Sherline Lathe - Hand Wheel Extension

I added a hand wheel extension. I kept increasing the dovetail wedge pressure until I couldn't hardly turn the wheel so I was forced to get more leverage.

I think that the increased wedge pressure is essential for accuracy and the longer lever arm is great for tiny movements.

Sherline Lathe - Chip Guard

I needed a chip guard for a while but I'm particular, so when I finally designed it in my mind I started looking through the scrap metal bin and found the perfect aluminum extrusion.

I was looking for the smallest screen possible, not a whole machine type cover. The only way a minimum chip shield works is if it travels with the tool bit. The chips come off of the tool bit and go radially from that point. My machine is not set up to bathe the parts in coolant so I am only protecting myself from chips and oil spray. I use a needle point tip on my oil can (see in background) and put the absolute minimum drop by drop on my work.

I also wanted to attach it the same way as the tool holders. I leave the holder post in each T slot on the cross slide and spin out the Allen screw for each tool holder change so there is always a post available to the right or left of the tool holder post in use.

Sherline CNC MILL - Diamond Circle Square Test

The reason I went to the 20kg motor was because of the problems I was having with my millings specifically the motors skipping steps. The most important thing that I think I have done to mitigate this problem is slowing down the feed rate to 75% of top speed; 16ipm.

I performed a Diamond Circle Square test milling with the new motor and my 75% speed setting. The milling took about 30mins and went off fine.
I will provide all of the inspections data in a few days.

12.11.12
I am not a statistition but I do have a lot of inspection room experiance. This is the over - under graphic with dimensions for the DCS test.

I think that the circles are the most out of spec and because most of the dimensions came from a circle to a flat it is difficult to figure out. Ultimatley the X axis has most of the errors, Y axis is evry good.

The next time I run this test I will make two decrete runs: multiple concentric circles and multiple "concentric" squares.

Sherline CNC Mill - Motor Upgrade

Like so many Sherline owners I too had questions regrading the Z axis with respect to the motor capacity to handle the weight.
I found a 20kg - cm 6 wire motor to replace the 10kg - cm original equipment motor.
For installation I carefully reviewed the two spec sheets and  matched the color coded wires, making a temporary set up on a breadboard to test things at every stage.All went fine and the 1.8deg. motor was a perfect match but it turned in the wrong direction. Luckily for me the Mach 3 software has a reverse motor direction switch so with a few clicks I was up & running.

Unfortunately I did not get the dual ended version, I don't recommend this; you will want the hand wheel someday I'm sure.

Standardization is a wonderful thing isn't it?
I don't think I' am going to replace the other two axis right now but it would not hurt. 

Sherline Mill - Double wide T slot clamps

I have found that with so many of my larger milling projects that clamping the maximum area is preferred especially when using 12 lb foam. Another issue is that the exact center of my Y travel is located at the front edge of the cross slide which means that these bigger millings always overhang.

I especially do not like the extra step of bonding  the blank to yet another piece of material just to have to chisel it off later.

I decided to make a gang clamp that would combine both of the standard Allen screws onto one bar giving me maximum surface area and extending a little way over the edge for added stability.

The question was how wide is wide? The T slides are 1.5" apart so right off it became at least 3", the T slot to the edge is .615" so add them up and you have 4.230" total.

I took 5/8 x 1 C channel and cut off one leg; a perfect 3/8 height without any further work.

04.04.13
I made V2 of the double wides out of 1 x 1 x .12 aluminum channel.

The goal this time was to get a deeper bite onto the tooling foam groove that I cut using my biscuit joiner.

Sherline CNC - Y axis cover

The Y axis components are very exposed, I had been trying to figure out an easy way to to cover them but always came back to the bellows. Not wishing to fabricate them from scratch I procrastinated.

Last weekend I found the answer in the basement of one of our local estate sales... the bellows from an old camera or developing machine. For $3 I picked up the full bellows, a little wider than a perfect fit but I think it looks OK.

The neat thing about the bellows is that it came with end plates and there are enough sides to make both front and rear covers. This picture shows both my camera bellows and my thin acetate front cover too.

I'll get the front cover converted to the bellows ASAP.

Sherline CNC - Setting Backlash in Mach 3

The machinists obsession with backlash is understandable and I have a healthy respect for having it set correctly on Mach 3.

I think 0 backlash is a little crazy, it can't realistically be done or is at least is not worth the effort, especially when it's not necessary. I also believe that my Sherline doesn't like low numeric backlash numbers at all, the Sherline wasn't made for it and would require expensive upgrades to do it right. It also doesn't like the ways too tight either.

 Two images take you through the Mach3 menus.
1st select Backlash from the Config drop down.

2nd: Enter in the numbers you get from your machine backlash analysis

Say OK and that's it.  I have set the Backlash speed to 25% after becoming very leery of running my machine anywhere near top speed. 

To get my backlash numbers I use the following method.


I set up a 0.200" travel indicator especially for quick and easy use.and developed the universal bracket that can be turned 90deg. or positioned anyway that works best.

Small detail; because the indicator is offset from the spindle it rotates and so the spindle must be held fixed. I made the little snubber you can see on the top that I can jam against the pulley to keep the indicator from moving.

Instead of the short travel indicators the long travel makes all the difference; I drive it at least 0.500" into a right angle plate and use the 0.100" jog mode on Mach 3 to go back & forth. I do it all real time; check the reading on the indicator, change the setting in Mach 3, hit enter and check the indicator again. 

Doing this once a year is not enough, I'm trying to do it at the start of every new project and I'm keeping a log too.