DIY garden shredder

Recommendation points

• Types of garden shredders, main units and elements
• Cutting systems
• type of drive
• Drawings of various designs of garden shredders
• Hammer Grinder Blueprint
• Cutting tool – circular saw pack
• Double Roll Shredder
• Making a garden shredder with your own hands

Let’s take a look at the different types and designs of garden shredders for branches, chips, grass and grains that can handle any kind of plant waste. For you, we have compiled a selection of drawings and instructions for making a DIY knife garden shredder.

The garden is always full of pruned branches, grass, tops and other plant waste. You can collect them and burn them, you can pile them in a huge pile in the hope that someday you will get compost, or you can prepare raw materials for quick organic fertilization, for introducing chips into the soil in order to improve its structure, you can get excellent mulch or fuel for the boiler … For this you need a garden shredder, which you can buy, or you can do it yourself.

Advice! Protect your hands and eyes when using the shredder, especially if you are shredding solid waste. Glasses and leather gloves will protect you from injury.

Types of garden shredders, main units and elements

The shredders consist of a cutter, drive, loading hopper and frame with sheathing. In addition, they can be equipped with a crushed organic matter hopper. From auxiliary means: a pusher and a sieve, which is used to obtain a certain fraction of chips. The sieve residue is sent for re-grinding.

Garden shredders are classified by type of cutting system and type of drive.

Cutting systems

Commercially available chippers may have cutting systems:

• roll – branches and bushes;
• hammer – thin branches;
• milling – solid plant raw materials;
• with a rotating turbine – thick branches;
• knife – universal;
• trimmer (fishing line instead of knives) – grass, tops.

1 – hammer grinder; 2 – milling grinder; 3 – grinder with milling and turbine knives; 4 – knife disc grinder

There are other designs as well. For self-production, knife and typesetting from circular saws are suitable. The most common are knife, and the knives can be fixed on a massive disk in two, three pieces or more, or rotate towards each other in a two-roll design.

type of drive

Garden shredder drives can be powered by electricity or use two- and four-stroke gasoline engines. In practice, when making the unit with your own hands, they use an engine from a walk-behind tractor, which is idle for most of the year, or remove the motor from unnecessary household appliances. The main thing is that the power is sufficient – not less than 1.1 kW. If there is nothing suitable, you can buy a new engine, but in this case, the benefits of a homemade shredder are no longer so tangible compared to a purchased product..

Some shredders that process extremely soft raw materials, such as succulent animal feed, may not have a drive and work from human muscular efforts. Below are the drawings of shredders that you can do yourself.

Homemade hand shredders. A – double knife grinder: 1 – knives; 2 – shear plates. B – multi-knife chopper of greens: 1 – knives; 2 – counter plates; 3 – base frame. B – root crop shredder: 1 – shell; 2 – bearing; 3 – drum; 4 – crosspiece; 5 – handle; 6 – end wall of the body; 7 – shield; 8 – pitched board of the tray; 9 – stand; 10 – side wall of the case

In the first picture, the knives are made from old, one-sided sharpened saws, in the second, the knives and plates are made from the saw blade. The knives have beveled teeth, like a saw, with a pitch of 5 mm. Both shredders are equipped with long handles for ease of effort. The working part of the third design is made in the form of a drum with notches, the sharp edges of which protrude outward.

Drawings of various designs of garden shredders

Consider several designs of shredders that you can assemble yourself.

Hammer Grinder Blueprint

The hammer grinder can crush branches, straw, corn stalks, grain.

1 – loading hopper (sheet? 1 mm); 2 – edging of the feed hopper neck (corner 25×25); 3 – damper / latch (sheet? 1 mm); 4 – M6 bolt for screed (8 pcs.); 5 – framing of the loading hole in the housing (equal angle corner 25 mm); 6 – hairpin М8 (8 pcs.); 7 – outer drum of the body (pipe O 270×6); 8 – stator with grooves (pipe O 258×6); 9 and 20 – hammers and spacer washers (sheet? 3 mm, hardened to HRC 45–47, 72 pcs. And 70 pcs., Respectively); 10 – bolt O 3 (4 pcs.); 11 – M20 nut with a spring washer; 12 – hammer axis (circle O 22, 4 pcs.); 13, 14 – piping piping (equal flange angle 25 mm); 15, 19 – gaskets (rubber, sheet? 3 mm); 16 – M8 nut for flange fastening (8 pcs); 17 – hammer rotor; 18 – flange (sheet? 5 mm, 2 pcs.); 21 – retainer; 22 – drive shaft

Cutting tool – circular saw pack

A package of 15-30 circular saw blades mounted on a shaft – one of the options for the cutting system of the shredder. Some craftsmen point out that the saw teeth are quickly clogged with plant matter. Others argue that they have achieved good tool performance empirically by setting different teeth relative to adjacent saws. Since the carbide teeth are thicker than the blade itself, thin spacers made of metal (for example, washers) or plastic must be installed between the saws, and the whole package is clamped with nuts.

Pack of 15 saws on shaft

As a drive, you can use a low-power walk-behind tractor, pulleys and bearings – used parts from a VAZ car. The mouth of the loading hopper is a truncated pyramid, the outlet is small so that a person’s hand does not pass. It is better to make the frame for the shredder higher in order to remove the crushed raw materials less often.

Saw set on M20 hairpin

Side view

Double Roll Shredder

This shredder chops branches into lengths from 2 to 8 cm long, convenient for stoking a bath or a wood-fired heating boiler. Its design consists of two shafts with knives – 3-4 pieces per one shaft, rigidly bolted. Knives can be cut from the spring of a KamAZ or MAZ. If you find a bulldozer knife, it will work too. The shafts are fixed on massive sheets in parallel, at a distance sufficient for the knives to cut off the branch, but do not cling to each other. Free rotation of the shafts is ensured by bearings, and their synchronization is achieved due to a gear clutch moving with a belt (chain) from the engine. To drive this shredder, it is advisable to use a high-power engine, but at a lower speed..

If you want to create a mobile shredder, you need to provide wheel mounts on the frame.

Frame element

Axle and shaft

Shaft assembly

Arrangement of shafts on the frame

Shafts from a square billet for 4 knives

The video shows a chopper with gears: driven gears – from the MTZ shank, fitted to the desired size, the leading (gear for transmitting torque to the shafts) was found by the selection method.

Making a garden shredder with your own hands

The most structurally simple and inexpensive shredder can be made from a disc with knives attached to it, an engine, a frame and a loading hopper. You can grind the disc and knives yourself, order from a turner or buy parts in a store. The cultivator motor is suitable as a drive, and the frame and the loading hopper are easy to weld yourself.

Depending on how many knives are used and how they are exposed, the fraction of the resulting mulch can be different. The drawing below shows the basic design of such a grinder: a disc with four knives mounted vertically. Also, the design works well if the disc is fixed at an angle to the horizontal, and there are only 1 or 2 knives..

Assembly drawing: 1 – 4 knives; 2 – disc cutter; 3 – bearings No. 307

Operating procedure:

1. Buy, order or grind your own disc with knives. The knife sharpening angle is 35–45 degrees. The blade must have holes for the bolts to attach to the disc. It is important to correctly align the knives and secure them with bolts and stops.
2. Weld the frame, taking into account the fasteners for the drive and other elements.
3. Place the disc on the drive shaft and secure.
4. Weld the feed hopper and, if necessary, the receiving hopper of the chopped mass.
5. Collect all elements on the frame.

If the frame is installed on wheels, then the structure becomes mobile.

Grinding disc

Set of knives with fasteners

In the video, the master gives advice on the device of a homemade disc shredder.