Tillers, anyone?

This forum is for the Fordson New Major, including the Super Major and the Power Major.
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case680rob
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Tillers, anyone?

Post by case680rob »

For some time I have been looking into buying a rototiller/rotovator to put behind my Fordson. I have a ‘61 FSM and it runs well. It is equipped with the Howard Deep reduction under drive so ground speed will be right. How much tiller can I run? I’d like to go at least 6’ so I can get out to the width of the tires, can I go 7’? My soil is sandy-loam river mud with occasional gravel and clay mixes.

I am mostly interested in the older Howard Selectatilth models that have the ability be re-geared for low and high speed.

Anyone out there with experience running tillers behind these old beasts?

shepp
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Re: Tillers, anyone?

Post by shepp »

Hi

We have many moons ago run 5 foot Rotavators on early Super or Power or ordinary Majors that are geared to run at 1200 engine rpm to give 540 rpm PTO speed, but ALWAYS with a raised PTO unit, so that the engine then ran at 1600 rpm to give 540 rpm PTO speed. However we never had any tractors with the Howard reduction box and sometimes the forward speed even in first gear at 1600 rpm was too fast. Later models of the Howard rotavator with the Selectatilth gearbox gave other options. Many at the time these tractors were current models did not use raised PTO units and an occasional tractor would suffer from PTO gearbox failure, which you want to avoid. We never had a PTO gearbox failure ourselves but have bought in tractors for re-sale that had smashed PTO gearboxes.

As you have a Howard reduction gearbox in the tractor, I would suggest you get a Howard Rotavator with the Selectatilth gearbox. Set the gears so that you get the minimum rotor speed at any given PTO speed. This will allow you to run the engine up faster than 1200 rpm and still not have an excessive rotor speed. At the same time the Howard reduction gearbox in the tractor will enable you to keep forward travel speeds low. The higher shaft and gear speeds in the PTO transmission achieved as a result of having higher than 1200 engine revs doing this will lead to reduced torque stresses in those shafts and gears which will translate into reduced shear stresses in the PTO gearbox and main gearbox casings. As you may be aware, the only real weakness that the Major/Power Major / early Super Major had was that the lugs carrying the intermediate gear in the PTO gearbox could shear off under heavy continuous or surging load leading to failure of the PTO drive and other damage in the main gearbox. The NP Super Major did not have these issues, one reason apart from having a heavier PTO gearbox case was that the engine ran at 1473rpm to give 540 rpm at the PTO so the PTO shafts and gears were running faster and the torque loadings were lower resulting in an additional benefit of reduced shear stresses in the gearbox cases. The main gearbox ratios in the NP tractor were also different so the tractor had slower and better spaced forward travel speeds.

The other but much more expensive alternative is to find a raised PTO unit for the tractor, this is geared down and allows the tractor to run at 1600 engine RPM to give 540 rpm at the raised PTO output shaft - but they are currently making around a thousand UK pounds IF you can find one!

At least with a reduction gearbox in the tractor and a Selectatilth gearbox you will have this option.
1946 E27N, 1952 Major Diesel, 1959 Power Major, 1962 Dexta, 1962 Super Dexta, 1963 Super Dexta NP, 1964 Super Major NP, 1965 Super Dexta 3000, 1966 Major 4000, 1967 3000 PF, 1994 5640,plus Basildon built NH.

case680rob
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Re: Tillers, anyone?

Post by case680rob »

Great information! That said, would a 6 or 7’ model be operable with a FSM? I did see a 7’ that was built for 1000 rpm PTO speed which would go well with overrunning the PTO to reduce torque demands.

Ideas?

shepp
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Joined: Thu Oct 06, 2011 8:24 pm
Location: Lancashire

Re: Tillers, anyone?

Post by shepp »

Hi

The engine is governed at 1800 rpm so the maximum PTO shaft speed you could achieve would be around 800rpm which would be too low for a 1000 rpm system and would in fact throw up the torque stress problems you want to avoid.

If you are careful you should be OK with a 6 foot model. The breakdown of soil is not achieved by increasing the rotor speed excessively, it is achieved by careful use of the lid. Make a first pass with the lid either fully or partly up to produce a rough tilth. Lower the lid partly and go through again. If necessary after this put the lid right down so that it drags on the soil surface and go through slowly again - the lid throws the larger lumps back into the mix to be chopped again but a pass with the lid down will demand more power from the tractor.

Your tractor will let you know with too much black smoke if it is being overloaded!
1946 E27N, 1952 Major Diesel, 1959 Power Major, 1962 Dexta, 1962 Super Dexta, 1963 Super Dexta NP, 1964 Super Major NP, 1965 Super Dexta 3000, 1966 Major 4000, 1967 3000 PF, 1994 5640,plus Basildon built NH.

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