Every one's Favorite Worm Drive Saw?

[PCFCACarpenter]

Re: Every one's Favorite Worm Drive Saw?

I bought the Bosch about 7 or 8 years ago before they had the quick connect cord. At that time the Bosch was 15 amp and the Skil was still 13amp. I think that might be changed now.
I customized mine with the old Skil Mag 77 base (The flat one). I wasn't real fond of the Bosch base but that combination works real well for me.
Two points about the comparison-
One if your arbor bent you probably had the blade too tight. You don't need to muscle down on the blade to get it tight. It should be tight enough to cut without slippage under normal pressure.
The second point is that when Skil and Bosch merged what improvements were made? Skil adopted everything that made the Bosch what it is. 15 amp motor, magnesium housing and the Bosch guard.
I'd say that the Bosch was a better saw a few years ago but now that Skil has copied every improvement they've made they're probably a similar product.

-Steve

[newman]

Re: Every one's Favorite Worm Drive Saw?

...One if your arbor bent you probably had the blade too tight. You don't need to muscle down on the blade to get it tight. It should be tight enough to cut without slippage under normal pressure.


-Steve

DING DING DING

I think we have a winner!

In fact my Bosch manual says to tighten the arbor bolt 1/8 of a turn past hand tight - DO NOT OVER-TIGHTEN!
Bosch calls it "Vari-torque clutch" - the friction between the blade and the arbor washer acts as a clutch to allow the blade to spin rather than kickback violently.

[PCFCACarpenter]

Re: Every one's Favorite Worm Drive Saw?

DING DING DING

I think we have a winner!

In fact my Bosch manual says to tighten the arbor bolt 1/8 of a turn past hand tight - DO NOT OVER-TIGHTEN!
Bosch calls it "Vari-torque clutch" - the friction between the blade and the arbor washer acts as a clutch to allow the blade to spin rather than kickback violently.

Thanks for the reinforcement and I think that applies to all saws not just Bosch. I have a Ridgid table saw in my garage that was given to me because something in the drive train blew out (I haven't yet had time to see what it was) and I think it's probably the same thing. Don't crank the arbor down too tight and adjust your feed rate to what the blade can cut.

Thanks,
Steve

[newman]

Re: Every one's Favorite Worm Drive Saw?

"VARI-TORQUE CLUTCH
This clutching action is provided by the friction
of the OUTER WASHER against the BLADE
and permits the blade shaft to turn when the
blade encounters excessive resistance. When
the BLADE STUD is properly tightened (as
described in No. 5 of Attaching The Blade), the
blade will slip when it encounters excessive
resistance, thus reducing saw’s tendency to
KICKBACK.
One setting may not be sufficient for cutting all
materials. If excessive blade slippage occurs,
tighten the blade stud a fraction of a turn more
(less than 1/8 turn). OVERTIGHTENING THE
BLADE STUD NULLIFIES THE EFFECTIVE-
NESS OF THE CLUTCH."

[gburnet]

Re: Every one's Favorite Worm Drive Saw?

"VARI-TORQUE CLUTCH
This clutching action is provided by the friction
of the OUTER WASHER against the BLADE
and permits the blade shaft to turn when the
blade encounters excessive resistance. When
the BLADE STUD is properly tightened (as
described in No. 5 of Attaching The Blade), the
blade will slip when it encounters excessive
resistance, thus reducing saw’s tendency to
KICKBACK.
One setting may not be sufficient for cutting all
materials. If excessive blade slippage occurs,
tighten the blade stud a fraction of a turn more
(less than 1/8 turn). OVERTIGHTENING THE
BLADE STUD NULLIFIES THE EFFECTIVE-
NESS OF THE CLUTCH."

How the heck is a blade that's mounted on a diamond arbor going to slip if it's in direct contact with the arbor?!

[gburnet]

Re: Every one's Favorite Worm Drive Saw?

Thanks for the reinforcement and I think that applies to all saws not just Bosch. I have a Ridgid table saw in my garage that was given to me because something in the drive train blew out (I haven't yet had time to see what it was) and I think it's probably the same thing. Don't crank the arbor down too tight and adjust your feed rate to what the blade can cut.

Thanks,
Steve

Perhaps you didn't completely understand my previous post, Steve. As I mentioned, it was a freak occurrence. A fall-off from a stud that was apparently the perfect size & shape to fit between the blade & upper housing became wedged between the two. I suspect that the fact it was in the shape of a wedge contributed to the damage, but it all happened so quickly that I can't say for sure. Nonetheless, you can rest assured that the bent arbor wasn't a simple matter of the blade being overtightened, but rather a result of a piece of material being drawn between the blade & the upper body of the saw, pushing the blade through the upper guard assembly.

[Tom Bainbridge]

Re: Every one's Favorite Worm Drive Saw?

newman and mark parlee, thank you for your suggestion and answer regarding 220v 50Hz motor

gburnet, the diamond is mounted on a sleeve that fits the arbor, the actual arbor is a cylinder

it's obvious once youve seen it

[newman]

Re: Every one's Favorite Worm Drive Saw?

How the heck is a blade that's mounted on a diamond arbor going to slip if it's in direct contact with the arbor?!

http://www.ereplacementparts.com/bos...1138_9621.html




look at the diagram - part # 23 and 24.

If tightened properly, the arbor flange is designed to allow the blade to slip rather than bind. I'm sure you overtightened.

[whiskytangofoxtrot]

Re: Every one's Favorite Worm Drive Saw?

I'm sure you overtightened.

I'm sure you meant to say, "the cutoff piece of wood that caused the blade to quickly and violently protrude through the upper guard assembly (locking up and thereby bending the arbor) is what "overtightened" it.

[newman]

Re: Every one's Favorite Worm Drive Saw?

I'm sure you meant to say, "the cutoff piece of wood that caused the blade to quickly and violently protrude through the upper guard assembly (locking up and thereby bending the arbor) is what "overtightened" it.

again, if it wasn't over-tightened, the blade would slip regardless of whether you hit a knot or a wedge of wood.

that's why the slip-clutch flange is there. I cut wet lumber all the time, and if the blade is dull or I push the saw too hard it slips - I don't "compensate" by over-torquing the blade nut.

[whiskytangofoxtrot]

Re: Every one's Favorite Worm Drive Saw?

again, if it wasn't over-tightened, the blade would slip regardless of whether you hit a knot or a wedge of wood.

Not necessarily :D

I'm sure that the possibility exists that the blade could deform in such a way (like deforming enough to protrude through the upper guard :) that it could add significantly more tension to a properly tightened slip-clutch-flange, thereby "overtightening" it enough to bend an arbor.

[newman]

Re: Every one's Favorite Worm Drive Saw?

Not necessarily :D

I'm sure that the possibility exists that the blade could deform in such a way (like deforming enough to protrude through the upper guard :) that it could add significantly more tension to a properly tightened slip-clutch-flange, thereby "overtightening" it enough to bend an arbor.

I suppose anything's possible. I've just seen too many guys torque the hell out of saw blade nuts, including miter saws.

[chuckwoodchuck]

Re: Every one's Favorite Worm Drive Saw?

I'd love to see a worm drive show down done. There are the new Milwaukee's, 2- Makita's availalbe Mag and regular, and the Bosch/Skil.

Would make for good reading.

[slimpickens]

Re: Every one's Favorite Worm Drive Saw?

I'd love to see a worm drive show down done. There are the new Milwaukee's, 2- Makita's availalbe Mag and regular, and the Bosch/Skil.

Would make for good reading.

Clearly we need Mr. Clark from Washington.

Starting at post #38, there is some seriously in-depth discussion regarding a few SCMS's and Dan ... well, let's say he doesn't leave much out.

http://forums.jlconline.com/forums/s...ad.php?t=47507

[kwoodhands]

Re: Every one's Favorite Worm Drive Saw?

I have a couple of the 8 1/4" skil worm drives. The older one was bought in 1964.My new model bought in 1990 I think. I'll probably sell both of them one of these days as I am retired.
mike