Leadscrew/Ways Cover

A cover for the Sherline mill it’s a must if you wish your mill last. This is the typical “accordion” cover, a very practical solution actually:

Now here’s the leather/delrin cover I actually use. Tough not pretty, a good thing about it is that it allows easy access to X axis lock screw (something that I use a lot).

leather_cover-01leather_cover-02And here’s the new cover for my modified Sherline cnc mill:

sherline leadscrew covercnc_cover-02A bit radical but effective and easy to clean (I hope). I will comment the whole design once completed.

Now, the next things I need to tackle will be anti-backlash nuts and column mount.

Finishing my CNC controller

Ok, I know I said I would start this several months ago. But the fact is that I’m beginning just now… and the first task I need to accomplish is to finish my long-delayed cnc controller.

controller-01

I build this thing around three years ago. The chassis (11″x9″x3″) was a from an old optical reader; I love it, it’s very high quality (it’s nice to bring new life to scratch). The motor drive was the STK672-050, a Sanyo 3.0 Amp unipolar stepper drive. I did use 6 pin mic connectors, they are pretty cool. I got the 5 volt supply from a cell phone charger. Currently It’s a 3 axis controller, but there’s room for another axis if needed.

controller-02

Please note I’m aware that bipolar driving are the preferred choice for cnc equipment, but I’m confident this will do the work. Supposedly one advantage of unipolar over bipolar driving is better torque at higher speeds (look here). My choice was driven mainly by availability of this driver years ago. Now chinese TB6560AHQ red boards seems to be a better option (after reading this, I realize first generation boards where a pain in the ass); in fact, I plan to order one of these for backup and/or testing.

controller-03

This controller works very well (fast movement, not strange* noises, hard to burn), but I need to remake the pcbs due to a positional error, and after that, I need to mount the heatsinks and finish some details. So I need to start cutting some pcb board… guess have the perfect tool for this :D.

* No strange noises, but the typical noise when idle.

Woodworking

I have a high respect and admiration for woodworking, and tough I have the tools (chisels, saws, planners, etc), rarely find myself working with wood. More commonly I build particle board furniture, and tough it’s not easy, I wouln’t call it woodworking.

This is a toys shelves project for my son. I could made the sides of particle board, but I wanted something special and liked the idea of a painted wood frame.

Tough this is a simple half-lap joint structure, It required a lot of work and tools (as always, much more than I expected… this isn’t a weekend project). One thing that makes it harder it’s the fact wood bars aren’t exactly the same width. Also I almost never can cut perfectly square; always had to use the chisel and/or file to correct the cut.

I did all with manual tools except rounding the edges; for that I did use a router. Also I did the all holes with my small microlux drill press.

woorworking_05

Not bad. It’s nice to see how practical considerations and a little of devotion cand lead to a beautiful design, without pretending doing something beautiful in the first place (I sometimes envy designers capabilities to create cool designs). May be it’s has to do with the way nature works.

Micro table saw

This long desired project is finally finished. Now I can clean-cut metal, plastics or wood stock easily and with minimal loss. I think everyone working on small parts must have one.

The idea

Some time ago I was working on my cnc lathe and get tired of my options to cut stock, so I decided I needed a mini table saw before continue. Proxxon micro table saw seemed to be exactly what I needed, but I choose to make my own.

My start point was a 1/4″ 51x17cm aluminum plate, a 1/15 hp ac/dc 5000 rpm Dayton motor, three proxxon saws, and, of course, the Proxxon micro saw as a reference design. I got three of these motors for $16.00 plus shipping on ebay (well, I order two, but, the seller forgot to ship them at time and kindly add a third). Please don’t ask for motor a source; the original seller isn’t available anymore.

Building

I began designing key elements: the table itself, the motor mount and the saw rotating support. Once I build these parts and put them together I got a functional saw, that help me to build the rest of the parts.

One of the tricky steps was to cut the aluminum rectangle to size and square it. As the length was larger than sherline table travel, a two step mill and hand filing was required.

Fence was made of delrin and aluminum, and has two locking screws. Assembly allow some degree of adjusting so delrin guides slides without play over aluminum.

Angle guide was made of delrin and a 1.5×12 mm brass bar. Tough at first I thought that was really unnecessary, it’s a must to cut bars.

Timing pulleys and belt are 3mm pitch / 9mm wide HTD, and were ordered at sdp-si.com, an awesome site. Here’s the order:

Part Number                  Quantity    Unit Price    Extension
————————————————————————
A 6R23M040090                1        $6.13/Each    $6.13
A 6Z23-017DF0908            2        $5.19/Each    $10.38

A dust receptacle it’s a must, as without it you get a mess of chips lying around. I build this using 3mm policarbonate (Lexan) sheet and 1.6m screws.

Table support was made using hard some wood I salvaged from an old stepladder.

Tough you can make thumb screws on the lathe, I choose to buy them on ebay. I got a bunch of 30 (three types) for $5,74 plus shipping from a Uk seller. They are nice.

Testing

I got three proxon saws: for wood, hss for metal and carbide tipped. The first only works for soft wood; for hard woods carbide tipped must be used. The hss one works great for thin metal sheets, but clogs on thick plates. With the carbide tip saw I can cut 9.5mm (3/8″) of aluminum, tough not really fast (the saw clogs a bit). In this test I cut 6.5mm (1/4″) without problems:

Tough a little more of power would be welcomed, the motor seems to do the work. Something not clear to me is that Proxxon states this cutting capacities for their saw:

   Wood                                        5/16″ (8mm)
   Plastic & Circuit Boards     1/8″ (3mm)
   Non-Ferrous Metals           1/16″ (1.5mm)

tough it uses a 1/10 hp motor while mine is only 1/15 hp, and I can cut 6.5mm aluminum (more than four times proxxon capacity). Maybe it has to do with lack in rigidity or something else.

Overall

There was a lot of work in designing and building this tool, but was worth, and now is one of the main  tools in my shop. And it seems to have better cutting capacities (an precision, I guess) than the Proxxon one.

Draft drawings are available if someone is interested.

Update

Here are the drawings for the main parts. Please note that these are not detailed building instructions.; no tolerances, no part lists,  etc.

Some things to note:

  • I use R4 bearings: 1/4×5/8x.196 (metric 6.35×15.875×4.98). Bearings, bearing housings and spindle must fit without or very little play. Thread-locking fluid may be used in bearing housings if any play.
  • Spindle axis length should be some less than nominal (40*) to reduce axial play (this was a trial-error to me).
  • Pulley set screws must use thread-locking fluid. Without this, screws may get loose (this happened to me, not a nice experience).
  • The motor mounting block was designed to fit a specific motor.
  • I think the angle guide system can be enhaced by cutting a guide with a T profile (4th pic, below). A dovetailed guide would be even better.
  • A thicker table (let’s say, 3/8) would be another enhacement.

CAD drawings HERE.