Jointer speed question

[Wild Turkey]

Byrd head on an 8" Jointer.

1750 rpm motor with 5" drive pulley, 2" driven pulley.

I calculate about 4300 rpm. Is that too slow?

Would a 6" pulley work better? Can't go smaller on top.

[Rick L]

Look up the specs on similar sized jointers.
https://d27ewrs9ow50op.cloudfront.net/sp...593_ds.pdf
Typically they use 3450 rpm motors. More torque. 5500 cutter head speed is common. Slower speeds just mean slower feeding. My old Oliver 16" with direct drive was 3450 rpm. You guys need to learn to search. Just new people asking old questions.

[thewizzard]

Wow, Wild Turkey looks like he's been here over 14 years and 20 thousand posts. Hardly a new person

Yea, its been asked before but then again so have 90% of every other question posed here

[Anthony W]

Rick L said:

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Look up the specs on similar sized jointers.
https://d27ewrs9ow50op.cloudfront.net/sp...593_ds.pdf
Typically they use 3450 rpm motors. More torque. 5500 cutter head speed is common. Slower speeds just mean slower feeding. My old Oliver 16" with direct drive was 3450 rpm. You guys need to learn to search. Just new people asking old questions.

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Old is relative on Woodnet, posts in this forum only persist for a year.

[®smpr_fi_mac®]

Rick L said:

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Look up the specs on similar sized jointers.
https://d27ewrs9ow50op.cloudfront.net/sp...593_ds.pdf
Typically they use 3450 rpm motors. More torque. 5500 cutter head speed is common. Slower speeds just mean slower feeding. My old Oliver 16" with direct drive was 3450 rpm. You guys need to learn to search. Just new people asking old questions.

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Says the new guy.

[MichaelMouse]

Pretty conventional. Keep the blades in good condition and no problems. Not sure how 3450 motor would give more torque, but it would be a bit more efficient with less motor heat loss. Not that most of us join more than four-five minutes at a time.

[TDKPE]

Wild Turkey said:

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Byrd head on an 8" Jointer.

1750 rpm motor with 5" drive pulley, 2" driven pulley.

I calculate about 4300 rpm. Is that too slow?

Would a 6" pulley work better? Can't go smaller on top.

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The pitch diameter of a sheave is normally about 0.15" smaller than the outside diameter made by the belt if wrapped half a turn or more (for measurement purposes), so assuming the belt rides flush with the OD of the sheaves, you have 4.85" driving 1.85", for a 2.62:1 speed increase, or just shy of 4600 rpm at full load. Whether that's too slow or not for your purposes, I couldn't say; just make sure you don't exceed the rated speed of the cutterhead.

6" driving 2" is about 5530 rpm at full load, again using 0.15" smaller PD than OD.

And a 2" driven sheave is pretty tiny. Use a cogged 'AX' type belt, as they bend over small sheaves better than L or A belts, and have higher power capacity (mitigated by the small sheave).

[Pirate]

I would use a 3450 motor. Raising speed with pulleys will decrease torque. Save the 1725 motor for a band saw or disc sander

[TDKPE]

Pirate said:

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I would use a 3450 motor. Raising speed with pulleys will decrease torque.

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But you're starting with twice the available torque, at half the shaft speed, for the same shaft hp.

[alnandy]

Here's an answer out of left field. A couple of months ago we finished restoring a 12" Northfield jointer that was built in the late 1920's (I verified this with Northfield). The same basic structure is still used in today's Northfields. My machine has Babbitt bearings; the motor, which is also original, is a 3 hp repulsion-induction motor, also with Babbitt bearings. The motor is housed in a 225 frame and weighs almost 150 lbs.
I asked Northfield about the recommended speed and they told me 3000 rpm max, to avoid overloading both motor and head bearings. I was skeptical, but it actually works; yes, the boards are fed much more slowly, but the torque is enormous; 12" hardwoods(such as hickory) don't come close to slowing this beast down. The machine runs so quietly it is dangerous, you don't know it's on. The surface finish isn't as good as a high speed motor, but the boards eventually go thru a planer and wide belt sander, so it isn't an issue.