Mower cutter bar bolt issue

[hardpan99]

My cutter bar uses 7/16″ coarse thread plow bolts to hold the guards and knife clips. The problem I have is that on the holes where there are NO clips, the countersink on the top of the bar is so wide that the sides of the nut dig into the countersink (see photo). So I have been running this bar with the bolts going from the top to the bottom (with the nut on the bottom of the bar holding the guards on.) Does anyone else have this issue? I think lug nuts with 1/2″-13 bolts would work and allow the flat head of the bolt to be on the bottom of the bar as it should. The problem is that I can’t find a source of tapered nuts (lug nuts) in a 1/2″-13 thread or a plow bolt in a UNF thread. All lug nuts that I can find use UNF threads. I also thought that some sort of washer to fit in the countersink on the top of the bar would also solve the problem. Does anyone else have this issue? The mower does run with the nuts on the bottom but as you could imagine, they catch on clumps of hay, rocks etc…

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[Mark Cowdrey]

Not an answer but a comment that MIGHT be useful:
I use haybine guards on my #9 High Gear Mower w a 5′ bar. The nuts are on the bottom and don’t seem to be an issue for me. Could be one of those things that seems like it should be an issue but actually isn’t. Just saying.
How is your lift tension? Bar just skating along the ground?
Good Luck,
Mark

[hardpan99]

I guess you’re probably right. Its a non-problem type of problem.

[Jay]

Norm Macknair (BW Mackair, Lewistown Pa) has beveled or cone shaped nuts of the size you are looking for. Those bars all came with the nuts on the bottom so the nuts and threads wear off eventually. Most times people turn the bolts over now, the guards have the inset for the square, flathead bolt, the cone nuts help in my experience. Jay

[Donn Hewes]

Master Equipment, or almost any Amish Mower shop or parts supply will have the 7/16 cone nuts. They are what everyone is using. That will keep all the nuts on top. Years ago the Hold downs where beveled to except the bolt and then all the bolts would be top to bottom. I think this was a pain when they came loose or fell out, but it did leave a cleaner bar top where cutting passes over.

[hardpan99]

That’s interesting. I just assumed the originals always had the nuts on top.

[Donn Hewes]

I think this maybe obvious as we sort of explained, but as you look at the Amish (or Bailey) rebuilt mower you will see half the cone nuts right side up (on top of the hold downs) and half are up side down (on the cutter bar). Just a tip for putting it all together.

[Mike Rock]

As an aside, who carries grain binder rock guards, and most importantly, grain binder sickle sections?

[Jay]

Again, I would check with Norm Macknair for parts of that sort. Jay

[wally b]

You can buy those taper topped nuts at any good fastener supply shop. The cutter bar is designed to have the carnage bolt head on the underside of the cutter bar.

wally

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