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How to build a screw wood splitter?

Contents of the guide:

  1. PTO power drill - what is it?
  2. Where to start building a drill splitter?
  3. Selection of the core drill splitter kit
  4. Choice of drill splitter drive
  5. Assembly of the drill splitter
  6. Operation of the drill splitter
  7. Summary

PTO power drill - what is it?

Drill splitter - is a device that uses rotary motion and a special design of the drill to split wood logs into smaller pieces. It is usually made of a base set consisting of bearings with a shaft, auger with a suitable diameter and a work table. Depending on the intended use, the splitter is driven by an electric motor with a pulley or agricultural tractor via a power take-off shaft (PTO).

The times when an ax was used to chop firewood are slowly becoming a thing of the past. More and more often in workshops, but also in households, wood splitters are used, i.e. tools that facilitate splitting even large pieces of wood. A properly constructed splitter will help us save a lot of work and time, and also take care of our health, because long hours spent chopping wood with an ax have a negative impact on our spine. If we heat the house with wood and treat several or several dozen cubic meters of wood each winter, a splitter is the perfect solution for us. If we choose the right drill for ourselves and the engine, and later we will construct a splitter based on carefully selected elements, we will receive a tool that will allow us to enjoy long winter evenings by the fireplace, without any unpleasant memories of hours spent outside with a aching spine and with an ax in hand.

Below is an accessible instruction that will allow you to build a wood splitter step by step. After reading this text, you will be able to choose the appropriate elements necessary to build the device.

Where to start building a drill splitter?

The most popular type is the drill splitter and we will focus on it here. The first step in building our splitter should be to define our exact needs. We know best how much wood we consume, what diameter the logs we process and how much time we spend on it. Knowing what exactly we need, we can proceed to choosing the right set. Depending on the diameter of the blocks we process, we need to choose the right drill. Below is a table showing the ratio of the diameter of wooden blocks to the size of the drill bit:

The diameter of the log Recommended minimum drill diameter
up to 20 cm 60 mm
up to 30 cm 80 mm
up to 40 cm 90 mm
over 40 cm 100 mm

Choosing a drill splitter base kit:

Knowing what our needs are and what we should be guided by, we can proceed to choosing the right set that we will use when building our wood splitter. Regardless of whether we are building a splitter for a tractor or an electric motor, we should choose the right set of bearings depending on the operating conditions:

The set is based on: Strength Application
Self-aligning bearings average home
Small hub high home / industry
Large hub highest home / industry

We recommend constructing a drill splitter on the hub, not necessarily large if we are not splitting on a large scale. The small hub has several times greater strength than cast iron self-aligning bearings, which translates into lower failure rate and lower costs of subsequent operation.

Choice of drill splitter drive:

Another thing we need to know is that wood splitters are usually powered by an electric motor or a tractor. If in our household we have a tractor at our disposal, we can use it to build our splitter, while in the absence of it a better solution seems to be the use of an electric motor.

If we choose the construction of an electric log splitter:

The engine power should be adjusted to the diameter of the drill bit, which we chose following the instructions described above.

Engine power up to 3kW 3-4kW 4-5kW 5-7kW
Recommended drill bit diameter 60 - 80 mm 80 - 90 mm 90 - 100 mm 150 - 170 mm
Recommended shaft diameter 30 - 35 mm 35 - 40 mm 35 - 40 mm 40 mm

If we have already chosen the right drill and engine, it remains for us to choose pulleys depending on the engine speed.

Engine speed

(low speed engine)

1400 2800
Gear ratio 1: 1 1: 2.55 1: 5.1
Small pulley (e.g.) inert or mounted
directly on the engine

78 78
Big pulley (e.g.) 200 400
Drill speed 400-600 550 550

We do not recommend assembling the  drill splitter on the 2800 rpm engine due to the large pulley diameter required for the drill bit = 400 mm, in practice it is cheaper to buy a new 1400 rpm engine than to invest in such an expensive pulley, which will additionally increase the size of our splitter unnecessarily.

For engines up to 5.5 kW, we recommend a set consisting of a 1400 rpm engine, a large pulley for a drill with a diameter of 200 mm and a small pulley for a motor with a diameter of 78 mm, which results in optimal cost of optimal drill speed = 550 rpm.

For engines over 5.5 kW it will be better to use a large pulley for a 250 mm drill bit and a small pulley for a 98 mm engine, thanks to which we will also obtain the optimum drill speed = 550 rpm, however, this will prevent the belts from slipping on engine wheel (with weaker engines this problem is unlikely to occur).

If we have a motor with a different speed, we should use the following formulas to calculate the pulley ratio and to choose the diameter of the pulleys, so as to finally obtain a speed of 550 rpm.

First, we should calculate the gear ratio:

Knowing the diameter of the small pulley and the gear ratio, we will calculate the large one as follows:

Knowing the diameter of the large pulley and the gear ratio, we will calculate the small one as follows:

For more information on pulley selection, see this article: 
How do you choose the right splitter pulley for your engine?

Check also our department with ready-made kits for the construction of an electric motor splitter:

Electric drill splitter construction kits

If we choose the construction of a drill splitter driven by a tractor:

Due to the high power of the tractor that we have at our disposal, the recommended drill bit diameter is 100 mm - 170 mm with a shaft hole of at least 35 mm. However, if we are only splitting smaller logs, we can also use another drill with a smaller diameter.

If the splitter mounted on the tractor is to be used for splitting so-called "Meters", we recommend choosing a base set based on a large hub with a stronger shaft with a diameter of 40 mm.

See ready-made kits for constructing a drill splitter for a tractor

If we do not yet know how our splitter will be driven or we need a universal solution:

In this case, we recommend that you suspend the purchase of a suitable set, or choose a universal set that is equipped with a pulley and an output for the PTO shaft - thanks to which it is adapted to work with an electric motor as well as with a tractor.

It should be mentioned that when using a drive from a tractor, universal sets are often used to drive additional devices. We connect them with V-belts and both devices work simultaneously.

See Universal drill splitter kits for tractor and / or electric motor

Assembly of the drill splitter

When we have all the elements, we can start assembling our wood splitter. Of course, the appropriate table will serve as the basis for the whole structure. We can make it ourselves, according to the attached drawing below, or use the table used in other tools, for example from a table saw. If we decide to make it ourselves, we can adapt it to the shape of our splitter, which is an undoubted advantage of this solution.

A very important thing is the safety wedge, which should be installed at the right angle to the drill bit. Its absence may result in a serious accident or destruction of splitting elements.

Drawing with instructions on how to assemble the wedge of the drill splitter

At what height should the drill be?

Contrary to popular belief, do not mount the drill bit at half the split log. When assembling the drill to the table, it should be mounted horizontally in such a way that the height of the drill bit is about 1/3 of the height of the split logs, however not lower than 0.8 of the drill bit diameter (see fig.). Thanks to this, much less force will be needed to split the log and the loads affecting the entire splitter structure will be reduced.

According to health and safety rules, every movable element of the device should be protected by appropriate covers. In the case of a drill splitter, we must install appropriate covers for the pulleys with V-belts and the drill bit. This should not be forgotten, because they are an indispensable element of the splitter and provide us with safety and comfort during work.

By completing all the elements and connecting the splitter, we can proceed to woodworking. Using the electric motor, we are able to work in closed rooms without any problems, which is a big advantage especially in winter, when the weather is not our ally. If we decide to use a tractor, the undoubted advantage is the mobility of the splitter and the possibility of using it directly in the forest from which we take wooden logs. Of course, we do not need electrical power then, which should also be written on the plus side of such a solution. Using a wood splitter remember about the safety and hygiene of work.

Operation of the drill splitter

If you want to know more about the safe use of the drill splitter, go to this article:

What should you remember when splitting wood? Log splitter operation and safety rules.


Although choosing the right elements and building your own wood splitter seems complicated and time consuming, by following the above tips we can do it quickly and efficiently. The time we devote to it will be a great investment and will pay off very quickly, because the processing of wooden blocks with a splitter will take much less time than before. Thanks to the use of a wood splitter, we save a lot of time and energy, which we can use in any way, for example, spending time with family by the burning fireplace. And this is what it is all about, so that various tools make our lives easier and allow us to draw as much as possible from it.



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