PTO Capstan Winch (from scratch)

TimberHole · Mar 7, 2018

I have multiple logs and trees I need to skid out of s slough. I have a new 7,500 lb electric winch that I bought after someone posted a link on this site a few months back. It has 55' of steel cable and a 30' control cable that would keep me out of the line of fire. With several 50' chokers I could extend the reach. I was thinking about a 3 point mounted heavy plate to anchor the tractor and a short mast with a sheave to elevate the line pull. Anyone have an opinion about my poor mans plan?

bcp · Mar 7, 2018

Electric winches are very slow if used near their capacity. Slow line speed for a minute or so, then a long cooling time.

Here is a HF 9000lb winch. Note the duty cycle and line speed (in red rectangles). It can run for about a minute at 8000lb, pulling about 6 feet, then a 15 minute cooling off period. That's around 25 ft per hour. At about 1/4 that load you will double your line speed, and reduce cooling time, but still slow.

Bruce

k0ua · Mar 7, 2018

Not to mention big electric winches draw huge amounts of current, and most Tractor alternators are really very small. Usually no more than 50 amps. Now where near what a large winch can draw. So hope your battery is in good shape.

TimberHole · Mar 7, 2018

Thanks bcp......I didn't have any idea that the duty cycle was that low. Glad I asked! I'd say my design concept is a total bust! I guess I'll keep thinking.

flingwing1969 · Mar 7, 2018

bcp said:
Electric winches are very slow if used near their capacity. Slow line speed for a minute or so, then a long cooling time. At about 1/4 that load you will double your line speed, and reduce cooling time, but still slow.

Exactly.

flingwing1969 · Mar 7, 2018

k0ua said:
Not to mention big electric winches draw huge amounts of current, and most Tractor alternators are really very small. Usually no more than 50 amps. Now where near what a large winch can draw. So hope your battery is in good shape.

You can replace the alternator there are a number of them that I've found that work and will give you 200 amps or so. But that won't improve your duty cycle or pull speed.

flingwing1969 · Mar 7, 2018

TimberHole said:
It has 55' of steel cable and a 30' control cable that would keep me out of the line of fire.

If you use a snatch block you will be pulling 90 degrees or so from the direct load pull, as well as doubling your pull. Throw a heavy blanket over the cable on the tractor side and it will dampen the snap back in the event of a cable failure.

4570Man · Mar 8, 2018

flingwing1969 said:
If you use a snatch block you will be pulling 90 degrees or so from the direct load pull, as well as doubling your pull. Throw a heavy blanket over the cable on the tractor side and it will dampen the snap back in the event of a cable failure.

Wrong. You can hook the snatch block to your load and hook the other end of the cable to a tree in the direction of the wince to double your pull. You can hook the winch cable directly to the load and hook the snatch block to a tree to change the direction. A pulley doesn't magically double the line pull.

SpringHollow · Mar 8, 2018

I do not understand why your rope is so hard on the capstan. The portable winch uses aluminum and works fine. But then I also use their low stretch rope which works great too. Maybe your ropes are tougher on the aluminum than what they use. I use a small plastic barrel to store the rope - just stuff it in and there is no tangling.

Ken

flingwing1969 · Mar 8, 2018

4570Man said:
Wrong. You can hook the snatch block to your load and hook the other end of the cable to a tree in the direction of the wince to double your pull. You can hook the winch cable directly to the load and hook the snatch block to a tree to change the direction. A pulley doesn't magically double the line pull.

You are right. Actually two snatch blocks would do that job. But changing direction is important when felling a tree, which is what I often do, as you don't want your tractor pulling directly in line with where your tree will fall, unless your line is much longer than the tree is tall.

iointerrupt · Mar 12, 2018

One final addition, I forgot to post the CAD files I made for this:

View attachment 543702

These are all SolidWorks (2013) files. The model isn't exactly the same as the built thing, but it's pretty close. You can take measurements off the model to get some idea of the scale of things.

This model also includes an unfinished top-link extension idea I'm still kicking around (to hold a pulley up high, like Farmi winches have).

Stomper · Mar 12, 2018

First off, great project and superior fab skill. That thing is top notch. The only problem that I can see with it is that you have now added another project to my long list of things to build.
There has been a few comments about using rock climbing rope, this is not a good idea. I am by no means an expert on ropes but coming from a rope rescue background here is what I know about the ropes I am familiar with. As for rope used for life safety goes there are two kinds, static and dynamic. Dynamic rope is mainly used in the sport of rock climbing because of it's stretching abilities. it will stretch in the case of a fall reducing the effects of the fall on the climber and belayer. IMHO the less of the 途ubber band effect you have IF the rope does break, the better off you値l be. Static rope is mainly used in the rope rescue business because of its low stretch abilities because the likelyhood of a long fall is extremely limited because of other safety factors put in place . Arborists also use static rope for the same reasons. Static rope is what you would want to use with this winch. The Sterling HTP 1/2" (13mm) rope we use at work on the rope rescue team has a rated minimum breaking strength (MBS)of 9084 lbs. I have 200 feet of New England KMIII 11mm (7/16)rope that I use for my personal climbing line for recreation use with a MBS of 8007 lbs. I paid $200 CAD for the 200 feet. Another option would be to check out the Amsteel brand of ropes. It's the synthetis rope used in the place of steel cable for atv and automotive winches. It is crazy strong for its size and has very low stretch. It is slippery stuff so I'm not sure if it would provide enough friction to be used in this situation. You might want to call up some of the arborist supply company's (wes spur, tree stuff ) and talk to them about ropes and what you are planning to do. They will most likely recommend a 5/8" or 3/4" rope arborists use for rigging. I know nothing about those ropes so I will not comment on those. Hope this helps

SpringHollow · Mar 12, 2018

As mentioned before, portablewinch has some respectable prices on non-stretch rope that they sell for use with their capstan winches. I have pulled logs through dirt berms with it. The 12mm rope is rated for 0ver 7000 lbs minimum breaking strength. If you need more than that, you would have to go someplace else. Here's their description so at least you know what it is if you need a larger diameter:

Double braided polyester rope (DBP): It features double braid construction for durability and low-stretch properties for safety. Its low cost and abrasion resistance make it a good choice for use with our portable winches where it is subject to friction and heat.

Ken

iointerrupt · Jun 9, 2018

A little update:

Here is the new redesigned top link attachment, with swiveling upper guide loop:

You can run the rope through the upper guide and get a little bit of vertical lift, makes getting over rocks a bit easier. Or you can skip the upper guide and just do a straight pull. Not a huge difference between the two, but it's better than nothing. I made it bolt-on just incase excessive winching forces destroy it. It flexes a little in use, but seems like it will hold up.

Here was todays haul, a 50' red oak and a 40' ash:

Winched both of them as whole trees, and then cut them into 10' lengths as they reached the tractor. No rocks in this area so it was an easy pull.

As for the ever popular topic of rope, I looked up the stuff I'm using, and it has an amazing 22% elongation rating. I desperately need to commit to buying some synthetic rope (4% elongation). Even the nylon ropes with 12% elongation would be a big improvement

SpringHollow · Jun 9, 2018

Check out the rope at portablewinch.com. I have used a rope from there for years.

Ken

AnotherBueller · Jun 13, 2018

For rope, I first tried 3/8" synthetic winch rope. One trip through the winch, and that rope is now pancake flat. Next I tried 5/8" double braided nylon rope. That worked well until outer cover got a small tear on it, and then it quickly unraveled. Finally I settled on 5/8" three-strand-twisted rope. It is holding up the best, but nevertheless the winch is very hard on any rope you run through it. I expect to replace the rope fairly frequently. (5/8 x 1�� NYLON ANCHOR ROPE/ DOCK LINE W/ SS Thimble ***MUST READ DESCRIPTION** | eBay)

Anchor and Dock line is designed to be stretch (around 20+%). Use triple braid instead, it has the least stretch around 2% for marine rope if I remember right.
AnotherBueller ex ocean racer in my crazy youth

AnotherBueller · Jun 13, 2018

AnotherBueller said:
For rope, I first tried 3/8" synthetic winch rope. One trip through the winch, and that rope is now pancake flat. Next I tried 5/8" double braided nylon rope. That worked well until outer cover got a small tear on it, and then it quickly unraveled. Finally I settled on 5/8" three-strand-twisted rope. It is holding up the best, but nevertheless the winch is very hard on any rope you run through it. I expect to replace the rope fairly frequently. (5/8 x 1�� NYLON ANCHOR ROPE/ DOCK LINE W/ SS Thimble ***MUST READ DESCRIPTION** | eBay)

Anchor and Dock line is designed to be stretch (around 20+%). Use triple braid instead, it has the least stretch around 2% for marine rope if I remember right.
AnotherBueller ex ocean racer in my crazy youth

Use the bigger drum, the line speed won't be that much greater and you'll get less slippage. Slippage = heat and nylon melts.
Look online for pulley size per rope diameter, I think i remember a 8:1(?) ratio. 1/2" rope = 4" pulley

SpringHollow · Jun 13, 2018

My rope is many years old and has held up well even with use in mud. But I probably only use it no more than 10 days per year. It is low stretch rope from portablewinch.com After a couple of years, I installed the larger drum for faster speed.

Ken

rustyshakelford · Jun 13, 2018

AnotherBueller said:
For rope, I first tried 3/8" synthetic winch rope. One trip through the winch, and that rope is now pancake flat. Next I tried 5/8" double braided nylon rope. That worked well until outer cover got a small tear on it, and then it quickly unraveled. Finally I settled on 5/8" three-strand-twisted rope. It is holding up the best, but nevertheless the winch is very hard on any rope you run through it. I expect to replace the rope fairly frequently. (5/8 x 1�� NYLON ANCHOR ROPE/ DOCK LINE W/ SS Thimble ***MUST READ DESCRIPTION** | eBay)

Anchor and Dock line is designed to be stretch (around 20+%). Use triple braid instead, it has the least stretch around 2% for marine rope if I remember right.
AnotherBueller ex ocean racer in my crazy youth

Check with your local FD if they have a high angle/confined space rescue team. Their rope has a life span and when it’s done it is typically used as utility rope. Might be able to snag some from them if they have extra

Brett