Wormdrive ?

[Grahamshed]

Didn't want to take another thread off topic by asking,
What is worm drive when related to saws and what is its significance ?

 

[MMUK]

Worm drive saws have a motor at 90* to the spindle rather than inline. The output shaft has the worm screw on it which drives the blade spindle. Worm drive saws run at slower speeds than inline drive saws and the general concensus is that they are more powerful and produce cleaner cuts. One downside is that they are considerably heavier and they are much more expensive. However, definitely worth it as they are much smoother running and cuts are much more precise.

 

[Grahamshed]

Thanks for that MMUK. Very well explained.

 

[carlb40]

Also it seems most require regular oil changes to keep the gearbox running sweet.

 

[CHJ]

Didn't want to take another thread off topic by asking,
What is worm drive when related to saws and what is its significance ?

It was referenced in the Nick Gibbs thread on saws.

http://commons.wikimedia.org/wiki/File:Worm_Gear.gif

 

[wallace]

Why would a saw with a worm gear cut better, I would have thought that a saw where the arbour is part of the motor would give a better result?

 

[MMUK]

Less chance of lateral movement. As an armature spins inside the stator, you get very slight lateral movement. Only minescule but it eventually leads to bearing wear and movement of the blade. With a worm drive, there should be absolutely zero lateral movement as the blade spindle is not connected to the armature. It should also be noted that a worm drive arrangement provides more torque and the blade won't snag if you use pushing pressure like an inline saw can (which also promotes bearing wear on inline types).

 

[Spindle]

Hi

Are there saws where the blade is directly mounted on the armature spindle? I thought they were mounted on driven arbors.

Regards Mick

 

[MMUK]

Hi

Are there saws where the blade is directly mounted on the armature spindle? I thought they were mounted on driven arbors.

Regards Mick

The arbors on inline saws are mounted to the armature on a slip joint or have a shaped socket with the armature shaft end shaped to match, they aren't gear driven.

If you look at this DeWalt exploded diagram you'll see that the arbor mounts onto the end of the armature shaft

See the difference on this Skil worm drive saw, it has a proper gearbox.

 

[Spindle]

Ahh I see - I was thinking of table saws #-o

 

[MMUK]

Ahh I see - I was thinking of table saws #-o

Table saws, as far as my experinece goes, are generally belt driven

 

[Grahamshed]

Learn something every day on here. I also would have thought the ordinary saw cut better. Now I know

Thanks for your replies everyone.

 

[zb1]

Inline saws vary. My C9U2 is inline with gearing between armature and drive shaft. I do like worm driven saws though as they usually tilt the other way and have very good visibility. Shame they are so difficult to get hold of in the UK.

 

[wallace]

(homer) I thought the topic was table saws

 

[Spindle]

If you look at this DeWalt exploded diagram you'll see that the arbor mounts onto the end of the armature shaft

Hi

I'm guessing that item 40 in the exploded diagram of the inline saw is a gearbox and hence the blade arbor is not directly connected to the armature

Had a quick look at my sons DeWalt saw earlier today and the above is backed up by the fact that the blade rotates in the opposite direction to the armature.

Regards Mick

 

[Myfordman]

If you look at this DeWalt exploded diagram you'll see that the arbor mounts onto the end of the armature shaft

Hi

I'm guessing that item 40 in the exploded diagram of the inline saw is a gearbox and hence the blade arbor is not directly connected to the armature

Had a quick look at my sons DeWalt saw earlier today and the above is backed up by the fact that the blade rotates in the opposite direction to the armature.

Regards Mick

Agreed, a universal motor has to turn at very high speed to develop any useful power and nearly always has to be geared down for practical use. Often the armature gear has to be so small to get a decent speed reduction ratio, it is cut into the shaft itself.