The Kronos Robotics KRMx01 CNC

I have been using my old JGRO CNC machine for a while now and while I like the machine, it is time to take a look at improving and moving on to something better.  Most of the issues I have with the JGRO machine is its lack of rigidity.  I can cut but have to take things slow or I get enough flex that the part will be out of tolerance.  With that problem in mind I set out to find a new machine.  Now there are loads of plans for CNC machines on the Internet, some free and some that cost money.  I knew that I wanted to move away from a wood machine to something made from metal.  In the research that I have done, this led me to two choices that I was considering.  That would be the MechMate and the Kronos Robotics KRMx01 or KRMx02.  I wanted a machine that I could build that was within my skill set.  This sort of left out the Mechmate for me because I have very little experience with fabricating metal to the level that is required for that machine.  That left me trying to decide between the two models that Kronos Robotics have to offer.

KRMx01 or the KRMx02?

Both machine options from Kronos are pretty good.  The KRMx01 machine is a screw driven machine giving a good range of precision but at a slight sacrifice of speed and some other components that will need occasional adjustments through use and normal wear. For example, the nuts used to drive the machine are plastic and will wear and will need some occasional adjustment to compensate.  The KRMx02 is a very rigid machine designed for speed by using a rack and pinion system but at a loss of precision.  It was a tough decision for me to decide which machine to build.  In the end after having conversations with the designer, Michael Simpson, I selected the KRMx01 model for the precision with the option of making a couple of upgrades to the machine to make it better.

Making a good thing better.

Discussions with Michael of Kronos Robotics led me to a solution that at lease at this point in time fits my needs very nice.  The long term plan for my KRMx01 build will be to replace the Aluminum angle used for the bearing rails with ones made from hardened steel, and finally use the Z-Axis from the KRMx02 to provide more router support than the KRMx01 would give.  Probably the best solution of all would have been to build the KRMx02 with leadscrews instead of rack and pinion.  The gained speed of the rack and pinion does is less important than the precision of the leadscrew.  Beside talking with Michael, I bought his books on both machines.  Even if you are still in the research phase of your planning, these books are worth having in your library.  The KRMx01 book can be had as a free PDF download from the Kronos Robotics website, but buying a printed copy from Amazon with illustrations your can read is worth the few extra bucks.  I have images of all three books below and you can click on them to get a better view of them.  If you are interested in these books, take a gander at and check them out.

 Building the KRMx01 CNCUpgrading and Operating the KRMx01 CNCBuilding the KRMx02 CNC

I hope you enjoy the journey!