MF500 COncave Adjustment

tweedler · Sep 21, 2014

New to MF combines, just recieved a 550 - good overall condition, with 13ft grain head, wide concave spacing. Handbook says concave at front should be 8mm when adjusting lever is at notch setting 5, 1.5mm when at notch setting 1 and 32 mm when at notch setting 11 (full open). I tried to measure clearance between rasp bar and concave front bar through the little access window on RHS, clearance (at notch setting 5) was almost 3/4" - I adjusted the long concave rod full in and full out, when full in, the concave clearance lever wouldn't close any more than notch setting 3, when adjusting the rod full open, the concave clearance lever wouldn't exceed notch setting 8 - yet I can't see the drum hitting the concave anywhere - Im pulling my hair out, need to cut Rye (front setting 5mm read 3mm), from what I can see, I have no chance of getting those measurements - what am I missing here ? Thanks
Tweedler

RGMartin · Sep 21, 2014

Might be a build up of crud inside the cylinder. Running it a little after tightening it down may give you a few more clicks. On the rear hangers, are you pulled all the way up in the slots?

As the rasp bars and concave wear, you will get wider clearances than the book says. even with new parts, I can't get mine nearly as tight as the book says I should be able to but it still threshes fine.

tweedler · Sep 21, 2014

Thanks RG

Rasps are fairly fresh. Concave looks in good
order too. Your point about not getting clearances
but threshing fine is comforting. The rear hangars
are almost full up in the slot. There is no way I
will get 3mm at the rear rasp to concave. What
are you cutting (small grains for me), I just
think that with such large drum-concave clearance,
I'll lose half the crop !

Appreicated
Tweedler

flying belgian · Sep 21, 2014

Don't know if it is the same as a 750 but on my 750 there were some adjustable eye bolts for the front of the concave on each side of cylinder. Since the cab lever did not have enough travel to adjust close for small grain and far open for corn, you had to make up the difference with those eye bolts. Previous owner must have harvested corn last with your machine so has the eyebolts opened way up. Left side eye bolt was a bugger to get wrench on. You will need to cut a wrench down to about a 4" handle to adjust it. Also there is a access window on LHS make sure you adjust them evenly.

RGMartin · Sep 21, 2014

In the last year it has run Oats, Wheat, Rye, Corn, and Beans.

On the small grains, I just cranked it all the way shut and ran it.

Brokengun · Sep 21, 2014

I have owned a 550 for years and ran 510 MF before that and I have never heard of the concave settings being in metric. I would set the front at #5 or 3/4 and set the rear at 1/8" then set your cylinder speed and see what happens after the first round.

Set your cylinder speed starting at the book and set your sieves by the book.

If you grinding your straw slow down your cylinder speed. If your leaving grain in the head then speed up the cylinder before you close down the concaves. If your running in heavy straw and you close the down the concaves to much you will plugg off.

tweedler · Sep 22, 2014

Thanks Flying B
Pretty sure there are no eye bolts for the front of the concave as you describe on the 750, like there are in back but I'm heading out now to look. Seems like removal of both wheels (certainly the left) and left mudguard will be in order. Fingers crossed.

MF500 COncave Adjustment

tweedler

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RGMartin

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tweedler

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flying belgian

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RGMartin

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Brokengun

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tweedler

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