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April Through June 2006 CNC Blog Archive

6/26/06

Make a Dodecahedron on Your Lathe

In the realm of, "But why?", I offer this fascinating fixture to be used for making dodecahedrons on a lathe:

The basic fixture...

Start with a turned version. I could see designing the fixture to work with a 4-jaw chuck as well, maybe better as it would clamp better and have no need of the socket head screw on top to hold.

Now face to cut each facet...

Isn't that cool? Another similar thing would be the Turner's Cube that relies on boring successively smaller holes in a cube:

Adapting a 4-jaw to hold the Turner's Cube...

A finished Turner's Cube: Absolutely Mesmorizing, Ain't It?

Digitizing a Quarter

Have you ever wondered about those digitizing probes you can put on a CNC machine? I came across an article on using one to scan a quarter that provides a great introduction to them. This particular article is by the DeskCNC people who are using their software together with an IMServices scanning probe. Basically, the hot glued a quarter to a metal plate and went at it:

Quarter hot glued to plate and scanning probe approacing...

The process involved scanning an area slightly under 1" square and required 3.5 hours to produce a 3D model involving 95,000 points scanned. The result is pretty impressively detailed:

The scanned 3D model...

Check out these IMServices guys. Their prices seem very reasonable, especially given the quality of the results and what looks like a very slick piece of software to automate the probing. I suppose you could also haunt eBay looking for Rennishaw probes, but you'd have to figure out to interface one if you got it. I doubt you'll find one much cheaper than IMServices offer, and the condition will likely be undertermined given it's eBay.

6/25/06

PC Chassis for CNC Lathe Conversion

Did a little mill work on my pc chassis for the lathe. I'm building a little Micro ATX Athlon system, which is way overkill for this application, but for a new mobo and cpu, it was still pretty cheap. I'm planning to try to focus on this chassis and get the little pc up and running first so I can install software and so on. I'm converting a rack unit I got off eBay to house the pc, and I will use a second identical rack unit to house the GRex, Geckos, DC power supply, relays, and so forth. I used the IH mill to make some cutouts on the back of the chassis. I made one for the power supply and one all the cables will go through. We only really need 4 cables--Keyboard, Mouse, Video, and LAN, but I made it big enough for any concievable connections. I am planning to use a sort of rubber flap over it to keep the chips out. I think this is better than individually bezelling all the connectors out the back because I think the typical PC connectors are chip vulnerable. I will also try to "harden" the power supply against chips by putting a filter on the back of it. We'll see whether this chassis calls for a cooling fan, but if so, I will use a filter for it too.

It sure was fun making those cutouts on the back with the mill. I was cutting thin aluminum with a small 4 flute mill at maximum spindle speed. It just cut through like butter and left a very nice surface finish. Of course, before I could do all of this I had to line up my Kurt 6" vise on the table and install a new set of jaws in it. Seems like there is always something slowing you down, eh? Well that big 6" vise is sure heavy compared to the Kurt 4" I normally leave on the table. It did the job though.

Phase II Rotary Table Tips

Here is another important tip. I got a Phase II 8" rotary table just a little while ago from Kap Pullen. He is a regular contributor to the various boards I read and a heck of a nice guy with some great prices. Anyway, I found out after I got it that the darned thing doesn't use the same 5/8" T-slots as my mill. It looks just under 1/2". Kap says the spec sheet calls for 0.465". So, I had to go looking for a 1/2" clamping set to order. If you're buying a rotab, be sure to check into what sort of clamp set you need or you'll be wondering how to put it to use after you get it!

Another tip for that table. I had some 2" Kant-Twist clamps, and it seems they engage the T-slots perfectly. This was a convenient way to clamp my PC chassis to the rotab so I could mill some fan holes.

Holy Spinning Tombstones, Batman!

Saw this intriguing idea in a thread over on CNCZone today:

4th Axis Tombstone...

The idea is to be able to mount parts on at least 2 and preferably 4 sides of the spinning tombstone and then let the mill go to work on them, flipping to a new side whenever it finishes the parts on one side. Hard to see how this is faster than just loading sub-plates onto the main fixture plate unless you need to leave the machine unattended for quite a while. Anyway, I do enjoy learning tips for how the pros would go about manufacturing something using CNC tools.

Miscellaneous Milling Activity

Okay, there is a lot going on in this picture of interest:

A right angle mill head with arbor and saw saves a facing + parting off lathe step in manufacturing Delrin ACME nuts. Note the stop on the mill so he can just keep feeding them in as each one is cut. This is some more Widgitmaster workmanship.

Here is what he is trying to make. A CNC lathe with a powered drill on the cross slide would make short work of this job too! See my notes below on adding an encoder to the DC spindle motor of my lathe to make it a servo and allow precise indexing.

SPI Table Stops

SPI makes these little mill table stops with a 5/8" T-Nut on the bottom. It can be extended up and down, left or right. Also very nifty!

6/24/06

Big Brass Knobs for My Mill

Wait, what did you think I meant! Last night I made a "couple of big brass ones" for my milling machine gib locks:

My new milling machine gib lock...

Designing an Optical Limit Switch

I also did some thinking and drew up a design for a limit switch based on some slotted optical switches I bought a while back on eBay:

An optical limit switch...

Augment Google with Clusty

I found an interesting new search engine called "Clusty" that I really like. It isn't a replacement for Google by any means, but it is handy for certain things. I went ahead and added it to my personal home page. Try it, you'll like it!

6/17/06

Tramming Jack

I came across this interesting concept recently, a "tramming jack":

Tramming Jack...

Let me try to explain what's going on here. This fellow is using the little machinist's jack together with the big square frame he welded up to make fine adjustments to the tram of his mill head. The jack gives him a fine adjustment screw for the task. I thought this was an interesting alternative to hammer thumping while the locking screws are half tightened, which is how I learned to do it. Perhaps one could fabricate a more elegant approach using a fine screw secured to the head and the mill table. Imagine a sort of turnbuckle arrangement. OTOH, maybe it would just be very inconvenient compared to the hammer. I'll have to give it some thought.

6/14/06

A Chip Compactor for the Shop

There is an interesting discussion over on the CNCZone about building a chip compactor with a 30 ton hydraulic ram to make recycling chips easier. The idea is to compress them into "pucks" so they take less space and so the coolant can be forced out for recycling. I drew up a quick Rhino rendering to try to visualize what they were talking about:

A chip compactor...

In the drawing above, red is the compression chamber, ram enters from above. Purple is a gate at the bottom that opens so the puck can drop through. The series of holes in the green base plate allows coolant to run out a separate path for recycling.

Dovetail Cutter for Making QCTP Holders

I got busy last night making a dovetail cutter so I can make AXA QCTP holders on my newly installed mill. Did the lathe work. Milling the pocket for the carbide insert is the next step.

Someday, son, you can be a dovetail cutter too if you work hard for it...

6/10/06

Asian CNC Mini-Lathe

Here comes a mini-lathe from China with CNC:

Nice travelling chip guard and ball screw covers!

Heat Treating Oven

I have been interested in heat treating metals for a long time, and finally sat down to do a little web research on how to build a heat treat furnace. Industrial PID controllers are readily available on eBay cheap, and the rest of the materials required are not expensive either. If you wanted to buy a heat treating oven, you should look at units made by Paragon Kilns. The knife making community seems to swear by these units. Depending on the model you choose, they run from $1200-ish to as much as $4000:

A Paragon Heat Treating Oven...

I'll probably try to build one for fun, so I'm adding something like this to my "someday" project wish list:

Home-built Heat Treat Oven...

In fact, I've added quite a few things to that wish list page recently.

6/5/06

Interesting Shop Made Tools

Some interesting amateur-built tooling:

Tubing bender...

Graver sharpening jig, also called a "Barlow's Wheel"...

Ball Turning Attachment for Lathe...

Finished the Mill Stand!

Yes, I am definitely slow, but sometimes steady progress is all we've got. Finished welding and painting my mill stand over the weekend and this evening:

Mill Stand painted Industrial Hobbies Blue...

6/4/06

Apply Your Own Ceramic Coatings to Headers

I'm always interested in industrial finishes for parts, not sure why, I just am. I came across this interesting article on applying ceramic coatings to engine headers: http://www.customclassictrucks.com/techarticles/137_0312_cerm/. It turns out there are quite a few different functional coatings like this that can be applied in the home shop, including Dry Film Lubricants, Thermal Barrier coatings, Thermal Dispersants, and Corrosion- and Chemical-Resistance coatings. In this case, the ceramic coating on these headers is applied with nothing more than an automotive touch-up spray gun. Mind you, spraying the coating is the easy part. To make it work you will need to be able to bake at up to 600 degrees.

Garage CNC Business

Aside from finishes, I'm also interested whenever I come across a small CNC business:

    White Wolf Airsmithing is one such business. This guy is making very cool custom paintball gun parts using a Taig mill.

 

5/30/06

Mill Vise Caddy

First, a nifty accessory for moving your vise on and off your mill table:

It's so nicely made, isn't it? You clamp the vice jaws onto the thing and you can lift the vise off and swing it out of the way. It almost seems to me like something slightly more general would let you keep a bunch of vises, rotary tables, and other goodies on a shelf behind the mill and bring them on and off as needed. You can by one already made from SPI (via MSC or other dealer) which calls the product a "Mill Vise Caddy." Cost, $339. I'd say it's well worth making one, and have added it to my project list.

Shop Made CNC Hydraulic Tubing Bender

Second, may I present one of the most impressive projects I've yet seen? This fellow chip has made an NC-controlled hydraulic tubing bender from scratch. He's a MechE student at Cal Poly, and it is just the coolest project ever.

Wow! NC-controlled Tubing Bender...

I wish I could say I was adding this one to my project list, but truthfully, it looks too ambitious for me at the moment. Maybe someday when I have more time and experience I will revisit. Meanwhile, I just enjoy reading the thread he's written.

Mirror Fixtures for Small Production Runs

Onward to some less ambitious, but still interesting findings. Here is a clever idea for small production runs:

Flip fixture is at top, half machined parts in middle, finished parts at bottom...

The idea is a special fixture to make it easier to machine the back side of a bunch of parts. The parts are laid out 6 to a piece of metal. First you mill out the top half. Then you flip the piece over, dropping it into the "flip" fixture on the vice. It is a precise negative image of the parts, which holds them in place, and allows you to machine the backside of said parts. When done, you dump the finished parts out of the flip fixture and go again. Neat, eh?

Mill Tramming Bar

Okay, here is another super simple idea that would be an easy project. It's a tramming bar for a mill:

Tramming Bar...

Dead simple to make, and easy to use too. Just need to make sure the shaft fits a common collet size.

5/22/06

Awesome Shop Made 5C Collet Chuck

From the category of Amazing Stuff, I present this 5C collet chuck that a fellow from Practical Machinist named "j king" made. It uses a planetary gearset from a transmission to gear down the handwheel in a compact way and tighten the thread on the collet. The handwheel is nicer than the keyed 5C chuck I've got (and which I still need to make a backplate for!). Other detail notes: there is an O-ring to keep the handwheel from rattling, and there is a sleeve pressed into the small gear. Since the transmission gears are hardened, the sleeve was necessary to allow threading for the 5C collet. It is brazed into place. The workmanship and sheer beauty of it is amazing:

The component parts. Note there is a gear barely visible in the righthand part, and the little gear in the middle is threaded for the 5C collet...

Here is a better view of the gear mounted in the chuck...

The D1-3 backplate, also a beauty...

Handwheel looks CNC'd, but was done manually...

Threaded for the 5C collet...

Thrust bearing inside to keep from over tightening...

Here it is assembled and ready for use...

Looks like he's using that thing on a Monarch 10EE lathe, another really nice piece of work!

Servo for Lathe Spindle

In the category of "Food for Thought", I am considering what it would take to get servo drive of my lathe spindle. There are two approaches I can see. First is to buy a 1KW (roughly 1HP) or more servo and use it directly. Second would be to add an encoder to the existing DC motor, thereby converting it to a servo. The link I give for converting a motor looks promising to me. However, the gang on CNCZone had a fairly dim view of it initially. The feeling was that it wouldn't do well holding still because of cogging effects on the motor. One fellow did opine that he was experimenting with a similar rig to good result. I think in the end of the day I'll just have to try an experiment. Now why, you ask, would I want to do this? If I can reliably index the spindle, in other words get it to stop at a precise orientation, I can use it as an additional CNC axis to good effect. Imagine mounting a drill to the QCTP. With precise control of where the spindle stops together with the cross slide, I can now position the drill to any point on a faced surface. The final axis allows me to drill a hole. With this kind of capability, I could turn out NEMA 23 step motor adapters that are cylindrical in one setup, simply by changing to the drill fixture as the last step to drill the 4 motor mount holes. Likewise, drilling holes perpendicular to a shaft would be easy as well. A 3-in-1 machine would be particularly powerful because an indexable spindle instantly creates a 4-axis milling machine. In any event, encoders are pretty cheap. When I get the lathe converted to CNC, perhaps I'll buy a Gecko servo drive and an encoder to experiment with. I have a spare identical DC motor to the one on the lathe. It might prove a very worthwhile line of inquiry!

Cooling Box for Air Hardening Steel

Okay, my last note is a quickie. I came across this nifty cooling box for air hardening steel:

Cooling Box for Air Hardening Steel...

It's just a simple rack with a box fan sitting on top of it directing air down through a grate. This would be great if you were doing some kind of small manufacturing run of parts made of air hardened steel. It's useless for annealing, as you need to cool very slowly in that case--the cooling rate is very critical. The book says 40°F/h from 1600-1650. That's 20-24 hours at a steady rate to still be 200°F. The non-magnetic point being 1425°F appears to be too low to anneal. H-13 is one air hardening steel. To heat treat, heat it until it is non-magnetic. Wrapping the part in foil is preferred if you have a forge or furnace in which to do the heating. Cool it down in air. Reheat to 1100 degrees F to temper, which should leave it a nice plum color. D2 and D7 are two other air hardening steels.

5/17/06

More CNC Lathe Progress: Control Panel Cabling

I got busy and figured out a couple of issues that had been plaguing me on the cnc lathe project. First, I determined that I can use a parallel cable to connect the control panel to the drive electronics enclosure. That was a relief as I was worried there would be too many connections and I would have to resort to some kludge involving multiple cables. I will use a couple of screw terminal breakout boards to make the point to point wiring at either end simple too:

Parallel Breakout Card...

At $20 apiece, they aren't dirt cheap, but they aren't bad either and they radically simplify the effort at my end.

The GRex is in the House!

The second big event that happened today is I got my GRex. What a sexy beast it is! It's so small, looks so well made, and has so much potential locked up inside of it. I've got to get busy so I can put this thing to good use.

Lathe Coolant and Spindle Control Wiring

Lastly, I spent time working out most of the details for how to wire up the coolant and spindle controls.

5/16/06

Make Your Own Flex Couplers

This just in: you can make your own flex couplers:

I'm not saying its cost effective,this one can be bought for $10, but I like the idea of designs that incorporate a flex coupler into some other part. Check the rotary table conversion down below to see what I mean. The style pictured above looks straightforward to cut with my DeWalt Multicutter carbide saw. Or you could use a slitting saw. Probably want some sort of hardened steel to make sure it is springy. I like this idea because I think you can simplify your design by incorporating the flex coupler into another part rather than having to come up with an independent coupler. This approach can also result in a more compact design.

5/14/06

Fabricating the PC Enclosure for the CNC Lathe

Got some actual work on the lathe done. I have started fabricating the enclosure for the PC that will drive this thing. I plasma cut the front panel for a DVD and power switch, and drilled the mobo tray and installed some nylon stand offs for it. Every little bit of progress helps!

I also ran over to the steel dealer and bought some 4x4 steel tubing, some 4x2, and some 1/4" plate. This is what I'll build my mill table out of. Got to get going on that project too!

Electrolytic Weld Cleaning

Ran across another interesting gadget--there are so many in the machining world! This one is an electrolytic weld cleaner. The idea is to remove discoloration from steel caused by welding heat using electrolytic action. Apparently they are nothing more than a 40V DC supply applied to the work using a sponge that's been dipped in some form of acid, usually phosphoric. Commercial units are very expensive, about $800 - $1000:

    http://www.screenpro.net/weld.htm

Sure seems to me like a stepper-motor DC supply would be cheap to build (<$100) and perfect to produce a homemade weld cleaner with. Apparently these commercial units rely on fiberglass tape, held on with electrical tape, to act as their sponge. I'm envisioning a wand with the fiberglass tape on positive (have to check that !) and a welding-style ground clamp. Supposedly the ScreenPro wand was made from a piece of flattened copper pipe (high tech, eh?). I've got too many projects right now to mess with this, but will keep it in mind for later.

QCTP Holder Rack

Here's another project I've got to build some day soon. What a clever way to save space and organize your QCTP tooling for the lathe:

Notes on Tapping Heads

I got interested in tapping heads, and so made a few notes based on my web research:

I'll keep an eye out on eBay for a deal on a tapping head so I can try one some time.

What Is A Left-Handed Veeblefetzer?

I bought a left-handed Veeblefetzer:

Left-handed Veeblefetzer...

What the heck is a Veeblefetzer, you ask? I dunno, but it looks to me like an ideal component to use in making a shaper attachment for my lathe. I've been wanting a shaper attachment ever since going through the painful process of trying to use the rack to move the cross slide back and forth manually as a shaper. I actually don't really object to the manual aspect so much, but a real shaper attachment would make the process so much quicker and easier. Add it to my list of projects I'll get to "someday".

5/6/06

Flood Coolant Musings and Tips

Been running across some interesting new ways of looking at things lately. For example, I was sniffing around this morning trying to learn more about flood cooling. It seems clear everyone feels it's the best way to go, especially with CNC, but at the same time it is difficult to set it up and potentially messy. I have to build a drip pan and enclosure for my mill, make sure step motors are protected if I CNC, yada, yada. My understanding was that it mostly lets you cut faster and the cutters will last longer (one fellow said it tripled his cutter life and doubled the cutting speeds). In addition, it's useful for clearing the chips on CNC since you don't want to get in there with a chip brush while the cutting head is flying around unpredictably at 100 inches per minute! What I read today is that they also improve accuracy. The reason is obvious if you think about it, if the workpiece or tool changes temperature too much the thermal expansion is going to affect the cut. Here again, I think this is probably more important for CNC because your initial touch off is going to set your accuracy whereas a manual machinist is probably going to check the cut a few times along the way. At least I do! Another fella mentions that all the wet down from flood cooling keeps the chips from travelling so far, which makes them easier to manage and clean up. Along the way, I picked up some other handy tips too:

4/30/06

I've been remiss in my blogging, so I have a lot of catching up to do here. Bear with me, as this may be a long passage today.

Thing of Beauty: Tree 325 Milling Machine

In the Department of Someday I Want One, I firmly place the Tree 325 milling machine. Many fine authorities swear this machine is way better than the average Bridgeport in terms of precision or rigidity, and you can tell with one look that there's plenty of beef there to back that up:

A Tree 325: Someday I Want One!

These Tree mills appear to sell for somewhere in the $4000 to $10,000 range depending on what condition they are in. A sweet deal would be to find one that's mechanically sound but with a blown controller. Switch that bad boy over to a PC-based control running Mach and you would be in bidness!

High Speed Machining With An Air Spindle

High Speed Machining: This is a big buzzword these days. It focuses on higher spindle speeds. To after aluminum you need well over 10K. Most spindles in machines I can get my hands on won't touch that. How about a nice retrofit air spindle that is removable? Check it out:

30,000 rpm air spindle

Just the ticket for super high speeds for engraving or 3D profiling in aluminum. This one is made by MacroTechnologies. They have another model that mounts to the spindle directly rather than being in a toolholder like this. Slick!

Laser Measurement and Metrology

I became really intrigued with the precision of lasers and their application to metalworking after reading a link about using a simple laser level to measure flatness of a surface with an accuracy of 0.0001"! This led me to create a page to capture the technique. By the way, there is a whole home page for layout and measurement, if you weren't aware. Check the laser metrology page for more details on this fertile area. I did some research, but it is far from complete.

Rail Mounting Precision for CNC Plasma and Router Tables

The reason for the laser measurement thoughts mentioned above is my planning for a CNC plasma/router table. This table will be built using linear slides. You have to mount the slides on a flat surface as they are not strong enough to avoid flexing if mounted to something not so flat. In fact, they are typically designed to be mounted on a surface that has been milled or ground flat both under the rail, and along a ridge that one side of the rail butts up to. There are a number of threads and thoughts on how to go about creating such a flat surface of sufficient size for one of these large machines. One such advocates using a grinder and precision level and claims an accuracy of 0.001" in a day's work. Another uses a moglice-style approach wherein metal impregnated expoxy is used to create a flat surface on which to mount linear rails. The resultant Madvac Kayak Router is a very impressive piece of work. Here is the CNCZone thread on the Madvac as well, FWIW. There is a lengthy thread on CNCZone that covers this approach in good detail as well, though it was for a work-in-progress as I write this. Lastly, Bosch Rexroth has an article that provides a pretty detailed introduction to how to mount linear slides, but the link keeps moving, so I have given up offering it.

Linear slides want a flat surface and an "edge" to keep them properly aligned...

After studying all of this material, I have so far concluded that my Y and Z axes pose little problem. I have purchased a commercial Z-axis from eBay that I believe will serve very well. I have a piece of 3/4" thick aluminum that I will machine for the gantry cross piece. I would expect it to be rigid and relatively light. I intend to use my Industrial Hobbies mill to create the kind of rail mounting surface (i.e. with a flat bottom and an "edge" along one side of the rail) used on commercial machines. That just leaves my X-Axis which is more challenging. The current plan is to build it out of a framework of 4" square tubing with 1/4" walls. In this case I'm wondering if a couple of suitable pieces of thick aluminum can be machined and then bolted to the surface of the square tubing with suitable shims to avoid stressing it too much. The rail would then bolt to that piece. More thought is needed!

Build a Fighter Jet With Your CNC Router

Along the way studying these various intricate threads, there are always side trips and distractions. If you've ever wondered what someone might do with a fancy CNC router, how about building molds to create radio controlled jet aircraft:

Molds created by a CNC router for a radio-controlled fighter jet. Cool, eh?

The Ultimate Yo Yo

While cruising Practical Machinist I came across one of the coolest "fun" CNC projects I had seen in a long time. This fellow's goal is to manufacture the ultimate YoYo:

The CNC'd YoYo...

Of course I had to do a quick Rhino drawing of it just for fun myself:

 

4/12/06

Acoustic Chatter Recognition

This is an intriguing technology that measures the natural resonant frequency of your machine and workpiece in order to predict the optimal spindle speed to run at with minimum chatter. Ingersoll makes a product called "Harmonizer" that is dead simple. It's a microphone connected to a laptop computer that then runs some Windows software. The software basically produces a graph showing you the stable zones of spindle speed where chatter should be minimized. Very cool! Now imagine Mach V (I know, it doesn't exist and isn't being talked about). It drives the motors using a GRex, so there is plenty of PC bandwidth available. There's a new function that let's you turn on "Acoustic Chatter Suppression". This feature requires a microphone input to the PC so it can listen for the chatter frequency. It will then automatically select the optimal spindle speed to minimize chatter. Now that would be an amazing development!

Adjustable Welding Table

A really nice welding table with adjustable work height:

Fully extended--note the hydraulic struts to hold the weight of that massive table...

Retracted for seated welding...

Machinery Lifting and Moving Dollies

How about this fellow's machinery lifting dollies:

4/11/06

Veritas Optical Center Punch

Here's an interesting new tool I came across:

Veritas Optical Center Punch ($31.50)

It's a nifty little tool that let's you precisely align your center punch on the correct spot before giving it a tap with your hammer. I like it, but I wonder at it's usefulness in the wake of CNC? More and more the thought comes to me that many tools are suddenly no longer necessary if you are doing everything with a CNC. When I actually get all of my machines converted, I'll have to delve back into the subject and see how true it relaly is.

4/9/06

Cross Slide Drive for CNC Lathe Conversion & Circle Machine Boring Bar

A bit more progress made over the weekend. I remade the shaft adapter for the cross slide axis over the weekend. It wasn't a hard project. It's purpose is to screw down onto the end of the current shaft and provide a convenient smaller shaft for the helical beam coupler to grab onto. There were a couple of annoying bits. First, as I mentioned in my 4/2 post, I had managed to break a boring bar and chip a drill bit trying to increase the bore on the coupler. They're made of a hardened spring steel and are quite tough. The solution was a Circle Machine boring bar I got off eBay. These are beautiful little tools:

Circle Machine Boring Bar via eBay: Sweet!

New, they can be quite expensive, but they are sometimes available on eBay. I got lucky! The best news is that there was absolutely no trouble using this bar to cut into the coupler at all. It went very smoothly and without a hiccup. There is something to be said for high quality tools when faced with difficult situations. It was like an entirely different lathe, and I'm sure had I not broken the bar I would've blamed any problems with chatter on lathe rigidity. Note that this isn't even the solid carbide bar, which is even more rigid! But I digress.

I got the new coupler-adapter made pretty quickly. I wanted to improve it in several ways. The first one I made required spacers, so I made this one longer. I also wanted a little thicker shaft into the coupler for strength. Lastly, I needed to cut a keyway so that the motorized back and forth wouldn't work the screw loose that holds the coupler-adapter in place. This last, making a keyway, was painful! I basically used an HSS-Cobalt tool I had ground in the lathe's QCTP and racked back and forth simulating a mini-shaper. It was a painful and imprecise operation at best. The last little bit had to be cut using the HSS tool and a ball peen hammer chisel style. I can definitely see why folks like having a shaper around. This was a blind hole and would've been painful with an arbor press and broach set. It also opened my eyes to the thought that a shaper specially intended for cutting keyways and of much smaller capacity would not be a bad thing. Of course I'm not the only one with this idea!

An Air Operated Shaper Attachment for the Lathe

Pneumatic Shaper Attachment...

That's a design for a pneumatic shaper attachment to be attached to a lathe. It uses an oil dampener, and as you can see there are a number of adjustments. I really hope Evan decides to build it and will be watching the thread closely for updates!

My next step on the lathe front is pretty simple. I need to track down an M6 allen head bolt to go into the cross-slide shaft and trim it to an appropriate length. After that, I will trial fit things together, and hopefully will be able to consider the cross-slide done. If that is the case, it will be time to get focused on the electronic bits. I'm thinking I'll do the PC chassis first as I have all of the pieces on hand to finish it up. That also lets me procrastinate a little while longer over whether it makes sense to use the GRex or go with the Hohman ModIO and get 'er done.

Converting a Rotary Table to a 4th Axis for CNC

Here's a nice project I saw written up recently. It's a stepper conversion for a rotary table so you can add a 4th axis to your CNC mill. This fellow is manufacturing these things and is an amazing machinist. Check it out:

Rotary Table Stepper Conversion

There are a couple of features to the design I really like. Firstly, note how the shaft adapter is actually a machined part of the Oldham-style coupler. Why hook a coupler up twice? Much better design than what I'm doing on my lathe. I'll have to convert once I get my mill going and can machine that tab. The second is the stepper mounting bracket. The tophat-shaped cylinder has a flange on it. The square flange has a milled recess that catches on the round part's flange. Now, when we bolt on the stepper, it is basically a matter of sandwiching the cylinder's flange between the stepper and the square flange. This let's the motor be rotated to any orientation and is a very simple piece to manufacture.

4/6/06

eBay Linear Slides

I received a pair of HSR25 linear slides today from an eBay win. What beasts these things are! They are big solid rails and heavy trucks, 2 trucks to a rail. I bought them to use in creating a plasma/router table. They're not quite 50 inches long. Looking at them, I almost hate to "waste" them on such a project. They'd make a fine mill or lathe axis. OTOH, they didn't cost me very much.

ESAB Plasma Cutter

BTW, speaking of plasma tables, I got my big ESAB plasma cutter running this last weekend:

My brother cuts with hot plasma...

That ESAB Powercut 1500 cuts likes dream! So does the De Walt Multicutter cold saw sitting in the background. Anyway, the thing we both noticed is that this cutter has so much power, you can hardly move it along fast enough manually. Hence the need for a plasma table. The other idea that struck (where am I going to put a plasma table?), was to build a welding shop on top of the car lift you see in the picture. It's the only way I've got room for it at present, and I am not using the lift much for cars.

Put a Welding Shop on a Car Lift

The idea would lay out something like this:

As you can see, there would be room for a decent sized 1/2" plate welding table, the 2 welders and plasma cutter, a smallish plasma table (4 feet x 4 feet), and a spot to put the DeWalt saw with room to saw pretty long stock. When not in use, push a button and the hole thing goes up into the ceiling and out of the way. I can park a car under it with ease. The idea has potential!

4/2/06

Broken Boring Bar

Was continuing to refine my cross slide CNC adapter and managed to break a boring bar. I was trying to enlarge the hole in a helical beam coupler. The operation had worked fine on the leadscrew side but did not go well on the cross slide. I chipped a drill bit and then snapped the head right off my boring bar. Doh! A new bar is on order, but I can't get much further without it.

Lost Wax Casting Steam Engine Parts

I was purusing a new discussion board and came across an interesting article on lost wax casting for a scale steam engine project. Wow! This guys parts really come out looking nice. He's using a CNC to machine acrylic which is then used as a wax mold for the casting process. Here are some photos:

The acrylic mold for the wax...

Wax injector injects molten wax into the mold under pressure...

Vacuum chamber and flasks for lost wax casting...

Finished stack for a Shay steam locomotive...

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