Laser Engraving Mandril for pens on Snapmaker Original

The Snapmaker (original) is a valued machine in my workshop and I have used it now with all three elements with a good deal of success albeit rather limited on the CNC side. I also produce pens on my woodworking lathe and have been wondering if I could design a jig to enable me to laser engrave the body of the pens with names etc. I have come up with a system that works and while I am sure it could be refined and improved, I am so far very pleased with the results. It is important to remember that the laser design has to be turned upside down in Luban! The number of passes depends on the type of wood being used for the pen.
The jig I designed and printed with a small slots to enable it to be exactly lined up the laser in the middle of the pen body. It is held in place with two screws drilled and threaded into the baseboard of the machine. It needs to be removed for 3D printing and CNC, so once it has been set up accurately, I have used a Sharpie marker to enable it to be replaced more easily.
The 3d printed part which allows for two bearings (Dia 22mm x 7mm x dia 8mm) for an 8mm shaft which connects to a 6mm shaft with a 5mm grubscrew onto which is positioned a 3d printed wheel that is driven round by the bed moving backwards and forwards. The blue tape on the bed seems to give good grip for the wheels. At the other end of the 6mm shaft is a second 5mm screw that holds the second printed wheel and locks the pen body in place ensuring it turns with the wheels/shaft of the jig.

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Any chance you’re going to post the files somewhere?

Components required for Snapmaker Laser Jig Pen Mandril

I have designed this for my Snapmaker Original which I have set up with a 3mm Borosilicate glass bed on the original Snapmaker bed but if you are not using a glass bed you could just increase the size of the wheels by 6mm to allow for this, I would think, or reduce the thickness of the base of the bearing holder by 3mm may be better. I have used:

Two 8mm x 22mm x 7mm bearings Amazon
Four M5 x 20mm Hex Socket Cap screws Amazon
One M5 x 25mm Hex Socket Grub screw Amazon
Four M5 washers
One Dia 8mm steel shaft 70mm long
One Dia 6mm steel shaft 48mm long
Design for Bearing Holder 3d Printed Tinkercad
Design for Laser Jig wheels 3d printed Tinkercad

The holes I have drilled and threaded (M5) in the baseboard of the Snapmaker are positioned to the following measurements. (see photo)
You will see under the Z axis I have a 3mm aluminium plate that I inserted to compensate for the 3mm glass bed I use on the Snapmaker bed held on by picture glass clips. There is as I have said a little lateral movement in the slots to allow the laser to be accurately aligned before tightening the two screws into the baseboard.

The two steel shafts need to be drilled and threaded accurately both ends with an M5 thread (quite tricky in the 6mm rod)
The 8mm diameter shaft needs to be threaded to over 20mm deep one end for the bearing screw, I also gave the 8mm shaft a very slight centre punch near the end of the outside of the shaft so it is a tight fit in the bearing. The other end of the 8mm diameter shaft is threaded in about 10mm for the M5 grub screw which is tightened in before the first wheel is positioned. Then the 6mm diameter axle is screwed on (this is about 48-49mm ie shorter than the pen blank). The pen blank is then slid on followed by the second wheel, washer and screw which is tightened to hold it firmly against the wheels. I find the blue tape on the glass bed gives the wheels a bit more grip
I hope this is all relatively clear. It seems to work for me – Good luck!! Feel free to message again if it is not clear.