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tractor saw bench cutting speed
I am building a saw bench for firewood that runs off my tractor's PTO. What
is the ideal cutting speed for the blade, it is 29" in dia. My gearbox (on the saw bench) is 2:1 and I was going to use 1:1 for the gearbox to spindle sheaves. So basically my blade will be 1/2 the speed of my pto. Is this good or should I alter the sheaves ratio. |
habbi wrote: I am building a saw bench for firewood that runs off my tractor's PTO. What is the ideal cutting speed for the blade, it is 29" in dia. My gearbox (on the saw bench) is 2:1 and I was going to use 1:1 for the gearbox to spindle sheaves. So basically my blade will be 1/2 the speed of my pto. Is this good or should I alter the sheaves ratio. If the blade is new, I'd ask the manufacturer. Good blades are tensioned to run true at a predetermined speed. John Martin |
habbi wrote:
I am building a saw bench for firewood that runs off my tractor's PTO. What is the ideal cutting speed for the blade, it is 29" in dia. My gearbox (on the saw bench) is 2:1 and I was going to use 1:1 for the gearbox to spindle sheaves. So basically my blade will be 1/2 the speed of my pto. Is this good or should I alter the sheaves ratio. I run mine right off the PTO . I think it might be nicer if it was 50% faster . Twice as fast I think would be too much on mine . Trying to remember the blade D . Close to yours , if you want I will hike out and measure it . No way I would want mine running slower . Bearings now run just warm to the touch after hours of saw time . Luck Ken Cutt |
Which PTO speed do you have (540 or 1050)? Suspect that your shaft
speed will be too slow even with the higher speed PTO habbi wrote: I am building a saw bench for firewood that runs off my tractor's PTO. What is the ideal cutting speed for the blade, it is 29" in dia. My gearbox (on the saw bench) is 2:1 and I was going to use 1:1 for the gearbox to spindle sheaves. So basically my blade will be 1/2 the speed of my pto. Is this good or should I alter the sheaves ratio. |
Unless your saw is very thing (less than 0.125") the go for a rim speed
of about 6000-8000 ft/minute. (790 rpm - 1050 rpm). Bruce Lehmann TKT Engineering www.thinkerf.com |
I have both speeds, I tried it today and at the high pto speed and the 2 :1
gearbox it seemed slow. Tractor 2000, PTO ~1000 blade ~500rpm. "RoyJ" wrote in message nk.net... Which PTO speed do you have (540 or 1050)? Suspect that your shaft speed will be too slow even with the higher speed PTO habbi wrote: I am building a saw bench for firewood that runs off my tractor's PTO. What is the ideal cutting speed for the blade, it is 29" in dia. My gearbox (on the saw bench) is 2:1 and I was going to use 1:1 for the gearbox to spindle sheaves. So basically my blade will be 1/2 the speed of my pto. Is this good or should I alter the sheaves ratio. |
Thanks, I have it set-up for 500 rpm and it seems slow, I will change the
spindle sheave to a smaller one to give me a speed in your recommended range. "sawdoc" wrote in message oups.com... Unless your saw is very thing (less than 0.125") the go for a rim speed of about 6000-8000 ft/minute. (790 rpm - 1050 rpm). Bruce Lehmann TKT Engineering www.thinkerf.com |
habbi wrote:
Thanks, I have it set-up for 500 rpm and it seems slow, I will change the spindle sheave to a smaller one to give me a speed in your recommended range. "sawdoc" wrote in message oups.com... Unless your saw is very thing (less than 0.125") the go for a rim speed of about 6000-8000 ft/minute. (790 rpm - 1050 rpm). Bruce Lehmann TKT Engineering www.thinkerf.com Keep a watch on you bearing temps . Some old mandrels just will not handle high speed for long . You sure do not want to wipe one out with a 29 inch blade spinning right close to you . Luck Ken Cutt |
The bearings I have are old brass sleeve bearings with grease nipples, the
shaft is 1.5". The bearings are hefty and about 3" long. Do you think they will be fine? How true should they be to the shaft. when everything is loose the bearings spin freely on the shaft but once I tighten the bearing blocks down to the framework there is a bit of drag. This is do to the slight warping of the framework after welding. I can still easily turn the shaft with one hand on the shaft though. "Ken Cutt" wrote in message ... habbi wrote: Thanks, I have it set-up for 500 rpm and it seems slow, I will change the spindle sheave to a smaller one to give me a speed in your recommended range. "sawdoc" wrote in message oups.com... Unless your saw is very thing (less than 0.125") the go for a rim speed of about 6000-8000 ft/minute. (790 rpm - 1050 rpm). Bruce Lehmann TKT Engineering www.thinkerf.com Keep a watch on you bearing temps . Some old mandrels just will not handle high speed for long . You sure do not want to wipe one out with a 29 inch blade spinning right close to you . Luck Ken Cutt |
habbi wrote:
The bearings I have are old brass sleeve bearings with grease nipples, the shaft is 1.5". The bearings are hefty and about 3" long. Do you think they will be fine? How true should they be to the shaft. when everything is loose the bearings spin freely on the shaft but once I tighten the bearing blocks down to the framework there is a bit of drag. This is do to the slight warping of the framework after welding. I can still easily turn the shaft with one hand on the shaft though. "Ken Cutt" wrote in message ... habbi wrote: Thanks, I have it set-up for 500 rpm and it seems slow, I will change the spindle sheave to a smaller one to give me a speed in your recommended range. "sawdoc" wrote in message egroups.com... Unless your saw is very thing (less than 0.125") the go for a rim speed of about 6000-8000 ft/minute. (790 rpm - 1050 rpm). Bruce Lehmann TKT Engineering www.thinkerf.com Keep a watch on you bearing temps . Some old mandrels just will not handle high speed for long . You sure do not want to wipe one out with a 29 inch blade spinning right close to you . Luck Ken Cutt I go by feel on old style bearings . In fact that was what I saw my Grandfather do while I was growing up . Warm is safe , hot is not . Bronze bushings should be fine . Slight drag , well I would think that would accelerate wear to one side . Shim the blocks or clamp the frame enough to release the tension and weld a bar to hold it in its free position . Cutting with a buzz saw always feels too slow at the start and to fast towards the end . Also small stuff the saw seems too slow , big stuff too fast . Do a few hours of actual cutting and then see if you think it needs to spin faster . Or if the bearings are running hot . Likely you will not start out at the ideal speed but over the long haul you will be happy enough with the size of the pile . Luck Ken Cutt |
Ends up the slight drag is only when I tighten the belts. So bearings will
heat up if going too slow? I thought it would be the other way around. "Ken Cutt" wrote in message ... habbi wrote: The bearings I have are old brass sleeve bearings with grease nipples, the shaft is 1.5". The bearings are hefty and about 3" long. Do you think they will be fine? How true should they be to the shaft. when everything is loose the bearings spin freely on the shaft but once I tighten the bearing blocks down to the framework there is a bit of drag. This is do to the slight warping of the framework after welding. I can still easily turn the shaft with one hand on the shaft though. "Ken Cutt" wrote in message ... habbi wrote: Thanks, I have it set-up for 500 rpm and it seems slow, I will change the spindle sheave to a smaller one to give me a speed in your recommended range. "sawdoc" wrote in message egroups.com... Unless your saw is very thing (less than 0.125") the go for a rim speed of about 6000-8000 ft/minute. (790 rpm - 1050 rpm). Bruce Lehmann TKT Engineering www.thinkerf.com Keep a watch on you bearing temps . Some old mandrels just will not handle high speed for long . You sure do not want to wipe one out with a 29 inch blade spinning right close to you . Luck Ken Cutt I go by feel on old style bearings . In fact that was what I saw my Grandfather do while I was growing up . Warm is safe , hot is not . Bronze bushings should be fine . Slight drag , well I would think that would accelerate wear to one side . Shim the blocks or clamp the frame enough to release the tension and weld a bar to hold it in its free position . Cutting with a buzz saw always feels too slow at the start and to fast towards the end . Also small stuff the saw seems too slow , big stuff too fast . Do a few hours of actual cutting and then see if you think it needs to spin faster . Or if the bearings are running hot . Likely you will not start out at the ideal speed but over the long haul you will be happy enough with the size of the pile . Luck Ken Cutt |
habbi wrote:
Ends up the slight drag is only when I tighten the belts. So bearings will heat up if going too slow? I thought it would be the other way around. No the bearings will heat up if they are binding . Luck Ken Cutt |
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