international a-21 sickle mower refurbishing - help needed

[kubotagary]

i have a kubota l3800 hst
i grew up in the city, this is the first tractor i have owned, luckily i have a neighbor who taught me the ropes
i recently picked up an old sickle bar mower
from my internet research its an a-21 international sickle bar mower
we are adapting it to fit my 3 point hitch, after 2 days of drilling, welding, and fabbing up some parts, we have it mounted
turned on the pto, everything works, but there is a loud clacking noise that is intermittent, sometimes few in a row, sometimes a few seconds in between noises
i marked the 2 pieces of the clutch (in by the large top flywheel) and ran it, then stopped and found the marks were off
so i determined maybe my clutch is slipping, i tightened the spring on it a few turns, still no change or improvement
also of importance, the knives arent binding and the 2 gear boxes were both bone dry when i found it, but we filled them up prior to use
any help would be greatly appreciated!!

 

[Creamer]

Something in the sickle is sticking. Can you pull the sickle in and out by hand? If not it is too tight. I would also look at the back of the sections to see if the corner of one may be catching on a wearplate or holddown - sometimes sliding by soimetimes hitting and causing your clutch to slip.

If it will cut the grass without slowing strokes I would not tighten the slip clutch anymore - that is not the root cause.

If you find the sickle hard to move but cannot define a specific problem you may need to loosen it all up and reset them one-by-one.

 

[kubotagary]

ok i will try adjusting that
when the sickle is hooked up to the tractor and not connected via PTO, i can rotate the flywheel, but it requires quite an amount of effort. when we had it running, we checked the knives by placing our hand against them after to check for heat/friction and didnt find any hot spots
i did find however, when initially removing & sharpening & re-installing the blade that it took quite a bit of wiggling to get it to slide in just right into the track
have not yet tried to cut grass

 

[Creamer]

It sounds more like an intermittent catching than a constant rub from the way you described it although the sickle should move fairly easily by hand, i.e. less than 5 lbs force to move it.

 

[flusher]

ok i will try adjusting that
when the sickle is hooked up to the tractor and not connected via PTO, i can rotate the flywheel, but it requires quite an amount of effort. when we had it running, we checked the knives by placing our hand against them after to check for heat/friction and didnt find any hot spots
i did find however, when initially removing & sharpening & re-installing the blade that it took quite a bit of wiggling to get it to slide in just right into the track
have not yet tried to cut grass

Sounds like there's a lot of excess friction in the sickle mechanism. Could be a bent bar. Could be that the sickle sections are too tight against the ledger plates in the guards. The hold down clamps on the bar also might be too tight. Check both ends of the bar to be sure they're not hanging up on something.

 

[kubotagary]

being a complete rookie
does anyone have a guide/link or could explain how to check the ledge plates etc
i found that 2-3 of the triangluar teeth are loose and is it possible that the tooth is wobbling and catching?
so on the one stroke it binds, the clutch disengages (the clacking sound) then on the return stroke the tooth no longer catches...
i am going to get my neighbor to assist me in tightening up some of the teeth/rivets s

 

[Creamer]

I am not sure how easy it is to pull the sickle out but I think it would be good for the following reasons:

1) You can sight down it to check it for straightness and straighten it if need be
2) It is easy to tighten the sections that are loose - just place the the rivet head (underside of sickle) on an anvil or piece of steel making sure the loose rivet is pushed up and the sickle section is flat to the bar and hit the top of the rivet to smash it down. Do not be gentle but be careful handling the sickle bar so you do not bend it. (I use the pad on my bench vise for the anvil.)
3) You can inspect the ledger plates and guards. The guards should be in alignment up and down and the ledger plates should be tight.

After these are good, loosen the guard bolts that have the holddowns and wear plates attached. Slide the wear plates as far back as possible. and then insert the sickle bar - it should go in easily. Now push the wearplates forward enough to be under the back edge of the sickle sections and up against the back of the sickle bar but not real tight. Making sure the wearplates are down push down on the front of the sickle section and make sure it is lying flat on the ledger plate in the guard. Do not tighten the bolts yet but go down the entire sickle and make sure these are all good. The wearplates should stay where you put them. After you have the whole sickle bar adjusted go through and tighten the bolts making sure things do not move (I would not have connected the head of the sickle to the drive yet.)
Now go through and push down on all the section under the wearplates to make sure they are properly held down. They should be supported in the back by the wearplates so that they lie flat on the guards and are not tipped (If they are tipped you will need to adjust using shims but this is rare.) and are pushed forward in the guards but not so that it is hitting the front of the guard. If the sickle moves up and down more than 0.020-0.030 tap down on the holddown in that area to hold the sickle in place. Otherwise you will get a sickle that gets grass caught between it and the guard as the tight scissor action is not there.

Once you have gone through this you should be able to connect the sickle head to the drive and all should be good. Remember the keys are a sickle that is held in place - level and straight - and that moves freely. Now start it up and make sure you do not have any hot spots as you mentioned you did before.

Good Luck!

 

[kubotagary]

little update here
tooth the knives out and really worked over some rivets, one or two of the teeth were quite loose and we cinched up the rivets
the knife bar slides in and out so much easier now
we have the center link rigged up with a chain but it doesnt prevent the mower from tipping forward or back under extreme angles, if i get the lower lift arms up too high
this afternoon we are going to try to fab up a triangle of sorts to mount to the center point link

 

[kubotagary]

the mower works
the loose teeth was definetly the problem
fabricated a more solid framework for the top link that prevented it from tipping forward and back on the previous chain mount...
here are some photos, and thanks to all who gave such accurate advice!!

 

[Creamer]

That looks like it makes a lot more sense. The fore/aft tilt is critical to cutting - too far forward and it is always digging in the junk, too far aft and it slides over and does not cut.