Boring stuff

Currently I’m doing some modifications to my Sherline lathes in order to add a cover, very similar to the one on my cnc mill. This will result in a really big changes in the lathe look. I don’t feel comfortable doing these brutal changes to these beautiful machines, but it’s something I need to do.

cncworkOf course there are always some things that go wrong. If I were a professional machinist working on big machines I will be dead for sure. So be careful when you start cutting on a corner using traditional milling (not climb milling; I’m not saying climb milling is more secure, btw).

cncerrorI’m doing a lot of work with my cnc mill. I’m working on and with a really useful set of gcode routines that I will like share at some point.

Finally, here’s one of the more simpler yet useful accessories you can make for your Sherline mill/lathe, the “no hammer” (not my idea of course).

nut-01 nut-02 nut-03 nut-04

Can’t believe didn’t did this before.

Aluminum Sheet Cutting

My actual cutting parameters for aluminum sheet:

  • Material: 1100 aluminum (I’ve cut 1mm and 2.5mm sheets)
  • Feed: 600mm-min or 24IPM (I’ve used 800mm-min, but now I’m being conservative)
  • End-mill: 4-flute 1.5mm carbide. I’ve used 2-flute and 3-flute; the more flutes, the more quiet the cut.
  • DOC: 0.2mm
  • Spindle speed: max (2800 rpm)
  • Lubricant: some WD40
  • Finish pass required.


A lot of peoples says 1100 is a nightmare to machine, but as always, you just need to know it. I settle in these parameters by a test-error process, but I don’t now if these are the optimal ones. I just know these values work for me. And of course these small carbide end-mill would enjoy more rpm.

For 5052 I’ve used the same parameters, but you need to lower the feed a bit; a friend broke some end-mills at 800mm-min because of my speed thirst (nevertheless that was fun).

One last thing… the part in the photos is 2.5mm thick, so it was strong enough to withstand all the cutting with just a few screws. If that were a 1mm sheet more screws would be required.

The Perfect Paper

I’ve been building a leadscrew cover for the Sherline’s I’m going to sell. I think this is a must on any cnc machine.

I like the classical accordion-like cover, originally designed by So far, the main obstacle has been to find an appropriate paper. But I guess here is: Fabriano Tiziano Paper. This is a acid-free, 40% cotton, 160 gsm drawing paper. Very high quality and strong paper.


Folding has a trick; you should use a ballpoint pen to trace each line, pushing hard (kind of emboss). Even if you do this, folding is difficult, though not impossible.

And the best thing… you have a lot of color options!. I like the black-red combination.

An Incredible Project

DARwIn-OP is a humanoid open source robot developed by some prestigious universities. It’s not just a toy, but an advanced research platform; commercial version cost USD $12,000.00.


Some time ago I found a guy in my city that is building this thing on their own and I was amazed; that involves some serious metalworking, electronic and programming skills. He had some trouble because the largest part has a size larger than the cutting area of his machine (a 5400 Sherline CNC mill), so I provide my machine to do the cut; that was a lot of fun. So here is his site:


I will start a small (indeed very small) business soon; I mean, begin to create and sell some things. As I’ve said before, I used to work as software developer, and tough it’s not as bad, machines, tools, electronics and creating things is what I love and from what I wish to live. A lot of people around me are a bit sceptical (and sure they have good reasons), but I really don’t care; failing doesn’t really worry me. What worries me is to see time going without doing all can be done to achieve what I want (I know it sounds a bit cliche).

So, I’ve been doing several things in this days: setting up a FreeBSD server, switching to Ubuntu and open source tools, and starting to prototype my first product.

desktopMy Server

A version control system can be very useful to store and keep the track of changes of your work (even if you work alone). I already had a dusty FreeBSD server (I really love FreeBSD) with subversion and other things, but I wish something fresh so I install the last version (10) and setup subversion, websvn, dokuwiki and some other things. These are really nice tools.

Ubuntu and the open source

I had never been a technology enthusiast. My notebook is old, I use my old phone just for calls and up to some week ago I use windows xp on my old PC. Linux never attract me as desktop platform; I had all I need on windows. But when you wish to do some serious work, linux it’s unbeatable. Forget about viruses. Download all you need, free, from a central repository. I can easily do a new install, with all the tools I need, then checkout all my work files from my svn server and a get a working environment in a breeze.

Just one small complaint: Ubuntu’s default desktop environment it’s not resource friendly. So if you have old equipment, it will not run very smooth. Nevetheless the solution it’s very easy: install lxde, a lightweight desktop manager. I love lxde so much now. Also, maybe I give a try to lubuntu in the future.

From Eagle to KiCad

I’m a Eagle fan. But free version is for non-commercial work and has a limited footprint.  So I had two alternatives:  pay a Eagle licence (about $575) or try an open source alternative. The first time I put my hands on KiCad, some time ago, I find it a little polished and not very easy to use tool. Sure, I was a Eagle user. But when you begin to use KiCad and get used to its own way of doing things, you begin to love it. Sure, it’s not bundled with so many components as eagle, but it’s really easy to create a new device/footprint (also there’s a lot of extra libraries out there). And, although the board doesn’t update automatically when you add a new device, updating associations and netlist it’s just plain simple. My only complain: all footprints are in one big list, there’s no filter. But I can live with this. Good bless KiCad developers.

My first product

My first product will be a simple accessory for the Sherline lathe; some small parts and a bit of electronics, nothing special. My main objective it’s to get selling experience. Once I get confidence I will start sell more elaborated things (like a micro table saw kit or something else).

Name and domain

Finding a good name for your business it’s not easy, and finding an available .com domain for a good name it’s almost impossible. It wasn’t easy, but finally I did make a choice that has an available domain; now I should choose a domain registerer and webhost.  It’s sad buying and reselling domains be a common business.


I’m still not sure if I will sell on eBay or in the .com site. Actually there are a lot of alternatives to eBay, but I think eBay is a good starting point. Also, if you wish to create your own online store, there’s a plenty of free software tools. Some things I hate to deal with are legal and accounting issues, so I will tackle them later.

I don’t like to call myself an “entrepreneur” or something like that; I just want to give the effort some things deserve.


My first cnc part

I should say the hardest step in making this part was to press the start button (I’m a chicken).

linuxcncfirst_cnc_cut_01b first_cnc_cut_02This 1mm sheet was held to a mdf plate using Carnauba; that seems to work nicely. Badly I made a mistake and the DOC was about 0.5mm (hence two runs where required), so I’m still not sure if 7 IMP is ok for 1mm DOC.

Things I learn:

  • Finish was ok in round cuts, but not so good in slots. Next time I will separate roughing and finishing, so I can clean the chips before finishing passes. This is when hand coding gcodes pays.
  • I need to buy Acetone to clean Carnauba.
  • Regarding outside diameter, I find a max of 50.08 and a min of 49.90. May be this has to do with backlash (I have backlash compensation enabled btw).
  • TODO: a tool height setter artifact.
  • My cheap Canon photo camera sucks taking videos.

The next task will be to cut the definitive encoder wheel for the machine spindle.

Preparing the first cnc cut

Up to this point I’ve worked in the lathe and the mill without worrying too much about speed and rpm calculation, trusting in my own experience and “feeling”, as a lot of hobbyists, I guess. Tooling wearing wasn’t ever an issue  to me; carbide tools seemed to last almost forever. Until I grasp Machinery’s Handbook and read “tool life for milling… should be approximately 45 minutes” (!!). So clearly in the cnc world choosing the right cutting parameters matters.

The cutting setup of my first cnc project involves:

  • 5052 Aluminum sheet, 1mm thick
  • 2mm, 3 flute uncoated carbide end mill
  • 1mm DOC
  • 2800 RPM
  • No coolant, just a some WD40

This LMS table states a speed of 165 FPM for 6061 aluminum (I guess it’s for HSS). So RPM = (165 x 4) / 0.0787 = 8386. Now, according to this, 0.002 IPT (inches per tooth) is suggested for 0.05 DOC, 1/8″ hss end mill over aluminum (closets size); 0.0015 IPT for my 2mm endmill seems reasonable. So using the max rpm’s (2800) gives me a feed of 2800x 0.0015 x 3 = 12.6 IPM or 320 mm/min.

Of course, due to the complex nature of this topic, suggested parameters for material/end-mill can vary a lot. American-Carbide suggest a feed of 16.000 rpm / 11.8 IPM for this cutting setup. And Whitney Tool states a cutting speed of 600 FPM for hss and 1200 FPM for carbide. As always Practical Machinist is a good source of knowledge.

Now some real world experience in the Sherline world.  This guy  broke his 2mm carbide endmill at 8 IMP, 0.5mm DOC. This other guy broke his 1/8″ 4 fl endmill  at 6000 RPM 14 IMP, 1.27mm DOC. In a test in my manual mill three turns per second (7 IPM)  doesn’t seem to break the tool.

So i think I will stick to 7 IPM for now and see what happens, and maybe later I get a set of teen end mills to do some testing and push further. Also, It’s clear I need to order the 10.000 RPM pulley set.