I have a low end Grizzly table saw which has a arbor speed of 4700. I switched the motor and arbor pulleys so that the smaller one is now on the motor. The saw now seems to cut much smoother and has more power. I don't know what the arbor speed is now with the pulleys switched. Is there any reason I should not keep the lower speed arrangement?
-------------------------------- No.
Lew
Lew Hodgett wrote: ...
If you knew it originally, then the new speed is the ratio of the diameter changes between the original sizes and the new times that.
--
Ultimately you gained more power. If you are happy with it you are fine.
Dang...sorry for the reply wrong place...thought was/intended to be at the OP's posting. :(
--
I realize I inadvertently replied while reading Lew's response so try again...
As noted there, the speedup/slowdown between two shafts is proportional to the pulley diameters. To clarify the calculation you need, since you swapped pulleys, the ratio of speeds is the square of the smaller:larger diameter since it was a speedup of L/S and is now a slowdown of S/L.
Algebraically, the new speed is S/L/(L/S) --> S/L*S/L --> (S/L)^2
As a rough approximation example using easy numbers, if S = 3" and L =
4" and motor rpm were 3450, originally you had 4/3*3450 = 4600 rpm blade speed, roughly what you said is supposed to be.After you swap, it 3/4*3450 = 2600 (approx)
Note that 2600/4600 = .57 which is square of the 3/4 ratio of 0.75.
--
No he didn't. His saw has the same power as before - the HP of the motor. To gain more power you have to put a motor on which has higher HP rating. He did gain more torque at the blade, at the expense of lower rpm, and as you stated if he is happy ... Art
Err, no.
You have gained more torque, the power remains the same (ignoring transmission losses)
Speed is motor speed times the pulley size divided by the other pulley size.
Diameters of each pulley is good enough for government work. :-)
You can swap (in math) and calculate the old speed to check.
Mart> "Neal" wrote:
Higher speed gives a smoother finish. Lower speed helps your saw chew through harder lumber, like 4 x 4 cocobolo -- albeit at a lower feed rate. You can argue either way -- if your saw works better with the pulleys swapped, keep them swapped.
I would think you want your sawblade teeth moving within a certain range. A faster speed for less dense wood, and a slower speed for the harder woods.
Well thank you for pointing that out. But I think everyone will agree that the saw will be less likely to stall, similar to a saw with a higher hp motor.
Higher speed gives a smoother finish. Lower speed helps your saw chew through harder lumber, like 4 x 4 cocobolo -- albeit at a lower feed rate. You can argue either way -- if your saw works better with the pulleys swapped, keep them swapped.
You can effectively creat a smoother cut with a slower speed if you use a balde with more teeth. The slower you cut the wood the smoother the cut.
Which means less power to each tooth, defeating the purpose of slowing the blade to gain torque.
For ultrahard lumber like coke, I'd be more interested in getting it sawn than surface quality. A plane or a scraper will handle that detail quickly enough.
Which means less power to each tooth, defeating the purpose of slowing the blade to gain torque.
Actually you can simply cut at a slower rate, that accomplishes the same effect as a blade with more teeth.
For ultrahard lumber like coke, I'd be more interested in getting it sawn than surface quality. A plane or a scraper will handle that detail quickly enough.
coke?
Torque is a function of diameter, not a function of the number of teeth.
Maybe he's referring to Cocobolo.
Hide quoted text -
Torque is also a function of force. Diameter (radius, actually) is only half of the equation.
Right. Everyone screws the spelling. Better to use a shorthand name.
How could anyone screw up the spelling of Cocabollo?
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.