# Skill Shd77 circular saw



## beerdog (Dec 10, 2008)

Anyone know what the difference is between the Skill Shd77 and the hd77 worm drive saw?


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## PaliBob (Jun 11, 2008)

Here is a Link to the SHD
http://www.amazon.com/exec/obidos/ASIN/B000P7MAEM/ref=nosim/coffeeresearch48193-20

and the magnesium SHD77M
http://www.amazon.com/exec/obidos/ASIN/B000P7MAGA/ref=nosim/coffeeresearch6053-20

If you are looking for more information call Skil Customer service to get the information direct: http://www.skiltools.com/en/AllTools/Category/Product/default.html?pid=SHD77&cid=192170


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## beerdog (Dec 10, 2008)

Thanks. I looked at the specs. all I can see is that the SHD is a 15AMP versus the DH77's 13amps. When I read different websites everyone recommends the HD77. A hardware store has the SHD77 on sale for only $150. I am contemplating buying one unless someone has any info on if it is better to just stick with the HD77.


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## Yoyizit (Jul 11, 2008)

beerdog said:


> Thanks. I looked at the specs. all I can see is that the SHD is a 15AMP versus the DH77's 13amps. When I read different websites everyone recommends the HD77. A hardware store has the SHD77 on sale for only $150. I am contemplating buying one unless someone has any info on if it is better to just stick with the HD77.


If your power out per dollar is higher with the SHD then I wonder if they traded off reliability for this increased power.


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## micromind (Mar 9, 2008)

Before I bought a 15 amp saw vs. a 13 amp one, I'd need to see spec.s, namely locked-rotor current. 

A basic Skil 77 draws about 6 amps no-load, about 12 amps cutting 1/2" plywood, about 25 amps ripping a 2X, and about 90 amps while starting. This starting surge will trip a breaker occasionally. 

If the 15 amp motor draws even more current while starting, it'll trip more breakers more often. 

This may be a case where more is not better. 

Rob


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## beerdog (Dec 10, 2008)

I called Skil. They said the SHD77 is the latest upgraded model. The only difference is it has newer, stronger moter. Hence the 15 amps. I guess i will buy it and see how it works.

I never realized how nice these are untill I borrowed my friends. It just cut so smooth and effortlessly. I have seen some people complain about the weight, but that seemed to stabalize it and make it easier to push it through the wood.


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## Yoyizit (Jul 11, 2008)

beerdog said:


> I called Skil. They said . . .


Since they will talk to you, ask how far above ambient temp. the motor is supposed to get, under what usage (duty cycle). 
If you can find the same info under the same conditions for the other saw, motor lifetime halves for each ~10C rise above ambient temp.. You can figure relative reliability.

The 15A motor should give you (15A/13A)^2 = 1.33 = 33% higher rise above ambient, assuming the motors in each saw are equally efficient, have equal design lifetimes, and each saw dissipates the heat equally [thermal resistance depends on surface area]. 

If they don't know what you're getting at they might actually give you useful info.


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## PaliBob (Jun 11, 2008)

beerdog said:


> .........I never realized how nice these are untill I borrowed my friends......


 Here in the West Worm drives seem to be much more popular than in the East. 

I just saw this killer deal on JLC for a 15 amp Bosch for $136 @ Amazon
(Limited qty)

http://www.amazon.com/Bosch-1677M-4...sr_1_385?ie=UTF8&s=hi&qid=1240612359&sr=1-385


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## Yoyizit (Jul 11, 2008)

PaliBob said:


> Worm drives


Maybe the woods found in the west take higher torque to cut effectively?


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## PaliBob (Jun 11, 2008)

*Reason worm-drive saws were invented*

Yoyisit, You piqued my curiosity. Google found a real jewel on _asktooltalk.com_ that uncovered *worm-drive* and *sidewinder* history with some real surprises


http://www.asktooltalk.com/articles/toolhistory/divide.php


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## Yoyizit (Jul 11, 2008)

PaliBob said:


> Yoyisit, You piqued my curiosity. Google found a real jewel on _asktooltalk.com_ that uncovered *worm-drive* and *sidewinder* history with some real surprises
> 
> 
> http://www.asktooltalk.com/articles/toolhistory/divide.php


"it was in the locations of the manufacturers and what line the distributors were carrying and not personal preference."
So, there is a correlation but the causality chain is a little more roundabout.

"A unit in 1941 cost $105; today, the saw is about $130." 
It should cost $800 today, with inflation.


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## 7echo (Aug 24, 2008)

Around here most everyone uses a side winder. It is amazing, and sometimes scary, what a good framing guy can do with one. I have always heard the worm drives are west coast tools, though I know a few guys that have them. I will read the article, thanks Pali.


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