Jointer update: Which pulley combination is best?

[stryped]

Well, went to Tractor supply. All I could come up with is a 6 inch pulley for the motor and a 2 inch pulley for the jointer. So I currently have a 5 inch pulley, six inch pulley for the motor and a 2 inch pulley and a 2.5 inch pulley for the jointer.

So, My options are a 6 inch pulley on the motor and the stock 2.5 inch pulley on the jointer for a total of 4176 rpm.

6 inch pulley on motor with new 2 inch pully on the jointer for 5220 rpm.

5 inch pulley that came with the motor and new 2 inch pulley on the jointer for 4350 rpm.

I think my manual said to shoot for 4400 rpm. I know the new model jointers turn at 5000 though.

Here is a link to that page in my manual that talks about required speed:

one should I use? Also, I dont have a guard ont he jointer. (Yet) What is the risk of one of those knives flying out?

[Chuck Taylor]

Once you're *sure* of what your manual said, come on back and ask again.

[alexy]

Or live on the wild side and just do what it says in the manual without asking for confirmation here!

[stryped]

[Doug Miller]

Probably not -- but 5220, as you said in your earlier post, is not just "a little" faster. That's almost 20% faster. There is a possibility that the knives will come out, if you spin the cutterhead that much faster than it was designed for. Maybe only a small possibility, but a possibility just the same.

I apoligize in advance for being blunt almost to the point of rudeness, but I have to say this:

God gave you a brain.

Use it.

The manual calls for 4400. Your choices, according to your earlier post, are

4176, 4350, and 5220.

This does *not* require a whole lot of thought to figure out.

[Clint]

I don't think the guard is there to keep the knives from flying out and hurting you; it's there to try to keep you from doing something silly and sticking a consumable item (i.e. finger) in the sharp whirly danger area.

Given the number (and type) of questions you've been posting over the last week or two, I'd advise getting a guard in place. Soon. Like, before you hook power up to the thing.

As far as your question goes, I don't understand why you're even asking it. The link you posted says "For best results the jointer should be operated at approximately 4400 R.P.M." To me, 4350 is approximately 4400, and is obviously your closest match. 5220 is not, and you'll be exceeding their recommendation by about 20%. Considering the thing is old and in unknown state, it seems foolish to me to consider doing that just because the modern ones run faster. This isn't a modern jointer, and it didn't magically become better built over the last few years.

BTW, you did confirm that the motor attached to your jointer is a 1725 rpm motor, right? The manual link you posted suggests a 3450 rpm motor but since the jointer appears to originally come without a motor, there's no telling what's there without looking.

Clint

[stryped]

The motor is a 1740 rpm according to the plate.

I am ask> I don't think the guard is there to keep the knives from flying out and

[Clint]

Running faster means more cuts per second, which should mean a smoother surface on the wood. But spinning things at higher than recommended rate is dangerous. Centrifigual force, overheated bearings, etc. And since the

5220 rpm wasn't just a little faster, I sure wouldn't recommend it. If it was the other way around, with a choice of 3600 rpm (800 less) or 4450, I'd go with the 4450 and not worry about that.

As far as the guard goes, running without it is just seems silly, regardless of what it looks like. Maybe if you had years of experience with them, and knew the danger areas, it might be different. And metal, plastic, or wood will all work just as well, I'd imagine. If it makes it look better, make it out of MDF and paint it the same color as the jointer. Put some racing stripes on it if you want better performance, and away you go. The nice thing about a wood one is if you're off on the dimensions at all, and the guard gets nicked by a blade, you won't damage your new blades.

Clint

[Paul D]

The answer to your question

Your questions have been answered at least twice in here Your questions have been answered at least twice in rec.crafts.metalworking Your questions heve been answered in the manual which you supplied a link to ...

Just incase you missed it from the manual SPEED For BEST results the jointer should be operated at APPROXIMATELY 4400 RPM. Satisfactory operating power and speed may be attained by using a 1/2 horse power 3450RPM motor equipped with a 2 1/2" diameter pulley.

Half the motor speed = twice the size pulley ... ie: 5"

[stryped]

[Mike Marlow]

What does it matter? It's all a matter of ratios.

[Doug Miller]

It doesn't matter. You know what sizes of pulleys you have to choose from, what speeds they will produce at the cutterhead, and what speed you're supposed to have at the cutterhead. That's all you need in order to figure out which pulleys to use.

[Wilson]

[bridgerfafc]

faster cuts better sometimes; as long as the blades are nice and sharp... if they are getting even just a little dull faster will burn the wood.

a plywood guard is a good start for any homemade guard. first, it gets something there right away and for cheap- so you're covered for the immediate. second, it lets you run the thing for a while before you invest the time and cash making a metal one. once you've figured out what works or doesn't, go ahead and make a final version from metal, lexan, nice hardwood or what have you.