Getting the most from my 3/4 hp motor
Moderators: HopefulSSer, admin
At the same speed, would knot a 10" blade at the tip turn slower, than a 9" one?
SS 500(09/1980), DC3300, jointer, bandsaw, belt sander, Strip Sander, drum sanders,molder, dado, biscuit joiner, universal lathe tool rest, Oneway talon chuck, router bits & chucks and a De Walt 735 planer,a #5,#6, block planes. ALL in a 100 square foot shop.
.
.
Bob
.
.
Bob
- JPG
- Platinum Member
- Posts: 34695
- Joined: Wed Dec 10, 2008 7:42 pm
- Location: Lexington, Ky (TAMECAT territory)
beeg wrote:At the same speed, would knot a 10" blade at the tip turn slower, than a 9" one?
FASTER by PI(3.14159...)
The circumference of the blade is PI times the diameter.
For 10" blade, = 10xPI. Each revolution = 31.4 in. At 3000RPM = 7854 ft/min = 131 FOOT per SECOND! = 192 miles / hour.
For 9" blade, = 9xPI. Each revolution = 28.3 in. At 3000RPM = 7069 ft/min = 118 FOOT per SECOND! = 173 miles / hour.
All these differ by 11%.
The torque required to exert the same force(tooth against piece being cut)will also differ by the same ratio.
╔═══╗
╟JPG ╢
╚═══╝
Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
╟JPG ╢
╚═══╝
Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
JPG is right again - Have to admit, I didn't think this (9" vs. 10" blade) conundrum through, until I read his posts. Yes the 10" blade will have a 11% faster tooth speed at a given RPM.2manband wrote:Maybe I'm over-simplifying this, but by switching to a smaller blade, aren't you just reducing the tooth velocity and increasing torque? Wouldn't slowing things down with the speed changer have the same effect?
With a 9" blade in order to achieve the same tooth speed, you would have to increase the speed of the machine. With the variable clutches working the way they do - you would actually have less torque on the quill than at the lower speed.
Don't ask me to figure how much torque changes with speed on the Mark V - I think applied torque would vary from speed to speed too much. All I know is maximum spindle torque is at the lower speeds.
Octogenarian's have an earned right to be a curmudgeon.
Chuck in Lancaster, CA
Chuck in Lancaster, CA
ONE HUNDRED NINETY TWO MILES PER HOUR!
I NEVER realized that it went that FAST.
I NEVER realized that it went that FAST.
![EEK! :eek:](./images/smilies/eek.gif)
SS 500(09/1980), DC3300, jointer, bandsaw, belt sander, Strip Sander, drum sanders,molder, dado, biscuit joiner, universal lathe tool rest, Oneway talon chuck, router bits & chucks and a De Walt 735 planer,a #5,#6, block planes. ALL in a 100 square foot shop.
.
.
Bob
.
.
Bob
- JPG
- Platinum Member
- Posts: 34695
- Joined: Wed Dec 10, 2008 7:42 pm
- Location: Lexington, Ky (TAMECAT territory)
Geez I hope my math is correct!!:Dbeeg wrote:ONE HUNDRED NINETY TWO MILES PER HOUR!
I NEVER realized that it went that FAST.![]()
╔═══╗
╟JPG ╢
╚═══╝
Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
╟JPG ╢
╚═══╝
Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
According to sawblade manufacturers, a saw that can operate on a 120V 15 amp circuit is "underpowered", and they recommend thin kerf blades. As I see it, the Shopsmith has two distinct advantages over all the others in this class; First, it is very easy to change blades in order to optimize performance, ie: rip, crosscut, plywood, laminate, ect. On most table saws, changing blades is a chore, undertaken only when absolutely necessary. Second, the variable speed feature makes it possible to reduce speed and gain cutting torque, enabling us to cut some pretty tough stock. I remember having to rip the entire 10 foot length of a rain soaked pressure treated 2" x 10". You have to reduce your feed rate accordingly, perhaps making a cut in 30 seconds instead of 15, which is no big deal. I should also mention that the variable speed feature makes it possible to eliminate saw blade burns on some types of sensitive woods.
Mention these features the next time someone trys to "put down" the Shopsmith because of the tilting table.
Mention these features the next time someone trys to "put down" the Shopsmith because of the tilting table.
Boy that does sound fast... I've heard it was around 100 mph for a normal table saw...
So let me give this a shot.
blade dia * PI * R/M = xxx"/min
10 *3.14*3400 = 106,760"/min
time 60 to convert to in/hour
60*106760=6405600 in/hour
/12 to get to feet /hour
6405600/12=533800 ft/hour
/5280 to get to miles/hour
533800/5280=101.09 miles/hour
Hmmm more or less what I've heard.
now for a 9" blade
9*3.14*3400 =96132"/min
5767920"/hour
480660ft/hr
91.03 miles/hour
Ed
So let me give this a shot.
blade dia * PI * R/M = xxx"/min
10 *3.14*3400 = 106,760"/min
time 60 to convert to in/hour
60*106760=6405600 in/hour
/12 to get to feet /hour
6405600/12=533800 ft/hour
/5280 to get to miles/hour
533800/5280=101.09 miles/hour
Hmmm more or less what I've heard.
now for a 9" blade
9*3.14*3400 =96132"/min
5767920"/hour
480660ft/hr
91.03 miles/hour
Ed
{Knight of the Shopsmith} [Hero's don't wear capes, they wear dog tags]
- JPG
- Platinum Member
- Posts: 34695
- Joined: Wed Dec 10, 2008 7:42 pm
- Location: Lexington, Ky (TAMECAT territory)
Sorry Guys. I apparently miskeyed 2580 instead of 5280 which put me off by about 2x. Ed is right on!:o
╔═══╗
╟JPG ╢
╚═══╝
Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
╟JPG ╢
╚═══╝
Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange