These plans are for the Sieg C2 Mini Lathe CNC kit.
The bores can be either CNC milled or bored out to size, whether it being a boring head or boring bar in a lathe using a 4 jaw chuck.
all tapped holes other than the 4 on the motor plate can change size to accommodate either what you have on hand or want to do.
The depth of the motor recess on the motor plate can be deeper but that is a minimum to clear the motor or even all the way through.
All standoffs must be relatively tight tolerance within about .002" so that the two plates are as parallel as possible for a good coupling.
The standoffs are a tube, big enough ID for the screws to fit through and small enough OD so the coupler doesn’t hit.
The standoffs that I have used were 3/8 tube and 1/2" tube with 1/4" diameter hole or a little larger.
The length of the standoffs are dependent to the coupler, they should be .4" to .5" longer than the actual shaft coupler but all the same length.
When I made the slots, I used a 1/8" end mill but you can use bigger or smaller, slitting saws or even skip the slots and use set screws.
There isn’t much room for set screws in the x-axis mount.
Parts Needed:
5/8x1.5" 6-8" Needed (more if you make a mistake)
1/4x2.25(1/4x2.5 is all I could find) 6-8" Needed
8x Tube or round stock for standoffs I used 3/8x.035 wall
8x Screws to attach Motor Plates and Axis plates through standoffs I used 2.5" 1/4-20 flathead
8x Screws to attach motor, 10-24 x 1/2 socket cap
4x 1/4-20 x 1.5" long socket cap screws for clamping.
Construction:
First you should mill the pieces to size, if you can it's best to use a vice stop so you don’t loose your zero.
First, we will start with the motor plates: These ones are pretty simple for the most part.
Because I couldn't find any 1/4x2.25" flat bar, I had to go with 1/4x2.5" flat bar and mill down the ends. I cut and milled my pieces down to 2.25x2.25" Make sure to cut the parts about 1/8” longer so you can mill off the ends flat and true.
Now the rest of the operations should be done in one mount making sure the bolt hole circles are concentric with each other. If everything is dialed in on a DRO it'll be easy, otherwise just take it easy and be careful.
First thing I do is drill a 1/2" hole through the center, dead on and call that zero if you want, otherwise stick with the corner as 0,0.
Then drill the rest of the holes according to the drawings supplied.
The outer holes need to be drilled and tapped for 10-24 socket cap screws. For 10-24 tap, you need a #25 drill
The next operation could either be one of the easiest or most difficult,
If you have a boring head, make sure its dead on center of the part, you could do one of two things here:
Bore little more than .06” deep to clear the motors protrusion or bore all the way through and it will clear regardless.
If you bore all the way through, it wont be any better or worse than boring only the step.
This bore here is for alignment of the motor,
It must be bigger than the 1.5" diameter of the motor but preferably not much more.
The bore should preferably be not much more than .005" oversize if you can, but a little more shouldn't hurt.
Now onto the Axis mounts:
Essentially both the X and Z-axis mounts are the same, at least the operations are very similar.
Make sure to cut the parts about 1/8” longer so you can mill off the ends flat and true.
The first thing you should do is drill the end holes for clamping, the tapped part is only half way though, so be careful with that not to drill the clearance hole too deep (should just be .75" deep)
Next, Flip the part for the drilling and boring operation. Be careful to flip it right because the clamping holes are closest to the face that gets the bore so they can clamp properly.
In this operation you will want to drill the 4 tapped holes for the screws that pass through the standoffs and bore the bore in the same mounting for best results.
The four 1/4-20 tapped holes should be drilled with a #7 drill.
You will want to either drill and bore the mounting hole to size or drill those 4 holes, order of most of these operations is not important.
The depth of the mounting hole isn’t quite so important as the concentricity of the bolt hole circle (the 4 holes)
Try not to make the diameter over by more than .005" If you do it still could be ok.
The final operation will be slotting the axis mounts. This can be done many different ways, you can even use a band saw to complete this operation. If you choose to use a horizontal band saw, make sure to compensate for the angle that the blade will be at when you make it to the final depth.
I have a few times clamped a drill press vice in my band saw vice for doing these kinds of operations with decent results.
I do suggest milling the slot, it is long and tedious to do with an 1/8" end mill.
If you have a larger machine (not desktop mill) you could use a key cutter or slotting saw
Now besides tapping and deburring, you’re done with these pieces, Congratulations.
I hope you enjoy your kit, Please send me pictures of your completed retrofit.
If you have any questions or concerns, feel free to contact me.
Jon Fettig
Owner/operator
JFettigmachines.com
orders@jfettigmachines.com
Disclaimer:
This is for educational purposes only and Only qualified persons should attempt to make or install these devices.
I do not recommend or endorse modifying or changing any machinery from manufacturer’s specifications.
There is no warranty written or implied, I take no responsibility for destruction of equipment, injury or death.
These plans are for personal use only. Do not attempt to sell or make and sell this product.
maplegecko