Proper way to connect linkages

[krystolo 504]

When using a clevis pin to connect the attachment to the rock shaft, how snug should it be?  Should I add washers to make a tight fit, or is it ok to have some play in the connection?

[Jeff-C175 7,199]

There should be some clearance, but not 'slop'.  Snug or tight is not good, it increases wear and the pin can wear through and break.

Edited April 15, 2021 by Jeff-C175

[Mickwhitt 4,593]

I replaced the pins in mine with bolts so that I could have more control over the amount of tightness. It works well and the whole mechanism feels more positive in action. There's no excess movement of the hand lever when I raise and lower the plow frame.

Im going to make the solid link for my plow and do away with the chain link and lift arm so I can apply down pressure and so removing any slop is more of an advantage.

Mick

 

[Stormin 9,981]

16 minutes ago, Mickwhitt said:

I replaced the pins in mine with bolts 

 

I've done the same. Bolt, 2 washers and 2 nuts as lock nuts.

[ranger 1,746]

When replacing pins with bolts in any linkage, especially ones which carries any significant loading, or are constantly moving, you should try to use “Bolts” not “set” screws. Bolts have an unthreaded section under the head, set screws are threaded the whole length. If you use a set screw in a heavily loaded / stressed linkage, the threads will wear quickly, as will the Clevis!! Like rubbing your finger along the cutting edge of a knife blade, as opposed to rubbing it along the side! In these situations, I tend to use socket headed cap screws, ie, “Allen Screws”, as these are a harder / stronger grade of steel. 

Doug.

[ebinmaine 67,311]

I've some the same as above. 

Another word... Get grade 8 bolts. On all our new builds or rebuilds we now use grade 8 everywhere with nylon locking nuts. 

Mail order price is the same as grade 5. 

I keep a decent assortment of them in stock. 

[ranger 1,746]

4 hours ago, ebinmaine said:

I've some the same as above. 

Another word... Get grade 8 bolts. On all our new builds or rebuilds we now use grade 8 everywhere with nylon locking nuts. 

Mail order price is the same as grade 5. 

I keep a decent assortment of them in stock. 

Good advice. Talking about different grades of bolt just reminded me of a training course I attended in Germany. At the  “Mulag” factory in the Black Forest. Two sections of an MB Unimog mounted flail mower boom arm, (huge hedge cutter), were bolted together with bolts nearly twice as long as you would think they should be. Asking why? We were told that the correct length bolts in 8.8, (metric) grade weren’t strong enough, there were like eight bolts  holding two sections of the boom together! Imagine two poles, each with a flange on an end, with the flanges bolted together. Using the next grade up didn’t work either. 12.9 grade “Allen” bolts were strong enough, but they were too brittle to withstand the shock loadings encountered. The solution, use longer bolts with spacers, the extra length of material allowed more “stretch” and absorption of shock loadings in tension with out failing, the “correct” length  bolts couldn’t. It looked a bit strange, but worked!  

A good excuse to give, if asked, for that,” get you home”,too long, with a dozen washers, temporary bolt you fitted to replace one that was lost, and hadn’t gotten around to sorting yet.

Doug.

Edited April 15, 2021 by ranger

[squonk 41,039]

My Power King is assembled with grade 5 fine thread bolts. Nothing falls off or breaks 

[ebinmaine 67,311]

4 minutes ago, squonk said:

fine thread bolts.

I like that

[ebinmaine 67,311]

4 minutes ago, squonk said:

My Power King is assembled with grade 5 fine thread bolts. Nothing falls off or breaks 

Grade 5 is perfectly fine. I only got grade 8 because it was the same price....

[krystolo 504]

@ranger haha!  I can see myself giving a 30 minute dissertation on why I am using extra long bolts to hold my equipment together. My barn mates would fall asleep!

 

Super interesting explanation, though. 

[krystolo 504]

Overall, I like using the clevis because I don’t need tools to change the attachments, but will definitely consider bolts if I land on a favorite that’s going to live on the tractor more permanently. 
 

@Mickwhitt I have a solid linkage. It’s nice to have the downward pressure, especially on the grading blades. 

[Handy Don 12,163]

3 hours ago, ranger said:

The solution, use longer bolts with spacers, the extra length of material allowed more “stretch” and absorption of shock loadings in tension with out failing, the “correct” length  bolts couldn’t. It looked a bit strange, but worked!  

 

Had a question on my materials final in engineering school set up like this. Correct answer was a bolt more than twice as long as expected with big spacers under the head and the nut to take up the extra length. (Thankfully, my engineer Dad had shown me this trick in the shop on some big machines so I had an idea of how to solve it.)

Yes, a bit odd to be fascinated by this stuff!

[8ntruck 6,991]

You might want to consider using shoulder bolts in the clevis instead of pins. Shoulder bolts have a long smooth shank with a smaller, shorter threaded section at the end.  

 

Bolted joint design is an interesting subject.  We had some dies that were frequently breaking bolts - not a good thing 'cause the broken bolt pieces would make scrap product and worse, die pieces would occasionally fall out and get turned into D2 dust in the 4000 ton press. The repair bill for such a failure was in the $8,000 to $10,000 range.

 

We went to longer fine threaded bolts and changed the design of the die details to solve the issue.  While waiting for the updated die details, we had the die techs check the torque on the suspect bolts at break times and lunch breaks.  We also discovered that the brand of the bolts made a difference.  Had to defend our preference for the higher cost bolts to the purchasing department.

[roadapples 6,983]

On something like a down pressure rod I  would use a softer bolt. I'd sooner replace the bolt than wear the hole bigger. Just my reasoning...

[Lee1977 6,648]

On my grader blade I had the pins welded in. One on the solid link the other on the grader blade. That worked until I raised the tractor,

Then I had to build an adapter kit as the blade would not reach the ground. It now has a loose pin between the adapter and the solid link.

[krystolo 504]

15 hours ago, Lee1977 said:

On my grader blade I had the pins welded in. One on the solid link the other on the grader blade. That worked until I raised the tractor,

Then I had to build an adapter kit as the blade would not reach the ground. It now has a loose pin between the adapter and the solid link.

smart idea!