Kossel 3D Printer – Fasteners

Preamble

Following on from Kossel 3D Printer, here is a list of fasteners require and possible sources.

See also

Fasteners

Original List

This is the original list, as taken from Kossel 3D Printer

Additional items

M5 x 20 mm for the Kossel extruder

An M5 x 20 mm bolt is used in the Kossel extruder, to hold the bearing

M3 Washers for Sintron Idlers

4 M3 washers are required for each idler on each top vertex

M3 x 40 mm for Sintron Extruder holder

The Sintron kit uses one 40 mm bolt for the extruder stepper motor holder:

M3 x 8 mm for Sintron Kit frame

With respect to the Sintron Kit, the whole build uses M3 bolts. No M5 bolts are used for the frame at all. So, M3 x 8 mm bolts are required

and M3 T-Nuts, for European 2020 aluminium extrusion. If you are using an extrusion that does not take T-Nuts then you have a problem, as I did. Either, in order of preferability:

  • Do not use the Sintron kit
  • Swap your extrusion
  • Make the holes in the Sintron kit M5
  • Find a fat hexagonal M3 nut with the width of an M5 hexagonal nut.

For the endstops

For the Sintron kit, three M3 x 8 mm bolts are required, in order to secure the PCB mechanical switches and endstop holders to the frame. However, the types of nuts used depends upon the type of 2020 aluminium extrusion, in particular, the profile of the extrusion.

If the usual “European” profile is used then regular T-Nuts can be used. However, if you are using a profile that only accepts regular hexagonal M5 nuts, then other nuts need to be used, as regular hexagonal M3 nuts will not provide sufficient purchase on the aluminium. One solution is to use flanged nuts. See Fat hexagonal M3 nuts, with outer diameter greater than 6 mm.

Half M3 T-Nuts for 2020 extruded aluminium

To secure the PCB mechanical switches and endstop holders to the frame – actually, basically everything to do with the frame: vertices, spool, endstops, extruder, print bed, etc., mounting:

Full M3 T-Nuts for 2020 extruded aluminium

To secure the PCB mechanical switches and endstop holders to the frame

Full M3 T-Nuts for 2020 extruded aluminium, springloaded

To secure the PCB mechanical switches and endstop holders to the frame

M3 Flanged nuts

For an extrusion that only accepts M5 hexagonal nuts, which are 3.85 mm thick, and 7.85 mm wide,then flanged nuts seem appropriate. The height, or thickness, m, of the flanged M3 nut is slightly less than that of an M5 nut and the width, dc, is comparable to that of an M5 nut.

However, whilst they fit in the slot, being able to tighten them is another matter altogether, and they will just spin around, as they have no grip on the sides of the slot…

Flange Nut Dimensions
Flange Nut Dimensions

M3 Flanged Nyloc nuts

These may not fit the extrusion, unfortunately the dimensions for M3 nuts is not shown. The space in the 2020 extrusion is 4.4 mm and extrapolating the dimensions, the M3 height, k, is probably around 5 mm.

Flange Nyloc Nut Dimensions
Flange Nyloc Nut Dimensions

More Endstop madness

Endstop

There are only three endstops of the Sintron Kossel, compared to six endstops in the Bloomker Delta. These three endstops are for the minimum positions only, the max endstops are missing.
The Sintron endstops are really only spacers for between the mechanical switch PCB and the aluminium.

There are four M3 holes, in the Minimum Endstop spacers, but there needs to be an extra M5 hole for securing the switch to the 2020 extrusion.

The Bloomker guide uses mechanical switches, which are not mounted on PCB. 6 x M2.5 x 12 mm bolts are usd to secure the switches to the minimum endstops and the minimum/maximum endstops are secured to the 1515 extrusion using 6 x M3 x 8 mm

The sintron guide does not list or show, which size bolts to use, it only states that the PCB mounted mechanical switches and the endstop pieces are required.

 

Messages to Sintron

—–

Hi,

I have received the item, thank you.

However, I would like to know if you have a complete and detailed list of the fasteners (bolts, nuts and washers) required. I have a copy of your manual (construction guide) and that does not list the parts, and your eBay description of the full kit, only states that all required nuts and bolts are supplied, without going into detail.

In particular, I am having trouble with the rectangular endstops (which have four holes in them), for the mechanical switches. Are M2.5 or M3 bolts used to secure the PCB mounted switches to the endstops? What length are they? Also, what length and diameter (M bolt is then used to secure the PLA endstops and mechanical switches to the 2020 extrusion? I assume that it is an M5 bolt as they are used elsewhere when attaching items to the 2020 extrusion – what length M5 bolt is used. However, an M5 bolt will not fit through the mechanical switch holes, so is an M3 bolt used to attach the PLA endstops and mechanical to the extrusion
——-

Hi,

I have received the item, thank you.

However, I would like to know if you have a complete and detailed list of the fasteners (bolts, nuts and washers) required. I have a copy of your manual (construction guide) and that does not list the parts, and your eBay description of the full kit, only states that all required nuts and bolts are supplied, without going into detail.

In particular, I am having trouble with the rectangular endstops (which have four holes in them), for the mechanical switches. Are M2.5 or M3 bolts used to secure the PCB mounted switches to the endstops? What length are they? Also, what length and diameter (M2.5/M3/M4/M5?) bolt is then used to secure the PLA endstops and mechanical switches to the 2020 extrusion?

I thank you in advance.

Best regards

Reply

Hi

Good Day !

thanks for your contact.

we use M3 bolts + T-nuts .

i suppose the problem is , you don’t have T-nuts , right ?

T-nuts is used for 2020 extrusion.

with warm regards.

james

My replies

Many thanks for the reply.

I have two types of 2020 extrusion, with differing profiles: one that takes T-Nuts, and; one that takes regular hexagonal M5 nuts.

For the T-nut extrusion I have both M3 and M5 T-nuts.

However, the second type of 2020 extrusion takes regular M5 nuts. Regular M3 nuts will not stay in place, unless I can find some M3 nuts with a larger outer diameter, greater than 7 mm.

With respect to the M3 bolts, what are the lengths required? Are two lengths used? One length to secure the endstop switch and holder to the 2020 extrusion, and then another length to secure the remaining three holes? Looking at the diagram in your build guide, it seems as if only one bolt is used to secure the endstop switch and holder to the frame, is that correct? Are any other bolts used to secure the PCB mounted switch the the endstop holders.

I thank you in advance.

Best regards

and

Hi again James,

Following on from my previous reply.

Firstly, I have found that flanged M3 nuts will work perfectly, in the extrusion that will not accept T-Nuts.

Secondly, what I really am looking for is a list of the lengths (and dimensions) of the bolts used throughout the Sintron build. In particular the endstop bolts. Rather than having to iteratively deduce each bolt, a list of the bolts used would be very handy.

I thank you again in advance for your kind consideration.

Best regards,

 

 

 

Parts List for Johann’s Kossel

###Listed by Printer part/section:

####Fasteners

#####Extruder stepper motor mount

2 x M3 x 8 mm
2 x M3 nut (T-nut)

#####Extruder stepper motor mount

1 x 625zz bearing
1 x M5 x 20 mm
1 x M5 nut
3 x M3 x 8 mm
1 x M3 x 20 mm
1 x M3 nut

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