Pulling an 8 foot disk

[Carykong]

I pull a two gang 7' disc with my antique Case VAC tricycle,about 15 hp, in first gear,ag tires,no problem in dry sandy dirt.

 

[slowzuki]

I just bought a 12 ft disc, big old IH unit. I had to use 4wd after the first pass, once the ground loosened on the hills. Pulling with our new MF 5455 (about 10,000 lbs with the loader on, 85 hp)

 

[milkman]

I dug up this old thread because of some recent experience with an old pull-type disk I picked up recently. It measures 8 ft wide across the back sections, and 7 ft wide across the front so I guess it would be considered a 7-1/2 ft or so. First, off, it has been so long since I used a pull-type disk (20 years or so) that I had forgotten how much better they work than 3 pt models. I used this disk the last couple weeks on three different tractors. On my aprox 20 hp, Allis Chalmers C, I could pull it on previously disked gound in second gear (aprox 4.5 mph) at the second steepest angle setting. My aprox 30 hp, Ford 8n would handle it on previously disked ground in second gear (aprox 4.5 mph) at the steepest angle setting. My 43 hp, 4wd, JD 4120 seemed completely uneffected by the disk and would pull it with the engine at idle (6th gear, idle = aprox 4.5 mph), at the steepest angle setting in fresh-plowed ground. I ran it at that speed in 5th gear with the rpms up just a bit because I dont like to work my diesels at idle. Two things stand out here, first, 4wd makes a world of a difference on a disk and no implement I know of, except maybe a loader, benefits more from a driven front axle. Second, this disk is way undersized for my JD, but just about right for those other two tractors. This disk is certainly quite a find for $100, which also included two 3-section drags the guy threw in with the deal (good thing scrap steel has dropped 90%). What I really like about it, compared to the old Bissels I had long ago, is you dont even have to get off the tractor to change the setting. Just pull a rope and back into it to make it steeper with about 8 settings, or pull the rope and drive ahead to straighten it out for transport. It has a little green paint left on it so I think it might be a JD. Any ideas? Sorry, no digital camera here.

I think this is the same disc that you've got YouTube - Discing and you can see it's not cutting very deep at all, if it was the little BX would be stopped in it's tracks.

 

[JoeinTX]

wol,

The little disc you describe does sound like an old JD pull harrow that was often offered as a package deal with their moldboards/grain drills/spike harrows/fertilizer spreaders/etc. back in the 1940 and 1950s. It is exactly like the one Milkman has in the video in the link he posted.


It's a harrow for conditioning tilled ground rather than a true primary tillage tool. We've pulled ours with the Jubilee on several occasions and at minimum sweep angle the tractor had little trouble with it. As you say, when you get into any trouble you just trip the lever via the rope and pull forward/back up to adjust the angle and then keep going.


I've always considered it an 8' plow since it was intended to be used in conjunction with the JD drill which is around 8' boot-to-boot.

 

[FarmerJames]

I would like to ask a question in comparison to info I found at the CaseIH website. In their tillage specs for the tandem disc 340 they say the weight is 7982-15045 and they give the working widths at the top. Now lets just assume that 15045lbs is for the largest disc with a working width of 34'1". They give tractor hp requirements at the bottom of the spec sheet which is,

Engine Horsepower 8 to 12 hp/working ft. (20 to 29 kW/m)
PTO Horsepower 6.9 to 10 hp/working ft. (16.9 to 24.5 kW/m)

So if I go by their specs and multiply 12hp by the working width of 34.1 I have 409.2 hp requirement.
But if I go by CCWKen's formula(which I liked) multiplying the weight 15045 by speed(6mph) I get 90270. Divide that by 375 and it equals 240.72 hp. Somethings not right here. Either the tractor companies are conspiring different specs in order to gain bigger profits or CCWKen's formula is wrong. I would like to think the formula is not wrong because I am in favor of having less expense in tractors to pull equipment.
Can someone please figure this out for me? Thank you.
James

 

[flusher]

I am considering buying a M.F.#25, 8' disc. Does anyone know if a small 26 HP compact tractor can handle a disc of this size? My tractor is a Kubota B2620.

Way too small for an 8ft disc. My 54 hp (engine) Mahindra 5525 struggles with my 7.5 ft wheel disc (a heavy Krause KS1300 13 ft disc cut down to 7.5 ft) in soft soil. Go with a 5-ft tandem disc that your 3pt hitch can handle.