delta DJ 15 jointer upgrade

[robert patrick]

I recently installed a Byrd cutterhead in my DJ-15. The 3/4 hp motor is not strong enough. I am going to upgrade to a 1 hp motor. The old motor was 1750 rpm, should I keep the same rpm and use the old pulleys. any help will be appreciated.

[ed morini]

https://www.mikestools.com/download/Delta-Jointer-Owners-manuals/37-150.pdf
It would appear from the manual that the original pulley set up yielded a cutter head rotation of 3450 rpm. I could find no pulley sizing to confirm that only the photos in the manual to go by.
If the new motor is 1725 rpm then the pulleys you have should work provided the shaft diameters are the same. You should calculate the actual cutter head rpm using the size ratio of your original setup and match that rpm. Looking in the manual the motor pulley and cutter head pulleys appear to be higher than 3450

[Bill Dufour]

Was this the factory motor? I would guess around 3,500 for the cutter head so a cheaper high speed motor would be used from the factory. A high speed motor will also save a few cents in shorter belt length and a smaller motor pulley.
I can see an easy $10 saved on each machine. Sell 10,000 machines a year. and save $100,000. That will pay the salary for the engineer who sourced the higher speed motor.
Bill D
Of course they may get a volumne discount on buying extra motors all to the same specs which cancels out any belt/pulley savings.

[Bill Dufour]

Some older jointers were direct drive. What rpm did the turn? Some direct drive bandsaws had odd low speed motors like 900 rpm.
BilL D

[Tom Bender]

Not a big increase in hp. Will it be enough? If you have to change pulleys and belts you might think about lowering the cutterhead rpm a little, maybe 20% to get more torque.
The more massive rotating head should still work well and cuts per inch will be unchanged, only the whole process will take 20% longer.

Note, when calculating pulley sizes use PD (pitch diameter).

[Richard Coers]

That's a 6" jointer right? 3/4 hp should be more than enough. Just how much material are you trying to remove in one pass? Making an extra pass would be a lot cheaper than a new motor!

[Warren Lake]

Jacks number is good 1 HP for every 4" of jointer. Look at any larger jointers and that is usually the case or more. The General 8" it came with a 1 1/2 HP and later changed it out to 2". Always depends on how you work. Place I got the General stuff originally offered 2 different HP's on a new machines.