DIY winch line speed

[davedj1]

I am thinking about building a logging winch with a drive similar to a Farmi.
I will have a drive sprocket off the PTO of between 10 and 12 teeth, the driven sprocket on the cable drum will be 60 tooth. The drum diameter is 6" well casing that will be no more than 5" long.
Assuming I will be running at PTO speed of 540 rpm's I take the final gear reduction of 60/10 =6, then divide 540 by 6 = 90, the circumference of the drum is 18.8" so 90x18.8=1692 then divide by 12=141 which is feet per minute.
I understand this will all change based on wraps on the drum, whether I use a 10 or 12 tooth sprocket and whether or not I will be at full PTO speed (most likely not).
Questions:
1) Is my math correct?
2) does that speed sound reasonable?
3) will .250 wire rope be sufficient? ( I have a 500' spool of it) 7x19 ,4000 psi strength. (I think I already know the answer to this one but I have used about 100' of it to yard logs up over a bank via a snatch block hooked to a tree and using my truck to pull them with and had no issues)
FYI: tractor is a Ford 3000 2wd 3 cyl gas with ag tires and a select o speed transmission.
Trees are not that big (6"-18") and I can cut them to any length that works best.
Thanks for the feedback and help in advance
David

 

[Sawyer Rob]

What are you going to use for a clutch on it?? I hope NOT the tractors clutch...

How about a brake??

I'd want bigger cable than quarter inch on that winch!

SR

 

[davedj1]

Hi Rob, it will have clutch disks similar to the Farmi, it will have cogs for the brake.
I may have to break down and buy some heavier cable.

 

[CobyRupert]

Your math seems right.

Wallenstein winch specifications say that their cable runs at 75-175 ft/min at 540 rpm.

Almost nobody runs their winch at 540 rpm. I rarely run over 300 rpm.

I presume 75 ft/min is with no wraps on drum, 175 ft/min is with 165' of cable on drum (at 540 rpm).

If 75 ft/min is the "base" speed (without cable wraps), your gearing seems high.

I'm surprised to see that that the range "based on wraps on the drum", is so large (a factor of 2.33).

 

[davedj1]

Thank you for the input. If I slow the PTO speed down to around 300 I get a speed of 78.3333 f/m
I would go with a larger driven sprocket but I can't seem to find one for sale at a reasonable price.
"I'm surprised to see that that the range "based on wraps on the drum", is so large (a factor of 2.33)." I did the math for the well casing at 6" it is 18.8" around so I guess with a larger cable for each wrap you are adding quite a bit more length.
I just calculated 4 wraps of .375 diameter cable and it will use 28.27 inches per wrap, calculate all that out at 300 PTO speed and I get 117.7 ft/min

Maybe some 5" pipe? I don't mind getting a larger sprocket but I can't seem to locate what I want.

 

[bigdeano]

Have you tried Surplus Center for a sprocket?

 

[Dave M7040]

Thank you for the input. If I slow the PTO speed down to around 300 I get a speed of 78.3333 f/m
I would go with a larger driven sprocket but I can't seem to find one for sale at a reasonable price.
"I'm surprised to see that that the range "based on wraps on the drum", is so large (a factor of 2.33)." I did the math for the well casing at 6" it is 18.8" around so I guess with a larger cable for each wrap you are adding quite a bit more length.
I just calculated 4 wraps of .375 diameter cable and it will use 28.27 inches per wrap, calculate all that out at 300 PTO speed and I get 117.7 ft/min

Maybe some 5" pipe? I don't mind getting a larger sprocket but I can't seem to locate what I want.

What sort of line pull are you expecting to get.

The well casing at 6"+seems like a very large winch drum diameter to me but again I don't know logging winches just military truck winches from a Volvo C303 I had in the 1970's.

Dave M7040

 

[Citydude]

How are you going to engage and disengage the drive sprockets?

 

[davedj1]

Have you tried Surplus Center for a sprocket?

Yes I have, they don't have anything that large that I found.

 

[davedj1]

What sort of line pull are you expecting to get.

The well casing at 6"+seems like a very large winch drum diameter to me but again I don't know logging winches just military truck winches from a Volvo C303 I had in the 1970's.

Dave M7040

I have no idea what line speed to expect. I suppose I should go to a dealer and at least look at one in person, it may shed some light on things.
The only reason I thought of the 6" well casing is because I have some of it. I may just calculate everything out at 4" and see where that leads.