This is a laser head with air-assist . The laser head is design for focus lens with 15mm/18mm or 20mm in diameter. It fit in a20mm diameter reflection mirror. By including a O-ring with this head, lens of 15mm,18mm, or 20mm can be used! This is a GREAT replacement for stock K40 laser head which comes without air-assited
Air plug outer diameter: 5.5mm
Mounting plate cut hole requirement : 14.5mm in diameter
Suggested tubing: 5X8 Silicon Flex Tube for CO2 Water Cooling
Great laser head
This is a great price on this! This replaced the original head and air assist nozzle on my DIY laser. I always had problems getting the air assist nozzle aligned correctly. Not only does this provide more clearance between the nozzle and the cutting surface alignment of the nozzle is effortless. I highly recommend this!
Very good upgrade, but lens position altered
A very reasonably priced upgrade for the standard laser head with very good build quality. I only have two remarks, which resulted in me deducting a star from this rating: 1.) Changed lens position: With this laser head the lens is positioned about 8mm higher than in the standard head. My machine has a fixed table height, so some change needed to be made in that aspect as well. 2.) Nozzle could be longer: With the standard lens (50.8mm focal length) the clearing between nozzle and material is about 22.3mm. Still works pretty good with a 60L/min comprossor, but would work even better with less clearing. Still a "must have" upgrade for the cheap chinese K40 machines ;-)
Great upgrade
Easy swap out. I used the coiled hose that comes with the airbrush compressor that Harbor Freight sells. Works great. If your K40 came with a 12mm focus lens then order a 18mm HQ lens at the same time. Better fit and more power delivered to your work.
Must have !
I'm using it with this lens: http://www.lightobject.com/Improved-18mm-ZnSe-Focus-lens-F508mm-P206.aspx With stock lens and without air-assist it's almost impossible to cut anything, after a quick mirror alignement (to fit with this new head) I was able to cut 6mm plywood with my poor setup (weak air compressor, quick mirror alignement, clearance almost ok, etc...) This head change a lot and is a great improvement ! Also it looks nice and professional !
Update: Works great once you figure it out.
Works great once Marco pointed out that the threaded section unscrews from the mirror holder. Don't get confused like me or Marco will yell at you too! :) Reply from LO: Separate the center piece from the rightmost module and it will fit into the 14mm mounting plate!