DIY winch line speed

davedj1 · Sep 15, 2017

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 · Sep 15, 2017

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 · Sep 15, 2017

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 · Sep 15, 2017

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 · Sep 15, 2017

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 · Sep 16, 2017

Have you tried Surplus Center for a sprocket?

Dave M7040 · Sep 16, 2017

davedj1 said:
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 · Sep 16, 2017

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

davedj1 · Sep 16, 2017

bigdeano said:
Have you tried Surplus Center for a sprocket?

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

davedj1 · Sep 16, 2017

Dave M7040 said:
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.

davedj1 · Sep 16, 2017

If you go here and open most any model parts diagram you can see the workings of the clutch/engagement. I plan to do something very similar.
Parts for Older Models | Parts | Parts | Tractor Mounted Winches - Farmiwinch.com

Citydude · Sep 16, 2017

davedj1 said:
If you go here and open most any model parts diagram you can see the workings of the clutch/engagement. I plan to do something very similar. Parts for Older Models | Parts | Parts | Tractor Mounted Winches - Farmiwinch.com

Good plan. Please keep us posted on your build!

davedj1 · Sep 17, 2017

I worked on some more calculations today. If I use a 4" pipe for the center of the drum and have 5 wraps of the .250 wire rope and use a 12 tooth drive sprocket and a 60 or 70 tooth driven sprocket I can get the ft/min speed down to pretty decent numbers. I calculated each wrap so obviously it will speed up as the cable winds in.
The 12/60 combo at 540 PTO rpm's will have a full spool speed of aprox. 129.6 ft/min. At 300 PTO rpm's it will be 71 ft/min
12/72 combo at 540 rpm's full spool speed of 106.5 ft/min and at 300 PTO rpm's it will have a full spool speed of 59 ft/min
I may do some more calcs tomorrow and use a 14 tooth drive and see how that pans out, thinking about it more I think 129/71 might be a little too slow. I am just going off what someone said above about the advertised speeds. I would like to keep it in that range.
thanks for the input so far

Rustyiron · Sep 18, 2017

If it were me, I'd make it a little slow, like your 71'/min. at a lower PTO speed giving you the ability to speed it up with engine rev's.
That's over a ft/sec, pretty fast (imho) unless your pulling in stump & rock free conditions.

Sawyer Rob · Sep 18, 2017

Once you get use to the winch, 75 is NOT too fast, I run mine faster than that all the time.

You have complete control of the clutch "right in your hands" and if you hit something, loosen up on the rope and all is well.

SR

kthompson · Sep 18, 2017

How does the diameter of the drum affect the life of the cable? I would assume smaller diameter will require more flexing of the cable and shorten it's life. Winches I ran used 1/2 to 5/8 cable and memory think those drums were at least 12 inches if not 14 to 16. These were on cranes and for that use 70 something feet per minute would be slow with no load. Then we were running four part line so that would have the hook block moving very slow.

davedj1 · Sep 19, 2017

All good info and thank you.
As far as the drum size and cable wear, I have no idea but I am looking forward to others input.
I know on Jeep winches the drum isn't very large and the cables (junk from the start) don't seem to have much issue if treated halfway decent.

Rustyiron · Sep 20, 2017

There are recommendations on the size (diameter) of a sheave to use for cable sizes to avoid damage, it would also (I think) apply to the drum size on a winch, but with each "wrap".......
One of these day's I'd like to try the synthetic rope. They say it is "non jamming" and it's obviously light weight. It is subject to abrasion damage and also expensive, but those that use it really like it.

davedj1 · Sep 24, 2017

I have synthetic rope on my Jeep 10K winch, I absolutely love it. You are right about the abrasion issues. I will tell you this, if you put a lot of pressure on the rope and spool it will get flat, it will cut you like dental floss! It can bind up too if you are not careful winching it in. Of course on the Jeep winch the spool is long and you almost NEVER winch straight on. I'm planning a leveler on the drum that will hopefully keep it from having a birds nest, I'm thinking a spring loaded piece of flat stock with a piece of pipe welded on the end to lay on the cable.