles of metal even after combing out and contaminate the work creaking odd effects over time, like rust spots in polished stainless or ali, spots that don't plate properly in mild steel, and an assortment of other difficult to trace back problems.
If at all possible set up a well enclosed polishing room, and do not store your various wheels, belts, compounds in the area. This will prevent the dust generated spreading around your workplace, and also prevent the dust contaminating wheels and belts. Our old polishing room with the 4 machines running 8hr/day generated a 44 gallon (appr 200L) drum of grunge every week from the dust collector and floor sweepings, so everything that you can do to isolate the machines from the rest of the shop is worthwhile.
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