Shear Frustration. (1 Viewer)

[Northern HJ61]

Just joined... largely to address this issue.

My daily driver is a 1989 HJ61. Spend a few weeks of the year in the bush here in Northern Alberta. Love my yoda except...

I've been frustrated over the seemingly weak load capacity for my P.T.O winch. Not due truly to the winch itself but as a result of shear pins doing their job. They seem to let go at a very low load capacity.

I've heard of people using nails and bolts instead and increasing their pulling power. The fear then, of course, is ratching out the guts or twisting the yoke off the shaft.

Does anyone have an honest, non bush myth, way of compensating safely for the soft shear pins? If you drill out the pin path a bit and put in a hardened dowel pin (like the one I've already bought in consideration at a bolt supply house) am I weakening the pin housing and placing the PTO at risk?

Knowledgable advice required...

 

[Lost]

do you use a snatch block?

 

[Tvaldriz]

2x on the snatch block. Doubles your pull power.

 

[hank14]

2x on the snatch block. Doubles your pull power.

But if he's having the shear pins break before getting the job done, increased pull power is not going to help. Stronger shear pins may cause something else to malfunction.

 

[lovetoski]

But if he's having the shear pins break before getting the job done, increased pull power is not going to help. Stronger shear pins may cause something else to malfunction.

Nope. Lets assume his shear pin is breaking at 4000 lb load. Adding a snatch block (ignoring friction losses) means he can pull up to a 8000 lb load w/out shearing the pin. Line speed drops in half, force applied doubles. Similar princaple as with the transfer case and low range.

 

[hank14]

Ahhh, you're right. Basic physics. I concede.

Spend $75.00 on a good snatch block and you should be good to go!

 

[RockDoc]

Relevant thread:

https://forum.ih8mud.com/diesel-tech-24-volts-systems/27371-pto-winch-rating.html

 

[Northern HJ61]

I've since been advised to try using a roll pin instead of a shear pin in order to increase it's strength. Apparently one the same diameter as the foctory shear pin offers quite a bit more strength. Plus, there's no need to expand the pin housing. Reportedly you just use a nail set and flare the ends of the roll pin to keep it in place. Worth a try I guess...

 

[Root Moose]

A roll pin is not a shear pin. Might as well put a hardened bolt at that point.

 

[Northern HJ61]

Perhaps, but there isn't a bolt as small as the diameter of the pin housing...

I'm just exploring my options here. I don't want to resort to drilling out he pin path as it will potentially weaken the shafts yoke etc.

 

[nodaksn3]

Recommendation: Do NOT replace the shear pin with anything except another shear pin. It's there for a good reason. Be safe and go the snatch block route. Ned

 

[The Dude]

I drilled out the sheer pin for a 1/4 roll pin (I think that's what I did) To date no failures but if it is anything but a simple pull, out comes the snatch block.

The failure, I am told, will happen inside the winch head. There is a big ??brass?? gear that will strip.

I figure go till she blows and then replace with a PTO driven hydro pump for a hydro winch.

 

[Tim-HJ61]

I had the same problem and have replaced the shear pin with a roll pin. To date no breakages, but easy breakages doesn't help give confidence to the winch that it will really pull me out of a bad situation.

One suggestion I heard was to make sure I only ever ran the winch in 1st gear at idle speed - unless under no load.

Combined, the roll pin and low revs, have led to no breakages as yet.

BTW, I found the following specs for the winch at:
http://www32.ocn.ne.jp/~takachi/Introduce/Hj61v/hj61v-spec.htm
You'll need to get Google to translate it.


P-HJ61V-MEMZX : SPEC "WINCH"
Leading power source Engine
PTO structure Choose sliding formula
PTO gear ratio 1 . 000
PTO gear oil capacity ー 0. 5
Maximum power driver 1,800 kg 1 (pin rupture share).
Dimensions wire 8 mm×45 ｍ
(JIS) Material Standards (JIS) wire ＳＷＲＨ－６２Ａ 62A-SWRH
Winch drum size 80 mm × 198 mm × 184 mm
Winch gear ratio 1 : 33
Gearbox oil 0 . 3 Litre
Share pin Dimensions 4 . 3 mm×50 mm 4. Mm × 3 mm 50
Pin share materials SC steel

It shows the rating of the winch is 1800kgs, which is less than the tare weight of the vehicle and no wonder we break pins! I had been told by a winch specialist they were an 8000 pound (3500kgs) capacity.



Tim

 

[hoppie]

Were can I pick up a roll pin? What exactly is it?? I haven't blown a sheer pin yet, but I'd rather find something that I can source locally without having to order. Thx

 

[Northern HJ61]

Pretty sure you can pick one up at any bolt/industrial supply store. Is it blasphemy to just wish I just had an electric winch? This all seems like voodoo mechanics...