Size does matter! The thing about how to choose the length of the PTO shaft
Many customers ask us how to choose the PTO shaft length. It’s important that it doesn’t get damaged quickly – otherwise you’ll be throwing money down the drain. Although you can find standardized rollers on the market, the length of which can theoretically be matched to different machines, in reality it is not that simple. In this article, we will tell you more about it.
How to choose the length of the PTO shaft?
Let’s start with the fact that not every tractor will have the same PTO shaft length. This is because the end of the beams to the beginning of the shaft is not identical in every vehicle of this type. So how do you measure this length? Shaft manufacturers specify it in units of L min and max, where L min is the length of the shaft when assembled, and L max is the length of the non-working shaft.
To begin with, it would be necessary to first hook the machine in 3 positions and lift and measure the shaft as much as possible from the bottom, from the top and in the position opposite the end of the rollers in a line. After measuring these 3 positions, choose the shortest distance between the PTO ends of the tractor and the machine. Then you need to slide the shaft as far as possible and measure from the center of the cross-bowls. The dimensions must match. As for suspended machines, the length of the shaft should be enough to connect the tractor to the machine in the lowest possible position.
Always fold the milled shafts in one position (they are so milled that it is impossible to do otherwise). Then the fixed ears of the shaft hitch are opposite each other -. As for the lemon-shaped roller, on the other hand, this aspect is irrelevant, because no matter how you turn such a roller, the ears will always come together.
And how to fit the crossbars to the rollers? Here it is necessary to measure the diameter of the bowl and the spacing of the bowls. Not all crossbar replacements should be done by yourself. Sometimes a hydraulic press is necessary when changing the crossbars. Because of the shafts of the front drive, so as not to damage the Crossbar. After installing the cross member, the joint should walk lightly without any resistance.
If you have a cutter, you need to buy a roller of the length you need, because the cutter usually does not cover the entire pipe but only the ends. As you shorten the shaft, you need to shorten one and the other by the same amount.
The issue of housing
What about the housing with the chains hooked up? When it comes down to it, different customers do things differently, mostly tying chains to the tractor so that the casing spins – one to the machine, the other to the tractor. If the cover is cracked, it is imperative to replace it for safety. A damaged roller cover can lead to “catching”, for example, a piece of shirt, and this risks a serious accident, even fatal.
Shaft power
What about the shaft power itself? If we adjust it, it is dangerous to choose a lower power than the power of the machine. For example, if you are going to put, say, a 250 Nm shaft on a rotary mower, the rotary mower will be damaged. If you select a higher power than the device has, it will be destroyed. On the other hand, if the shaft power is higher, it will not interfere with anything, unless clutches are required – this is when overloading the machine leads to damage. For example, this occurs when, for example, a hay rake encounters cow feces during operation. Then there is a lot of loading, and the angle boxes are quite fragile. That’s why the shaft has a latching safety device that, if a heavy load occurs, the machine stops spinning and the tractor runs, while the shaft spins. Without a clutch, the shaft will continue to spin until the gearbox is damaged. Which clutch should be selected for the shaft? This is already stated by the manufacturer in the machine instructions. We will tell you more about this soon on our blog.
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