Gallery, Projects and General > How to's
Asian 4x6 Band Saw V belt sizing
DaveH:
I decided to have a little 'chat' to my bandsaw. I wanted the saw blade to go at about 1000 ft/min, it looked at me for a couple of seconds and then fell over laughing on the floor. :coffee:
:beer:
DaveH
Pete W.:
--- Quote from: superc on April 09, 2014, 12:15:00 PM ---
SNIP
The big pulley's (bottom) central shaft (which a 10mm belt rests against) is 43mm in diameter.
SNIP
--- End quote ---
Also, I might have misunderstood this but surely a Vee-belt is supposed to contact only the sloping flanks of the pulleys - it shouldn't touch the bottom of the groove.
I can't remember where I read it (somewhere on Mad Modders) but I seem to remember someone complaining that his bandsaw had been assembled with the reduction gearbox reversed - that would give rise to excessive speed.
mattinker:
I suspect that someone substituted a higher RPM motor at some stage, maybe to use it to cut wood. These 4X6 bandesaws run 1700 rpm motors in the us on 60hertz AC current and 1500 RPM on 50herts European installations.
The difference between a 1/2" and the original 10mm belt would not give the huge speed differences encountered.
Regards, Matthew
philf:
superc,
I've just had a look at my saw (made by Clarke) and with a 50Hz 1,420rpm motor the three speeds given in the manual are 65, 95 & 165 ft/min. I checked the blade speed on the 65 ft/min setting with a Deumo mechanical tachometer and it's correct to within 1 ft/min.
Even with 3,800 rpm motor output this would only give 174, 254 & 441 ft/min. (By the way - 3,800 rpm doesn't sound right for an induction motor.)
Assuming your gearbox has the same ratio as everyone else's then I'm stumped. :scratch:
As Stuart pointed out 1,110 ft/min might be OK for wood but for sawing even aluminium with a HSS blade it's many times too fast.
Phil.
Manxmodder:
--- Quote from: Pete W. on April 10, 2014, 04:45:52 PM ---
--- Quote from: superc on April 09, 2014, 12:15:00 PM ---
SNIP
The big pulley's (bottom) central shaft (which a 10mm belt rests against) is 43mm in diameter.
SNIP
--- End quote ---
Also, I might have misunderstood this but surely a Vee-belt is supposed to contact only the sloping flanks of the pulleys - it shouldn't touch the bottom of the groove.
I can't remember where I read it (somewhere on Mad Modders) but I seem to remember someone complaining that his bandsaw had been assembled with the reduction gearbox reversed - that would give rise to excessive speed.
--- End quote ---
Hi there Pete,the reduction box on these saws is of the worm and wheel type so I can't imagine how that setup can be assembled to give any higher ratio,unlike if it was a pair of toothed gears.
You are absolutely correct in saying that a V belt shouldn't be contacting the well or bottom of the pulley,the angled faces of the belt should only be in contact with the angled faces of the sheave or pulley :thumbup: ...OZ.
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