T3P3 Kossel Mini Kit

Assembly Instructions

Chapter 2 - Base Assembly

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201 Motor assembly - Parts required

Motor brackets x 3

Motor x 3

GT2 pulleys x 3 (grubscrews pre-fitted)

M3 x 8 socket capscrews x 12

M3 flat washers x 12

202 Fit pulley to motor

The pulley is fitted with the collar and grubscrew at the outer end of the motor shaft. This provides correct alignment with the idler at the top of each tower.

The top of the pulley should line up with the top of the motor shaft as shown.

The pulleys come with a grubscrew pre-fitted inside the hole. The motor shaft has a flat side - align the flat side with the grub screw. This firmly couples the pulley to the motor shaft. Tighten firmly (but do not overtighten) with 2mm hex key.

NOTE: Some pictures below and in later chapters still show the pulley fitted the other way round on the shaft - please ignore this difference.


203 Fit motor to bracket

Align motor with plastic bracket (shiny side down for aesthetics), with the cable socket on the right-hand side of the motor viewed from the bracket end (hidden in this picture).  Insert 8mm capscrews and washers and screw in with the ball end of 2.5mm hex key (in the order: screw head, washer, plastic bracket, motor). There is a groove in the printed part to reduce the angle of the key slightly. Make sure the screws go in straight - loosen and re-align any screws that that have gone in at an angle. Do not tighten fully with the ball-end.  Instead use the short leg.

Repeat for the other 2 brackets

204 Base assembly - parts needed

Motor bracket assemblies x 3

Frame extrusions 240mm long x 6

M3 x 8 socket capscrews x 24

M3 full nuts x 48

M3 flat washers x 24

205 Fit extrusions to brackets

Insert 2 capscrews with washers through the 2 bottom holes and very loosely fit 2 nuts. Note that the screw head is facing the motor (order: cap screw, washer, plastic bracket, nut, aluminium extrusion).

Slide an extrusion onto the 2 nuts. You may find it helpful to use a pair of tweezers or needle-nose pliers to rotate the nuts into alignment. Very loosely screwed on nuts makes this easier.

Slide the extrusion tightly up against the plastic and tighten the nuts just enough to stop it coming off.  They will be tightened fully later, after the whole base is assembled.

Repeat the procedure with the top extrusion, ……

and with the other 2 brackets.

206 Fit nuts - external

You cannot fit nuts into the side slots of the extrusions once the base is fully assembled. You need to fit at least 2 top and bottom to one of the sets, but we suggest you add them to all 3 sets,  and we provide enough nuts to do this.

The nuts can be prevented from sliding up and down the channels by by fixing them with a small piece of tape at the centre of the extrusion (optional).

207 Fit nuts - internal

In the same way,  add 2 nuts to each bottom and top extrusion on the inside.

208 Final Assembly

For each of the three assemblies; fit the 4 M3 x8 capscrews, washers and nuts as before.


Arrange the 3 assemblies in a triangle.

Slide one pair of extrusions onto the nuts. Do not try and slide them up to the second pair of nuts yet. Instead tighten the screws just enough to stop the extrusions coming off the bracket.

Repeat for the other 2 brackets, then loosen the nuts enough so that the extrusions can be slid up to the other pairs of bolts and nuts.

Align one pair of nuts, slide the extrusions onto them and tighten to keep them in place while you work on the others.

Once you have all the nuts in their channels, slacken them all slightly and slide all the extrusions fully home. Lay the base on a flat surface and progressively tighten all the nuts , first with the ball-end of the hex key…

and then finally with the short leg.

The completed base assembly may now be set aside while you get on with the top assembly.