# Going Thru Cutting Edge Bolts Like Crazy



## Mark13 (Dec 3, 2006)

On my Western Unimount I have been going thru cutting edge bolts like they are going out of style. In the past 2 winters I'd break maybe 1 per winter. I've gone thru about a dozen of them so far this year and currently have 5 out of the 8 broke after plowing for 3hrs this morning. I'm using normal carriage bolts (same type of bolts from the first 2 years) and tightening them down with a dewalt 18v impact (about 300ft/lb). Any ideas?


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## grandview (Oct 9, 2005)

Grade 5 or 8's?


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## 2COR517 (Oct 23, 2008)

Mark - the bolts are not strong enough, and you are not getting the nuts tight enough. While DeWalt may advertise 300 ft/lbs, there's no way that thing is getting them tight enough. 

Go to your local Western/Fisher dealer and get a set of the grade 5 bolts they supply. If you don't have a good air impact wrench, get a long breaker bar and crank them down.

GV - sounds like he's getting grade 2 at Home Depot or whereever


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## augerandblade (Jan 17, 2009)

Is a China made bolt.??????????????????????//


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## Mark13 (Dec 3, 2006)

I believe they are 5's. I've had no problems with them the first 2 years I had my plow, not this season I go thru 2-3 per storm. Or in my case today, 5 so far. 


I'm going to try and find some grade 8 carriage bolts.


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## LoneCowboy (Jan 2, 2007)

They are plow bolts
go to a tractor implement dealer (like a John Deere dealer), they'll have them (and they'll be cheap)
and usually theirs are not chinese made. (hopefully) (I use grade 5 made in china bolts as rotary cutter shear bolts, they snap like nothing, way before the regular shear bolts do).


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## sno commander (Oct 16, 2007)

that impact may have a break away torque of 300 ft lbs but no way it will tighten them to that most are around 100-150 ft lb (tighten) like 2 cor said use a breaker bar. i think most plow carraige bolts are grade 5. are you using nylon lock nuts? maybe there vibrating loose and snapping.


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## grandview (Oct 9, 2005)

I'm wonder if he is not tighten enough and are working free ,then when he drops the plow it's starts to cut into them. Any pictures of these bolts?


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## 2COR517 (Oct 23, 2008)

grandview;927039 said:


> I'm wonder if he is not tighten enough and are working free ,then when he drops the plow it's starts to cut into them. Any pictures of these bolts?


I think that's what happening. No need for Grade 8. Grade 5 is probably better anyway. they have a little more give than the Grade 8.


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## bo alps hunter (Dec 20, 2009)

LoneCowboy;926677 said:


> They are plow bolts
> go to a tractor implement dealer (like a John Deere dealer), they'll have them (and they'll be cheap)
> and usually theirs are not chinese made. (hopefully) (I use grade 5 made in china bolts as rotary cutter shear bolts, they snap like nothing, way before the regular shear bolts do).


Correct, may be square like a carriage bolts, but plow bolts are stronger, and the head will be flush with the cutting edge. Carriage bolts are for woodworking!


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## D&S snowplowing (Dec 8, 2009)

the bolts are not strong enough switch over to a standard grade 8 bolt and nylon locking nuts with washers on both sides u should be fine


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## JD Dave (Mar 20, 2007)

Grade 5 is plenty. If they are the same bolts you've always used they should work now. Take the cutting edge back off and clean where the edge goes and reinstall with all new bolts and lock nuts. Use your Dewalt then get a breaker bar and a small peice of pipe to tighten them. We like to use a mini sledge and hit the head of the bolt at the same time when we are tightening the bolts on our blades. Also bring the bar with you and stop and check them after 30 min.


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## 2COR517 (Oct 23, 2008)

Dave's advice is right on. Wouldn't hurt to run a wire brush where the cutting edge sits, and along the back of the edge. That idea with the small sledge is great too.

Dave - do you put Fluid Film behind the edge?


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## JD Dave (Mar 20, 2007)

2COR517;928030 said:


> Dave's advice is right on. Wouldn't hurt to run a wire brush where the cutting edge sits, and along the back of the edge. That idea with the small sledge is great too.
> 
> Dave - do you put Fluid Film behind the edge?


No but we do use the wire brush which I forgot to mention. Thanks. Sometimes on our larger blade we actually will put a tack of weld on the end of the cutting edge because if you catch a curb while back dragging it will break the end bolt off. Not sure if your doing that also Mark.


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## dheavychevy38 (Nov 19, 2008)

I had that problem last year with mine. I think I wasn't getting the bolts tight enough and also noticed that my old edge was bent.:laughing: What I do now is tighten them and put a little tack weld on the threads of the bolt after I tighten them. No problems yet. If ya need a hand let me know always willing to help.


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## clark lawn (Oct 7, 2005)

you need plow bolts, they are not the same as carrage bolts. tighten them as tight as you can you will not break them.


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## cretebaby (Aug 23, 2008)

clark lawn;928230 said:


> you need plow bolts, they are not the same as carrage bolts. tighten them as tight as you can you will not break them.


What's the difference.


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## D&S snowplowing (Dec 8, 2009)

Hardened steel


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## cretebaby (Aug 23, 2008)

D&S snowplowing;928331 said:


> Hardened steel













You use plow bolts on these.


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## Mark13 (Dec 3, 2006)

I'm still using the cheap carriage bolts, got out the pneumatic impact and tightened them down. Plowed about 10hr on them since and they were still tight. 

I'm still thinking about taking a trip to the local plow dealer or local john deere dealer and getting stronger bolts. I'd rather not have my cutting edge fall off.:laughing:


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## t.i.b (Jan 17, 2009)

ive had nothing but trouble with grade 5's ive snapped atleast 24 this yr. i have 2 fisher dealers near me and the 1 sells grade 5 the other grade 9. i havnt had a problem with the grade 9's yet. i tack the nuts to the bolts also.


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## B&B (Nov 4, 2006)

JD Dave;928018 said:


> Grade 5 is plenty. If they are the same bolts you've always used they should work now. Take the cutting edge back off and clean where the edge goes and reinstall with all new bolts and lock nuts. Use your Dewalt then get a breaker bar and a small peice of pipe to tighten them. We like to use a mini sledge and hit the head of the bolt at the same time when we are tightening the bolts on our blades. Also bring the bar with you and stop and check them after 30 min.


Dave's info is spot on. If you're breaking 1/2" gr 5 bolts then your installation method isn't correct. Mating surfaces have to be clean and the bolts must have the proper torque. Most guys do not get them tight enough.


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## t.i.b (Jan 17, 2009)

ive tried everything with the grade 5's as they are more common but they break plowing roads(never had a problem doing drives with em) i'm 240lbs and use a breaker bar and hammer and cant believe im not gettin them tight enough. just my 2cents.


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## B&B (Nov 4, 2006)

t.i.b;928538 said:


> ive tried everything with the grade 5's as they are more common but they break plowing roads(never had a problem doing drives with em) i'm 240lbs and use a breaker bar and hammer and cant believe im not gettin them tight enough. just my 2cents.


You can over tighten them too. 

Torque wrench is the correct way to do it.


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## Deco (Nov 14, 2009)

Mark13;926644 said:


> On my Western Unimount I have been going thru cutting edge bolts like they are going out of style. In the past 2 winters I'd break maybe 1 per winter. I've gone thru about a dozen of them so far this year and currently have 5 out of the 8 broke after plowing for 3hrs this morning. I'm using normal carriage bolts (same type of bolts from the first 2 years) and tightening them down with a dewalt 18v impact (about 300ft/lb). Any ideas?


you need NYLOCK NUTS (nuts with plastic so they dont back out )wesport


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## cretebaby (Aug 23, 2008)

t.i.b;928474 said:


> ive had nothing but trouble with grade 5's ive snapped atleast 24 this yr. i have 2 fisher dealers near me and the 1 sells grade 5 the other grade 9. i havnt had a problem with the grade 9's yet. i tack the nuts to the bolts also.


I've never heard of grade 9's.


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## Deco (Nov 14, 2009)

no one has mentioned ,including him , what type NUTS he is using . 

NYLOCKS are the key ,


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## t.i.b (Jan 17, 2009)

nylocks come with the grade 5's the grade 9's are black and instead of having the lines on the head to indicate grade they have 2 circles like a bullseye. the grade 9's come with lock washers and nuts. it never crossed my mind about over tighting. b$b do you have the torque specs?


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## dheavychevy38 (Nov 19, 2008)

Steel type lock nuts are the proper ones.


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## Deco (Nov 14, 2009)

dheavychevy38;928732 said:


> Steel type lock nuts are the proper ones.


what'd you think i meant , plastic ? :laughing:


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## Mark13 (Dec 3, 2006)

Deco;928549 said:


> you need NYLOCK NUTS (nuts with plastic so they dont back out )wesport





Deco;928555 said:


> no one has mentioned ,including him , what type NUTS he is using .
> 
> NYLOCKS are the key ,


So I can't use lock washers and a standard nut?


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## B&B (Nov 4, 2006)

Lose the lock washers and hex nuts Mark. Use a crimp nut instead. Technically called a "torque prevailing nut".


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## 2COR517 (Oct 23, 2008)

The best ones are the nuts that have a dimple on three of the flats. They work *mulch* better than the nylocks. But lockwashers really should work if you get them tightened properly.


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## Mark13 (Dec 3, 2006)

B&B;928763 said:


> Lose the lock washers and hex nuts Mark. Use a crimp nut instead. Technically called a "torque prevailing nut".


I'll have to look for some of those, don't think I have ever heard of them before.


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## B&B (Nov 4, 2006)

I'll bet you have seen them before you just didn't realize it. Any good fastener shop will have them. Here's what you're looking for..


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## Deco (Nov 14, 2009)

BB , nylocks ??


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## 2COR517 (Oct 23, 2008)

Mark, the nuts B&B is refering to will probably feel like they are the wrong thread. They are quite tight. They work great.


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## B&B (Nov 4, 2006)

Deco;928794 said:


> BB , nylocks ??


Nope, torque prevailing nuts. Two different things. Nylocks are soft.


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## Deco (Nov 14, 2009)

B&B;928811 said:


> Nope, torque prevailing nuts. Two different things. Nylocks are soft.


rodger that ....


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## dheavychevy38 (Nov 19, 2008)

Thats what I meant when I said steel thank you b&b Mark go to botts they have them and they aren't that bad on the price. Go to the old building talk to gordy and tell him what you are doing he'll get you the right stuff.


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## Mark13 (Dec 3, 2006)

dheavychevy38;928830 said:


> Thats what I meant when I said steel thank you b&b Mark go to botts they have them and they aren't that bad on the price. Go to the old building talk to gordy and tell him what you are doing he'll get you the right stuff.


Ya, I'll stop in there tomarrow. I was just there thursday and talked to Pat, had to get some plow pins and stuff. Should have gotten bolts then.

Arn't those torque prevailing nuts like lugnuts B&B? They look quite similar to the ones on atvs.


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## B&B (Nov 4, 2006)

Mark13;928845 said:


> Arn't those torque prevailing nuts like lugnuts B&B? They look quite similar to the ones on atvs.


They do look similar but the taper is on the opposite end and not designed to seat into the object you're tightening it against (unlike the wheel on an ATV for example). The tapered side is where the nut is crimped closed in order to create an interference fit with the bolt to hold the torque.


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## Mark13 (Dec 3, 2006)

B&B;928893 said:


> They do look similar but the taper is on the opposite end and not designed to seat into the object you're tightening it against (unlike the wheel on an ATV for example). The tapered side is where the nut is crimped closed in order to create an interference fit with the bolt to hold the torque.


Ok, I'll see what I can find tomarrow. Probably will try Fastenal.


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## B&B (Nov 4, 2006)

Fastenal will have exactly what you need.  They refer to them as "top lock nuts" and a box of 25 will be around $12.


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## plowking15 (Jan 16, 2010)

We've gotten some of our plow bolts,shoe bolts at fastenal. When we install bolts on our cutting edges on trucks,grader, we have one person tightening with an air gun whlie another person is hitting the head of the bolt with a small sledge hammer. plowking


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