Rear Blade King Pin replace

[JakesDad1]

New to the forum, hope you guys can help.

25 years ago we moved to Connecticut. The driveway is 700 feet long, unpaved, up a 13% grade. My first purchase was a Ford 8N and a 6' heavy duty grader blade for summer and winter driveway maintenance. The tractor died and was replaced by a Nortrac 20HP, 4x4 tractor (chains and weights all way around).

Now the grader has died! At the end of the current snow storm the king pin broke. I've already tried to weld it once (flux core wire feed). It held for 1 storm.

The king pin is welded in.

The question is: can I just cut the welds and replace with another bolt, or am I missing something.

To replace this blade in todays market it looks like about $1K, too much for me. The other alternative is to get a cheap one. Any Ideas?

 

[nuffer460]

First, welcome to TBN. You'll like it here! Second, can you post a couple of pictures. May help understand both the welds and/ or bolts. That being said, was it welded to replace the bolts? If your welder does not burn hot enough. maybe you have a local welder that can come out and grind out the old weld and really burn in a new weld. I have a NorTrac 254 w/ FEL. They are stronger than they look.

 

[JakesDad1]

Thanks for the response. Being new to the forum don't know if I can post pictures. I'll go home at lunch and see what I can do.

The original pin is about 1 1/2" in diameter and welded into the frame top and bottom. When it sheared, I attempted to weld at the brake. I ground the sides of the bolt so I could build a weld from the middle and worked my way out. I am a lousy welder. As you suggest, my welder (or The Welder) was not up to the job.

 

[rankrank1]

I would think your blade should definitely be repairable. Pics would definitely help until then I can offer a few suggestions based around only having your little mig to work with. As you already know light duty 115V migs like you have are not good for heavy fabrication (I have one too but do like it - it just has limitations):

a) Assuming nothing is broken but only worn oblongish: I have had great luck using my little mig it to build up pins and holes in heavy iron holes that are worn oblonged and wallowed out. Build up the wallowed out hole with weld and then use a handheld die grinder with burr tool (either electric or air) to make it close to round again. You can also build up the pin in worn areas and then use your 4.5" handheld grinder to make it close to round again. If you do a repair like this then it should be possible to return everything back close to its original design and tolerances to work again.
b) Now if something is indeed broken: It sometimes possible to redesign a suitable repair adding metal stock where needed such that your little mig welds do not have to take the brunt of the forces applied - a design such that the little mig welds only have to hold things in place.
c) If it is not possible to redesign and something is broken: In depseration, I have had good luck repeatably layeringing and criss-crossing mig welds and of course cleaning slag between layers. Warning this method does lead to some terribly unsightly welds, but what is important trying to build strength with an admittingly undersized welder but if its all you got....you sometimes find a way.
d) If a bolt/pin is only sheared as indicated in your last post, you should be able to cut that out and then use a replacement bolt with double nuts to do the repair - double nutting would allow the bolt to stay a little loose for pivoting and allow easy repair in the future if needed. Finding an 1 1/2" bolt may not be real easy/cheap but it is possible. You could simply make a new pin from a piece of solid bar round stock which should be rather cheap and readily available from a local scrap yard/metal supplier. If you do not trust your little welder to hold the retainer pins on the new 1 1/2 pin then maybe cross drill them and use a 3/8 or 7/16" bolt for the retainers kinda like cotter pins.

(NOTE: I only utilize some of the desperation type approaches on items that are not structurally critical. In other words, if it breaks then neither me, anyone else, or my equipment would be adversely hurt or damaged in any way).

 

[Soundguy]

if it was built.. it should be repairable.. though maybee not with a 110v flux welder. A beefy crackerbox, torch and angle grinder may bring more joy...

soundguy

 

[JakesDad1]

Thanks for your input! I've been unable to log back in, now I guess I'm set. This is the situation:

Now I have ground off the welds as best I can. The pin came out of the blade half. I'm stll working on dremeling out the welds on the tractor side. I can see daylight through most of the welds, I just had to go to Home Depot for more dremel cut off wheels. When I can knock out the old broken pin I'll have a nasty looking hole.

My daughter's father in law has a stick welder and has offered to help. I've ordered a 1.5" bolt, nut and washers. I'll post my results.

 

[JakesDad1]

There has been progress. Last night I finished cutting the old king pin out.

and I'm left with some pretty big holes.

and at lunch time the UPS driver left a package for me at the end of my driveway. :cloud9:

I've got $75 tied up in bolts, nuts, and washers. Hopefully my buddy will be able to help me put this back together. :drink:

 

[Soundguy]

don't look too bad.. nothing a smoke wrench and welder can't fix!



soundguy

 

[mjncad]

Were you literally using a Dremel to cut those welds? If so, get a 4-1/2" angle grinder for future chores like that.

I have a Dremel, and it's a great tool; but not for that kind of work.

 

[Soundguy]

omg.. I missed that. for sure I would have used a 4.5" angle grinder or at least a die grinder with 2" wheels... doing ti with dremel wheels must have been time consuming!

soundguy

 

[JakesDad1]

Were you literally using a Dremel to cut those welds? If so, get a 4-1/2" angle grinder for future chores like that.

I have a Dremel, and it's a great tool; but not for that kind of work.

I thought so too, so I started with a 4 1/2" grinder. The problem was that I couldn't get into the weld with that big a cut-off wheel. I switched to a 1-1/2" dremel cut-off wheel and was able to get into the weld without cutting the end of the implement off. :mur:

 

[Soundguy]

sounds like smoke wrench time!

soundguy

 

[JakesDad1]

Fixed at last, just in time for the next snow storm!

Thanks for all of your suggestions!

 

[rankrank1]

Glad you got it together - it should be good for many years to come. Thanks for posting follow-up pics. We like to hear (and especially see in pics) how a poster made out on their repair project.

I do have one question: I can see where the nut (and cross drill for cotter pin) is, but I can not see where the bolt head is. Would it have been possible to sorta re-design this kingpin system such that a longer bolt could have been used and then maybe double nut it on the bottom - double nutting would allow you to adjust for wear if ever needed? Also, if the bolt ever breaks again, then cutting it all apart and rewelding would not be necessary. Simply use a drift punch to knock the broken bolt out and and install another long bolt.

 

[JakesDad1]

I had originally considered your suggestion rankrank1, but we were constrained by the material we had available. I measured the original bolt (3 times) and came up with a lenght of 7". I don't have a local source for 1-1/2" bolts and so had to order (internet). I did not consider that the new nuts would be 1-1/4" deep. You will notice that there is a 1" gap between the lifting member and the fixed rotating plate. The king pin failure occured in that space. We needed to beaf-up the connection of the lifting member and that plate but keep the 1" gap. So we trimmed the head of the bolt so it would be nearly flush with the top of the lifting member. That gave us extra bolt length. Then we welded the piss out of it, and added some extra stiffeners to the site. It will never be replaced again. If it breakes now, its time for a new grader.

 

[Soundguy]

good luck with it!

soundguy

 

[rankrank1]

...but we were constrained by the material we had available...So we trimmed the head of the bolt so it would be nearly flush with the top of the lifting member. That gave us extra bolt length. Then we welded the piss out of it, and added some extra stiffeners to the site. It will never be replaced again. If it breakes now, its time for a new grader.

Thanks for the answer as I was simply curious. Sounds like you took the material you had available and made it work - certainly nothing wrong with that.

Having access to a capable welder is such a great thing almost anything can be repaired/rebuilt with a welder. Matter of fact I am confident you could repair/rebuild this blade again in 40 years or so if it needs it again.

I spent way too many years without a welder. Trying to fix some things without a welder is nearly impossible. Now that I have a 115V Lincoln MIG and and AC-225 Lincoln buzzbox arc welder for the bigger stuff, I can usually cobble almost anything back together even though my welding skills are lacking.

I would recommend that you start scanning Craigslist for a deal on a Lincoln AC-225 tombstone buzzbox for somewhere around $75 or so as they can be found all the time for $75 to $100 and last forever.The older ones with copper windings are a little better than the newer ones with aluminum windings, but either will actually work okay. A Lincoln AC 225/DC 125 would be even better, but will cost more $150-$200 used but you do gain DC welding ability but with limited DC amps. Hobart Stickmates or Miller Thunderbolts are okay too, but the Lincolns are a little more durable in my opinion as you just can not kill them. Having a $75 Lincoln around would be cheap insurance for the next time that you need to weld some thick iron like this.

 

[JakesDad1]

I had a blast trying to figure out how to stick weld. My buddy was pretty good with it. I would love to try my hand, but have no real need. This is the first heavy steel repair/build I've had to do in about 20 years. I'm currently working on a motorcycle modification and my wire feed is doing the job. Thanks for your recommendations though.