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Komatsu ZR77 Blasthole Drill

Maker:  Weiss Brothers
Model No:  026
Scale:  1:50
Review Date:  July 2022

Weiss Brothers Index
Mining Equipment Index

Cranes Etc Model Rating
Packaging   (max 10) 8
Detail   (max 30) 26
Features   (max 20) 15
Quality   (max 25) 22
Price   (max 15) 8
Overall   (max 100) 81%


Komatsu ZR77 Blasthole Drill Video 
The box.
Where to buy
Mast folded.
Stair and fire suppression equipment.
High detail.
Loader crane and drill heads.
Plastic parts have an excellent colour match.
Angled drilling.
A wide load.

The Komatsu ZR77 is a blasthole drill used for pre-weakening rock in quarries before mass excavation. 


It comes in a Komatsu branded box.   Inside, the model is contained between a pair of factory-sealed expanded polystyrene trays. 

There were no defects or missing parts on the review model.

Two light bars have to be fitted and an instruction sheet is included.


The metal tracks are delicate and detailed, with some detail in the casting of the frames.  There are four stabilisers and these have large pads on the end of realistic hydraulic pistons.  Small air horns are located at each end.

At the front the operator's cab has wipers and sharp graphics.  The interior is one colour.  The walkways have metal handrails and excellent etched floors.  Access stairs have photo-etched stair treads.

At the rear there is fire suppression equipment, and at the front there is a loader crane which is entirely modelled in plastic.  Equipment and boxes along the sides are modelled in plastic, but the colour match is excellent, so it does not show.  There are large etched grilles on the heat exchangers, and on the inside the fan enclosure are to a high standard.

The engine area is detailed with the parts modelled in plastic.

The mast is a robust metal section which includes a toothed rack for the drilling equipment sledge. Handling equipment for the drill strings is modelled in plastic.

The drilling machinery sledge has hydraulic hoses running to the motors, and down to the engine
The drilling rod is metal with a plastic drill head.


The crawler tracks are free rolling and are mounted on spring loaded sprockets. 

The stabilisers work by unscrewing to lower them.  They have smooth piston faces.

There are three access stairs which can be raised or lowered.  One has an opening railing at the top.

The loader crane can be rotated, and the boom raised or lowered.  The telescopic sections are fixed and non-functional.

The mast can be set in the travelling position, and vertical for drilling.  It is also possible to set it an angle to replicate the angle drilling function of the real machine.  The supplied clip for locking it in angled mode is unsightly and most collectors will want to replace it with discrete pins. 

The drill motor sits on a sledge which travels up and down using the rack on the mast and is moved by using a supplied key.  However, the movement is limited to the upper part of the mast only, which is a pity

One drill rod is provided, and it can be posed drilling or on the handling equipment. 


This a very good quality scale model with a high metal content, and plastic used to provide detailing.

The paint and graphics are very good.


It is a large model which is fully priced.


This is a good looking model of a blasthole drill, and it can be posed in interesting ways.  It is an interesting addition to a mining model collection.


This model first appeared in June 2022.
Out of the box.
Metal mast.
Large grilles.
Detailed tracks.
The cab.
At work.
Impressive combination.