# My next project.



## DAN_IN_MN (Feb 10, 2014)

Just found this on YouTube.  I heat with wood.  I've been wanting a winch.  I might have to take some design ideas from this one.

I knew there was a good reason I've been keeping all of those pulleys, sprockets, and gears!

[video=youtube;B10Io7MLp1Y]https://www.youtube.com/watch?v=B10Io7MLp1Y&amp;list=WL785A5515D63C753B[/video]


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## Bill Gruby (Feb 11, 2014)

That's cool. Go for it Bro.

 "Billy G"


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## chuckorlando (Feb 11, 2014)

Pretty slick there


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## RandyM (Feb 11, 2014)

Yup, very clever. Have fun.


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## brasssmanget (Feb 11, 2014)

wow - impressive stuff there - good luck making your own version. I'll have to tell my son I found a new use for his Stihl chainsaw and his SeaRay.


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## Kevinb71 (Feb 11, 2014)

That is very slick. Tons of uses for that other than logging. Pull your car/trauck up on the trailer etc. Simple yet very well executed. Good Luck!


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## Metalbender (Feb 18, 2014)

Have seen commercially made units like that a few years ago.


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## DAN_IN_MN (Feb 18, 2014)

Metalbender said:


> Have seen commercially made units like that a few years ago.



For $800.00 I can get one in a box.  I'm short $775.49! :rofl:

http://www.baileysonline.com/Tools-...ch/Winches/Lewis-Chainsaw-Winch-Model-400.axd



We'll see what junk I can use to put one together without it weighing a ton!


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## danwsmith7 (Feb 22, 2014)

Time for some Reverse engineering !!!:thumbsup:


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## DAN_IN_MN (Mar 3, 2014)

Looks like I'll be starting with a hand winch.  This looks to be the best deal that I can find so far.




http://www.amazon.com/gp/product/B00HRNECY8/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A3KP8KVFNCQXNQ

I have #35 roller chain.  Anyone have some sprockets laying around they'd want to part with?  I probably want to gear it down a bit.  

I'm thinking the saw is going to run around 10500 RPMs (Stihl 009L)  The winch is reduced to 8:1  

Anyone good with calculating reductions?  So, if I was to connect the saw directly to the winch the spool would be going how fast?  (I never fully grasped this with Algebra!)

Thanks for the input!


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## 12bolts (Mar 3, 2014)

Problem I see by gearing this down enough to not over rev the winch is the torque you will have multiplied so much that it will be extremely easy to over load the winch and cause some serious damage.
Just my 2c

Cheers Phil


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## Terrywerm (Mar 3, 2014)

Reductions are easy.  Here are some examples.

Drive gear has 12 teeth, driven gear has 48 teeth.  48 divided by 12 is 4, meaning that the reduction is 4:1    The driven gear will turn 1/4 the speed of the drive gear.

Another way to arrive at the same conclusion:   12 teeth divided by 48 teeth equals  .25  meaning that the driven gear will turn at 1/4 the speed of the drive gear.


Now, if you have multiple reduction ratios, let's say the first reduction is 4:1, the second reduction is 3:1, and there is a third reduction of 2.5:1   you can calculate the total reduction by multiplying all of the ratios as follows:
4 x 3 x 2.5  =  30  meaning the overall reduction is 30:1.    The final drive speed of the spool would be 1/30 the speed of the input to the first reduction.   If the engine speed was 6000 RPM,  and the overall reduction was 30:1, then the spool speed would be 200 RPM.

Inversely, if the engine puts out a torque of 100 in/lbs, the torque after reduction would be 30 times greater, or 3000 in/lbs which equals 250 ft/lbs


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## DAN_IN_MN (Mar 4, 2014)

terrywerm said:


> Reductions are easy.  Here are some examples.
> 
> Drive gear has 12 teeth, driven gear has 48 teeth.  48 divided by 12 is 4, meaning that the reduction is 4:1    The driven gear will turn 1/4 the speed of the drive gear.
> 
> ...




I'm thinking *the saw is going to run around 10500* RPMs (Stihl 009L) 


The question is, what gearing do I need in between these two?



The *winch is reduced to 8:1*  (what speed do I want the spool to turn? (60-80 ft/min cable speed))

http://www.lewiswinch.com/The_Lewis_Winch.html


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## 12bolts (Mar 4, 2014)

The quoted figures on the winch of 8:1 just refer to its own internal reduction. Crank the handle 8 times, the winch drum turns once. Ignoring frictional losses, basically if you can apply 50 ft/lbs with your arm then you will get 400 ft/lbs out.
If the winch handle spindle is designed to be turned at a maximum of 60 RPM, (thats pretty quick for your arm on a continuous basis) and by the look of it, just bushes for bearings, I would say thats optimistic.
If your saw is running at 10500 RPM and we want to reduce it to 60 RPM, thats 10500/60= 175. Total reduction you need is 175:1 At a input RPM of 10500 your gearbox will need some pretty good bearings.
Now if your chainsaw is 2HP it delivers (approx) 1100 foot lbs force/sec. Now with your winch at the end of 175:1 reduction gears you will have (approx) 192500 foot lbs force/sec!! Enough to tear the winch to pieces.

Cheers Phil


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## Terrywerm (Mar 4, 2014)

Phil, I think there is an error in your calculations there. I don't think there is a chain saw made that will put out 1100 ft/lbs of torque per second.  Not even the fabled V8 chainsaw of YouTube fame. To get that kind of torque we are talking about a 10 or 11 liter diesel engine.   Are you sure you didn't mean inch pounds??  I ran through the calculations, and come up with 2 HP converting over to 1100 in/lbs. In that case, we're talking 91.66 ft/lbs from the saw engine, and 16041 ft/lbs input at the winch.  Still enough to tear the winch apart!

Now, due to mechanical losses and other inefficiencies, I don't think we would see torque values quite that high, but they would still be significant! Additionally, there would be a lot of mechanical loss in power through a gearbox with a 175:1 reduction, not to mention that I don't know where in the world you find such a thing.


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## David S (Mar 4, 2014)

I think we have to work backwards.  The winch is rated at 2200 lb, so as long as the load doesn't exceed that rating then it really doesn't matter what the ultimate torque the engine and gear reduction can deliver.  Sure it may be capable of delivering more if you hook 4000 lb on to the winch, but then that is sort of like attaching a long bar to the winch handle and overloading the winch manually.  The estimate of 60 rpm at the winch handle is probably not too bad.  Now just come up with the 175:1 reduction and clutch.

David


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## DAN_IN_MN (Mar 4, 2014)

OKay, there's a video of this set up working.  The one in the video has a belt drive.  I wonder if the original designer put that in there for a slip function?

I chose the winch I did so I would have to do less gearing down.

I guess I'll just try some gearing.


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## DAN_IN_MN (Mar 4, 2014)

Found this forum with a guy designing a PTO powered winch.

http://www.tractorbynet.com/forums/build-yourself/195523-winch-calculations.html

I'll be honest, my eyes glaze over and my brain shuts down when I start trying to read/do calculations.  Probably a defence reflex.

Reading anohter forum, someone posted this link for surplus parts.  http://www.surpluscenter.com/  (I don't know about pricing or shipping costs.)


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## David S (Mar 4, 2014)

Dan,

If you can find an old 1/2" or 3/4" hand drill with an output around 500 rpm or less, you may be able to use that gear box as the first stages of your reduction.  Hand drill motors run in the 18,000 rpm range so the input would be ok with your chain saw.

David


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## DAN_IN_MN (Mar 4, 2014)

David S said:


> Dan,
> 
> If you can find an old 1/2" or 3/4" hand drill with an output around 500 rpm or less, you may be able to use that gear box as the first stages of your reduction.  Hand drill motors run in the 18,000 rpm range so the input would be ok with your chain saw.
> 
> David



That's a great idea!  I have another idea for a something chainsaw powered so that might help there too.


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## 12bolts (Mar 4, 2014)

terrywerm said:


> Phil, I think there is an error in your calculations there. .......



Terry,
I didnt check a printed reference book for that, but from http://en.wikipedia.org/wiki/Horsepower "quote" The mechanical horsepower, also known as imperial horsepower, of exactly 550 foot-pounds per second is approximately equivalent to 745.7 watts.
And from http://www.kylesconverter.com/power/horsepower-to-foot--pounds--force-per-second Enter your value of 2HP and in the solve box is the result 1100 ft lbs force/sec

cheers Phil


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## David S (Mar 4, 2014)

For sure we are mixing terms here.  Phil is talking power and quotes foot-lbs/ sec.  That is not torque that we are used to i.e. lb-ft.  Power is torque X rpm...so you can have hi rpm and small torque or low rpm and hi torque to get the same power.


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## 12bolts (Mar 4, 2014)

David S said:


> I think we have to work backwards. The winch is rated at 2200 lb, so as long as the load doesn't exceed that rating then it really doesn't matter what the ultimate torque the engine and gear reduction can deliver. Sure it may be capable of delivering more if you hook 4000 lb on to the winch, but then that is sort of like attaching a long bar to the winch handle and overloading the winch manually. The estimate of 60 rpm at the winch handle is probably not too bad. Now just come up with the 175:1 reduction and clutch.



David, you are assuming that the motor can deliver a nice smooth variable increase in torque. A 2 stroke motor has very little low down power. You need high revs to get anything out of them, and once the power curve comes on it rises dramatically. A heavy load might require substantial RPM just to get it moving. By the time that happens due to inertia you might have easily exceeded the SWL of the winch/cable. A prime consideration here is that it does matter what the ultimate torque delivered could be.
Attaching a long bar to the handle just makes it easier to turn regardless of the load. If you hook 4000 lbs on, its overloaded, whether you crank it by hand, extended lever or mechanical means
The reason we needed a 175:1 gearbox is because of the max RPM. If you want to work backwards then you need to know what torque is required to get your 2200 lbs out. From there you need to know at what RPM your power source will deliver the required torque, and then a gearbox to suit those RPM's.
But this still all ignores the fact that this winch is designed for human horsepower. The application of which is gradual and easily controlled, and can sense by feedback whether we are straining/struggling perhaps getting close to design limits. As I said in my first post, this is an accident waiting to happen....

Cheers Phil


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## DAN_IN_MN (Mar 4, 2014)

12bolts said:


> David, you are assuming that the motor can deliver a nice smooth variable increase in torque. A 2 stroke motor has very little low down power. You need high revs to get anything out of them, and once the power curve comes on it rises dramatically. A heavy load might require substantial RPM just to get it moving. By the time that happens due to inertia you might have easily exceeded the SWL of the winch/cable. A prime consideration here is that it does matter what the ultimate torque delivered could be.
> Attaching a long bar to the handle just makes it easier to turn regardless of the load. If you hook 4000 lbs on, its overloaded, whether you crank it by hand, extended lever or mechanical means
> The reason we needed a 175:1 gearbox is because of the max RPM. If you want to work backwards then you need to know what torque is required to get your 2200 lbs out. From there you need to know at what RPM your power source will deliver the required torque, and then a gearbox to suit those RPM's.
> But this still all ignores the fact that this winch is designed for human horsepower. The application of which is gradual and easily controlled, and can sense by feedback whether we are straining/struggling perhaps getting close to design limits. As I said in my first post, *this is an accident waiting to happen....*
> ...



Phil

Did you watch the video in my first post?

This isn't my first time around the block.  I will cautiously test/try things and then modify to make it work.  Many people will not try the things I do.


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## David S (Mar 4, 2014)

Phil I think we are on the same page actually.  I know you have to keep the rpms up on the small gas motor.  And do agree with your gear ratio suggestion.  The point that I was trying to make.. unsuccessfully.. was that one must work within the SWL of the winch.  In the video it could be that the "clutch" provided enough slip to get the load moving.


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## Terrywerm (Mar 5, 2014)

12bolts said:


> Terry,
> I didnt check a printed reference book for that, but from http://en.wikipedia.org/wiki/Horsepower "quote" The mechanical horsepower, also known as imperial horsepower, of exactly 550 foot-pounds per second is approximately equivalent to 745.7 watts.
> And from http://www.kylesconverter.com/power/horsepower-to-foot--pounds--force-per-second Enter your value of 2HP and in the solve box is the result 1100 ft lbs force/sec
> 
> cheers Phil



I was thinking about this all day today, and it was bugging me, you know how some things just sort of nag at you in the back of your mind??   Well, I thought it through, went through the math:  1 HP = 33000 pounds lifted one foot in one minute.   33000 divided by 60 seconds = 550.  So, one HP = 550 ft/lb per second, as you came up with. Your math was correct. (I won't tell that you cheated and used a converter) :donttell:      Anyway, I realized that something was amiss, however and finally figured it out. We were calculating direct force in ft/lbs, and rotary force or torque is measured in ft/lbs also, but the two measurements do not carry directly over from linear force to rotary force or vice versa if I remember correctly, thus the confusion.


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## jererp (Mar 5, 2014)

If you could get a power curve for your chainsaw engine, you would see that it develops a max torque at a certain RPM. That max torque number is what gets multiplied when you go through your gear reduction. 

I would concentrate on designing for RPM, and let the torque be what it may be.  As long as you don't hook it to an object that grossly overloads your original winch design load, you should be OK.  If you are worried about overloading, you could always add a shear pin for safety.


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## NEL957 (Mar 8, 2014)

Some one set up "the-little-winch-that-could" out of a lot of work and time. The only thing I would not want to be that close to that cable if it decided to turn loose. I have seen cables like that one almost cut a person in half. There is nothing like a cable under too much of load. If you were to build one the biggest thing I could recommend is to have some distance between you and that mochine. Just be carefull.
Nelson Collar


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## melsdad (Mar 11, 2014)

terrywerm said:


> Reductions are easy.  Here are some examples.
> 
> Drive gear has 12 teeth, driven gear has 48 teeth.  48 divided by 12 is 4, meaning that the reduction is 4:1    The driven gear will turn 1/4 the speed of the drive gear.
> 
> ...




Awesome information!!!! Thanks Applied!


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