Aligning Guards on a Sickle Bar

[hope farmer]

In the process of rebuilding a 7" bar on a McCormick A-21 mower and have a question about the alignment of the guards. I"m replacing all the guards (and ledgers, and hold downs) with OEM parts. Some of the guards have nubs left on them from casting, which makes it difficult to get them all aligned parallel with each other. I"ll probably take a grinder and knock the nubs down so everything fits. I"m just wondering how important is it for the guards to all be parallel. Appreciate your time.

 

[LarryT]

I find it very important for indexing the knife and setting the clearance of the knife to the ledger plates. I am in agreement with you gently grinding off the casting flaw. Sounds like you know what your doing. Good luck and happy Thanksgiving

 

[JRSutton]

I'd say if it's a casting flaw, and you're sure you're installing them correctly, then definitely do what it takes to make them sit right. People making guards these days don't care how they fit, as long as the part looks about right. You have to worry about that yourself.

And a sickle mower is one of those things that only works well when everything is fine tuned and aligned properly.

In the grand scheme of things, misaligned guards probably wouldn't make much of a difference as long as the ledger plates are on the same cutting plane, but you'll appreciate your efforts if your trying to diagnose some other problem later on. You'll be glad to KNOW all the guards are installed properly.

To me, that's reason enough to do it right.

I'll be restoring an A21 myself over the winter. I'd love to see pictures of yours or hear more about it.

 

[GordoSD]

There is a tool, or you can make one. Has "cup" on one end of about 5 foor long 1/12 inch pipe. Slip it over the guard and stand on it or jack it up to bend the guard just a little to get perfect alighnment.

 

[keh]

X 2 on what LarryT said. Back in the day when sickle bar mowers were used professionally it was sometimes cost effective to buy a complete new bar assembly when the old one got worn.

KEH

 

[hope farmer]

This is a old (new to me) mower. I bought it last year and plan to use it on a IH140. It came with a shorty five foot bar and I'm replacing it with a seven footer from a A24. I was a little concerned about putting the bigger bar on it because the running gear of the A21 looks somewhat lighter than the A24. The manual for the A21 does show an option for a seven foot bar, so we'll see.

The mower aligns and bolts up good on the 140 except for the PTO slip tube. I noticed the outer tube is bottomed out against the univeral head. Seems to fit ok, and roll ok, I just don't like the idea of not having any room. Probably trim a little off the tube.

 

[TomH in PA]

Also make sure the bar is clean before you bold the guard on. Little bits of rust of other crud will make them sit wrong. After that, a 2 pound hammer works for me.