# Mill issues and Solutions



## Degen (Dec 7, 2022)

Thought I'd share a several solutions that I've done over the years to my mill, Busy Bee Craftex CT054 small knee mill (now a Craftex CX603, Grizzly G0731 or the King version of it, or any other mill on where the head rotates left and right).

The first is that the tip of the spindle to table can depending on tooling, tool holder, tool and work hold down (vise) can be too small. Even full size knee mills run this issue.  Add 6" approx in a head riser (not much more as it can leave your cutter hanging in free space with the knee at highest or not enough to not make it worth the effort).  I made mine of 4041 round solid.  The hardest part will be keeping the turned surfaces perfectly parallel (less than a 0.0001" over 6") as errors here translate directly to head nodding.

The second I just found this recently is preventing head rotation left-right inline with the Y-axis. Full size Bridgeport styles use a ring gear type alignment system that prevents rotation aside from clamping.  This smaller mills don't.  So....in use, the head rotates enough that your z axis drifts from vertical over time (CNC usage as accelerated this for me.  Solution, add an adjustable support strut, which does two things, makes traming easier, and once locked down greatly reduces (if not eliminates) head rotation.  My feeling this is a must if you have a small mill as 4 clamping bolt are not enough.


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## DPittman (Dec 7, 2022)

Degen said:


> The hardest part will be keeping the turned surfaces perfectly parallel (less than a 0.0001" over 6") as errors here translate directly to head nodding.


How do you achieve this? I would like to eventually make a riser for my 6x26 mill also.  I have a solid chunk of 4140 that I plan on using.


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## boilerhouse (Dec 7, 2022)

Can you post photos of the modifications?


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## Degen (Dec 7, 2022)

That tolerance is achieved with trial and error and measuring both on and off the lathe (it was done on the Logan in a 4 jaw chuck).

Surface plate and 1/10 indicator measuring on the edges on the cyclinder ht.

As to look, first the riser, second the brace (only the top but the bottom is similarly mounted on the column).


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## Degen (Dec 14, 2022)

Here is a pic of dual parts cut on the machine, as a reference for they are in dual 4" vises (BB), cut at 20ipm, 0.050" depth upto 1/2" wide cut in single pass otherwise 30% of cutter (1/2 endmill) 3000rpm and full flood coolant.

And you guys wonder how I create so main chips


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