General Stuff

Backward Laser Engravings
The laser unit engravings on the Y axis of the Sherline mill are backwards! The numbers increase or decrease opposite to the way the tool moves. I brought this issue up on yahoo groups to confirm and it is correct but I don't know if it has been changed by Sherline.  Disregard them. I put a piece of "trim sheet" (black vinyl sticky covering) over my axis to cover them up. I hated to do this but they kept messing me up. Hopefully Sherline is getting this fixed.
 
Parallel Leadscrew
I found the edge of the Y axis table not parallel when I converted to CNC. This edge was filed down until I noticed no movement (vertical or horizontal)
at the tip of the leadscrew while tightening down the stepper motor mounts. Check yours for minimal binding.

Z-Axis Leadscrew
I also found the Z axis mount not to be perfectly parallel with the axis. I put a thin shim under the stepper motor mount (a broken piece of single edge razor blade) and made sure the leadscrew did not move while tightening the bolts. Try to keep the movement smooth through out the axis.

Making Sherline Manual Rotary Table
CNC Capable (4-6-01)

Above: Pictures of how I connected a Sanyo Denki Stepper to my manual Sherline rotary table. I made these mounts manually even though I have the CNC setup. Sometimes it's just easier to make a part on paper than the computer :)  I used the existing lower mounting holes located on the bottom of  the table to mount a bracket  to hold a "motor plate." This plate is then supported at the top with a small 90 degree angle, which is tapped and bolted to the table, to support the motor's weight. The motor is then directly connected to this plate via turned standoffs and 3 mm screws. The motor is connected to the table's leadscrew with a turned and tapped coupler. Overall it works great! I had to play around with the mesh of the gears to take out as much backlash as possible. Make sure you CHECK for any metal chips in the gear mesh and re-grease the gears! Last thing you want is a metal chip binding up your expensive table! The motor connector, behind the motor,  is a normal radio shack 5 pin DIN connector (can't find these anymore). I used a 3/8" piece of aluminum, put a taper on it to make it look nicer, polished via steel wool #0000, and drilled out the center. I then bored out the connector to 3/8"  and glued the 2 pieces together!  Cheap, effective, and looks nice :) Why such a large stepper you ask? Well, being the curious one I opened this stepper to see how it worked, smiling? Been there huh :) I learned very quickly not to open a stepper motor or at least not to pull one apart. Magnetism was lost in a second and I think the torque went to 1/2. The motor is weaker, runs hotter and slower.  Instead of throwing it away I figured, heck, I'll use it on the rotary table and the CNC 4th axis was born :) Since then, I have changed it out to a smaller stepper around 75 oz/in. So what did I learn: DO NOT OPEN UP AND PULL APART ANY STEPPER! YOU HAVE BEEN WARNED :-)

Lighting the Head and Making it
Easier to See Your Work!
I personally suggest this modification

In an attempt to decrease as much weight on my mill's headstock I rewired the control box normally found on the mill to the back. It was A LOT of work but not only is it lighter, I can see my work MUCH better. If you plan to do only one modification (other than the safety light which I don't consider an "option") this is the modification I would do! I have also taken the 2nd part of the pulley off to decrease more weight  and have turned it smaller. Adding to this, I made a new larger motor pulley to increase my rpm. Right now with the CNC Setup, I have a spindle on/off light and a main on/off light.
Please see below how to add your own main light. 

Make sure you're very comfortable with wires and soldering before attempting this modification!

If you're not comfortable with wires don't try this, don't ruin your perfectly working mill! I rewired the speed control, spindle on/off LED and the main on/off 110v light to the plate that the control box is originally mounted from.

Here you can see that the entire control box has been removed and mounted to the rear of the machine. The second smaller box is the power for the 12v halogen. The head is much lighter and the work is MUCH easier to see, a huge advantage!

To help out my Z-axis stepper, I added simple springs to aid in pulling up the weight of the headstock. It helps out quite a bit. In this picture you can also see a bright yellow LED (where the control box normally mounts) which tells me the spindle is on via CNC. To make your own board Click Here.

Another view of the wiring. Again, I think this might be the BEST modification to do. You can't imagine how much better you can see your work! Again, make sure you comfy with soldering and playing with wires.

Fancy Handles! (1-28-01)

Add a Safety Light for your fingers! 

Picture to show layout of pins For more detail on this speed control please visit  KB Electronics

It is very easy to leave the Sherline mill or lathe ON with the speed control setting at low thinking it is OFF. I found myself thinking the lathe or mill was OFF only to realize days later that it was, in fact, ON. I also found myself changing tools with the equipment ON, again thinking it was OFF! Adding an indicator light is very easy. Just buy a 110 volt indicator light from your local Radio Shack. They come in a number of colors, pick the color you like. Drill a hole in the plastic case and connect the wires directly to L1 and L2 on the PC board. NOTE: This is LARGE L1 and L2 NOT small l1 and l2. That's it. Now when the lathe or mill is ON you will have a light to let you know. Quick, cheap, and most importantly, SAFE.

NOTE: Connecting SMALL l1 and l2 will cause the spindle to turn off! There is a built in on/off in the board! 
Wanna make it turn on/off via G-Code? Learn how to HERE.

Y-Axis Wipers, Less chips in the Base!

By far one of the most things I dislike about the the Sherline mill is the lack of leadscrew covers to protect the Y-axis. For now, I have added leadscrew wipers to keep the chips out of the nut and inside the Y-axis base. This is a spin off of Sherline tip# 17, thanks Larry (click HERE to see many other great Sherline tips too). Reason it's modified is to prevent the loss of any axis tavel.

After removing the base, I drilled the largest possible hole about 3-4 mm deep with a hand drill. This is the rear of the Y-axis base.

I cutoff a piece of rubber from a washer and shoved it into the hole. Here you can see a piece of the washer in the hole and the full rubber washer too. It's a nice tight fit.

I turned an aluminum "retainer ring" to keep the rubber ring in the hole. I simply made it "just the right size" so the fit is very tight. A tiny amount of blue Loctite helps hold it in!

Adjustable Z-Axis Backlash Control for CNC
 (same design for the Manual or CNC Lathe)
The original design!
I see that Sherline is now offering this way of backlash compensation but took credit for it..
Craig was kind enough to send me these kits for free for this idea! Thanks Craig!

I finally figured out a simple way to control backlash on the Z axis. Backlash, what a pain! First, drill and tap two holes, one in the saddle and one in the nut (length wise).  The nut has to go on upside down for this setup. The indentation for the "ball" that fits in to lock the manual mill faces up. I also put the nut on the bottom of the saddle so it doesn't unscrew when the Z axis is at the top.

Bend a piece of aluminum or steel to make a bracket. Drill two holes that are LARGER then the bolt you plan to use for full adjustability. I drilled/tapped for a 3 mm bolt. Here is the setup thus far. It is pretty easy.

Here is an underside view of the entire assembly. Move the nut to compensate for backlash and then tighten it down. That's it!

Top view of adjustable Z-axis backlash. Please note, this same setup works on the lathe except you have to grind the nut lever just a little so it does not hit the base of the lathe. Enjoy.

Questions? Comments? Ideas? I would love to hear from you!
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