First the good stuff:

I decided to mount the power supply and electronics in a cheap storage container, which is exactly what I did with my last machine.  I used an x-acto knife instead of a drill this time, and did not any issues with the plastic cracking like I did last time.  However using the x-acto knife to drill this many holes by hand did lead to a couple of good sized blisters, there is a better way I am sure.  This part is pretty much done with the exception of a toggle switch on the power supply AC so I can turn it off without unplugging it.

Case 1

Case 2

Case 3

Case 4

Case 5

Now for the bad stuff:

After  hooking up the electronics I went back to my EMC2 settings and starting adjusting them to get the maximum speed out of each axis.  On the Z axis  (~8″ of travel) and X axis  (~24″ of travel) I was able to get about 42 IPM reliably, I backed the Z down to 12 IPM and dropped the X down to 36 IPM for good measure (As far as I can tell at the moment, EMC2 adjusts in .1 IPS, so I have to adjust in 6 inch increments).  On the Y axis (~48″ of travel)  I could get 36 IPM reliably, but had some issues when I got within 4″ if the motors (I need to figure out why, I am sure it is some sort of alignment problem), I backed Y down to 30 IPM.  BTW adjusting the Y was somewhat of a pain since every time the one of the motors seized, I had to realign both sides.  I did not have this issue with the first machine which also used dual screws, but my max speed was only 24IPM due motors and lead nuts, so I guess I never got fast enough see the issue.

I was really hoping to get speeds closer to 60IPM, some reasons I am not seeing this could be that my DIY lead nuts are too tight, there are alignment issues, or I just had unrealistic expectations, time will tell I guess.

I went ahead and ran the EMC2 default program a few times to see how things went, and had no issues.  Then I got stupid and decided to tape a sharpie to piece of wood and use some C clamps to attached it to the z-axis.  The first run went ok, but the pen was not secure, so the drawing was not that good.  So I added some more duct tape to hold the pen more securely, re-homed EMC2 and ran again…  the drawing looked better, but then I noticed that bottom of the Z axis was cracked,  it seems when I reattached the pen on a stick, I put once of the clamps a little lower and it ran into the bottom pipe clamp and cracked it.  I decided that rather than smash the machine, I would just go to bed.  (The drawing are also backwards, but this just means I need to reverse the X axis direction…I think)

Drawing Test

Cracked Part

The next morning, since I now had to re-cut the part anyway,  I resigned the way the pipe is attached to eliminate the splitting I had with the pipe clamping portion of the part.  I cut 2 copies of the part for the top and bottom of the Z axis, and I am now waiting for a little warmer weather to paint them and attached to the machine…  hopefully soon.

New Parts

Given that the part is now wider and contains a mix of saw dust and plastic, I am pretty sure I will not have the splitting issues.

Trex Parts

Another issue I had was that after drilling thru the lead screws and attaching my DIY couplings,  I was unhappy with the results.  All of them had some amount of wobble, which I found unacceptable, so I decided I might want to just buy some.  After doing some searching I came across this site: surplussales.com, which had some 1/4″ to 1/2″ solid brass couplings for $9 each, they looked adequate so I ordered a set of 4 ($41 shipped).  They arrived quickly, and I finally got around to hooking then up yesterday, much better.  I was so inspired, I went ahead and hooked up all the motors to the lead screws tonight, but resisted the urge to finish hooking up the electronics in favor of getting some sleep (my work will appreciate this I am sure).

Mounted motor

Ready to hook up to the electronics

I will probably get to the electronics tomorrow, defiantly by the weekend.  After that it is just a matter of cutting out the router mount… almost there.

Flex Test Starting Position

I then moved the gantry to the edge of the stack and attempted to remove the top most piece of wood…  it slid out without any binding at all.  While not very scientific, I think this demonstrates the minimal flexing issues I have observed up to this point, and bodes well for the future.

Flex Test Ending Position

I also replied to Jordan that I had originally started working on a different design that might work better for him if sagging was a concern.  This was/is the starting point of my bag of parts kit.   I had started out designing pipe guides that would slide over the edge of a board to serve as the rails, and even cut out a full set for prototyping before I veered off onto the current concept.  I plan on coming back to this concept after the current machine is done, in fact I think I could probably build a variant of the current machine using this rail design with minimal effort.   In the meantime thought I would share the idea, so I found the pieces in the garage and took a few pictures.

Original rail prototype 1

Original rail prototype 2

Original Prototype Parts

If this idea looks interesting please feel free to run with it, I won’t be offended   Just be aware that I will be venturing down this path as well, so you might have some competition.

I have completed all of the lead nuts and carriers, bearing blocks, and added a support to the bottom of the Y axis to firm things up.

ISO View 1

Problems

I had some issues getting the Z carriage assembled and square, which was weird since it went together easily when I did the prototype.  I think it must have something to do with the paint, so I will need to adjust the parts with a little more leeway.

Sitting on the bottom support are the bearing blocks that will go on the motor side of the lead screw, so thats 3 bearing supports on the Y and X axis.

ISO View 3

XZ Carriage

The Z and Y slides are a bit tight, but I think I can do some fine tuning by tightening the bolts holding the bearing slides in to micro-adjust the tension.  I have found that sides are looser on the ends, so I have had to tighten things a bit more than I would like too to make everything snug.  Again I think the paint has something to do with this, as it was fine in the prototype.

Side View 1

I have had a few cracks develop when I tighten the clamps down on the pipes.  So far I have just forced some glue into them and put a clamp on them, but I may look into to using something like Starboard (HDPE) for the clamping parts in the future.

Oh Crack!

Still left to be done:

1) Cut down lead screws and attach couplers.

2) Add supports to table and drill appropriate holes to connect it to the machine.

I picked up some EMT conduit that I plan on using to support the table, I was going to use some shelving uprights, but the conduit is much cheaper, if a bit more work.

3) Attach motors and electronics, and get EMC2 up and running.

4) Cut mounting brackets for the Ridgid R2400 router, and attach it to the machine.

Not sure when I will get more time to work on this, so the next update may be a few weeks from now.

Here are some additional pictures of the current state of the machine:

Front View

Rear View

ISO View 2

Side View 2

A running theme in my building process is budget, I am always trying to build adequate parts myself instead of buying them.  This has two goals, 1) Save money, 2) Learn how to create the parts I need so I can replace them as needed, and build more for future   machines.  This week’s project was couplings, specifically I needed four 1/4″ to 1/2″ couplings.  I am modeling my attempt after this: DIY Coupling, and my own prior experience with using 1/4″ brass sleeve bearings for my first machine.

I decided to try and find some aluminum tubes that would fit the 1/2″ acme rod and 1/4″ motors shaft that would also nest inside each other.  I found what I was looking for at OnlineMetals.com, and order the following:

0.75″ OD x 0.125″ WALL x 0.5″ ID 6061 T6 TUBE
0.5″ OD x 0.125″ WALL x 0.25″ ID 6061 T6 TUBE

They arrived in a week, I opened the box, took out the tubes and… the 1/2″  OD tube did not fit inside the  1/2″ ID tube… <*despair*> …If I only had one of they little metal lathes I could fix the problem.  I have a drill press, and some 1/4″ nuts and bolts, instant vertical lathe, game on.

The Tubes

The Tubes part 2

I started by cutting 4 – 1.25″ pieces of 3/4″OD tube and 4  – .75″ of the 1/2″ OD tube.

Tube Pieces

I then needed to take a little bit off the width of the 1/2″ OD tube pieces.  I did this by putting a bolt thru each piece, securing it with a nut…

Ready for a spin

and then placing them in the drill press and using a file to to remove a little bit of material at a time until they fit snugly into the outter tube, I also used a piece of 220 sand paper to give a nice smooth finish.

Tool Abuse

The pieces now fit together and are ready for tapping.

They fit now

Did I mention I hate tapping stuff, especially when the taps are small.  I got the first one tapped without any issues, but I managed to break the tap off in the second one.  The attempt at removing the tap with any/all sorts of gripping tools only broke it to the point where I could not get a hold of it anymore.

I decided to just cut another set of parts and be done with it, which would have been great if I could have managed to cut straight.  I usually use a hack saw and a plastic miter box to cut the few pieces of aluminum I need, which usually works OK, but I did not manage to cut straight on any of the 4 parts I cut that night…argh much bad language ensued.  So this is what I ended up with:

Tapped with a set screw

You’ll notice the left most one has a definite lean to it, it really won’t make a difference since the tubes are straight, but it bugs me.

I see a chop saw in my future.

A quick test on the threaded rod and a motor shaft and I am good.

Lead screw test fitting

Motor shaft test fitting

I plan on drilling thru the coupling and rod and using a #6 screw and nut to secure the lead screw to the coupling, which is what I did on the first machine, but there is no reason another set screw could not be used, this particular tube has a nice thick wall, and of course there is always locktite.

Random bits…

I found some 1/2″ ID brass sleeve bearings that a 1/4″ nylon spacer fits perfectly in at my local ACE hardware, I may buy a couple and give it a go.  It would cost about $4 a coupling, but that is still cheap, and I think you could get away with no cutting by letting the spacer hang out of the brass bearing a bit  (towards the motor).  I’ll post the results if I head down this route.

I am also going to try and remove the broken tap, I’ll post how that goes as well.

And finally here is a picture of the current machine build with the table on top (just test fitting), the one thing I noticed is that once I add a spoil board I have maybe 2″ for material, which is not what I intended, but will work for now.  I will cut out new legs with a lower table once I have this thing operational.

Current picture of the black and yellow beast

I should be posting another update in the next week or so, so until next time…

You can find lead nuts starting at ~$7 on ebay, anti-backlash lead nuts from ~$16 from dumpstercnc, and up from places such as roton and other places geared towards commercial customers.  I was looking for a cheap solution that I could make myself, and decided to try using some nylon spacers you can find for about 60 cents each at Lowes and Home depot.  This did involve buying an 1/2″-10 AMCE Tap, these are not cheap, the best deal I found was on amazon for $35.  I could have just bought a cheap set of 4 off of ebay for $28, but I am hoping this will allow me to create them myself and save money on future machines.

Nylon spacers

The first thing I did was create a jig using my existing machine so I could drill the holes for the necessary screws consistently.

Lead nut jigs

You place the spacer in the jig…

Spacer in jig

Add the top…

Add jig top

Then tighten the 2 sides together with a few screws and drill 2 of the screw holes using a 1/8″ bit.

Drill screw holes

These holes line up perfectly with the screw holes in the lead nut carrier.

Drilled spacer and lead nut carrier

Next the spacers are attached to the lead nut carrier using #6 – 2 inch screws, these pretty much thread themselves thru the 1/8″ holes, and everything fits together nice and tight.

Connect spacers to lead nut carrier

Now we tap the 3/8″ holes in the spacers with the 1/2″-10 ACME tap, by doing this once the spacers are attached to the carrier we ensure that the lead screw will have no issues going thru both spacers smoothly.

Tap spacers

I added 2 nylon nuts to ensure everything stays together, but I think these are unnecessary.  I used nylon nuts since they are very close to the lead screw, and I didn’t want to take any chances damaging the screw with metal ones.  I then attached the lead nut carrier to the X axis assembly using 1/4″ bolts that screw into Tee-nuts that are part of the X axis assembly.

Install lead nut carrier

Now we take a step back and say “hey that’s not too bad”

Take a step back

The lead screw turns very easily, and there does not appear to be any appreciable backlash at the moment.  If backlash does become an issue, I plan on moving the second spacer out a bit by adding a few additional nuts to adjust for it.

This is my first attempt, it looks like it will work, but I also have some 1.5″ acetal rod waiting for attempt number two if need be.  If neither of these work out, or I find myself with a surplus of cash I may end up buying a set from dumpster CNC, but I figure it was worth a try.

I still have to finish assembling the other lead nuts, cut the rest of the bearing blocks (10 of 12), and create the DIY couplings (metal tubes should be here tomorrow I hope), and come up with some sort of support for the 2′x4′ table, then I will be almost finished…

I have already veered of my original intent a bit, but if this thing actually works well, I have plans on simplifying  a few areas to make it so I can ship a fairly small kit with the end user supplying a number of standard size pieces of lumber, well see what happens with that.

The router is designed to have a 24″ x 48″ cutting area, the machine dimensions are ~36″ x 60″, all the rails are designed to use black pipe and roller bearings, as in all things I work on, containing costs is one of the prime objectives.

This is about where I stand at the moment, I just added the z rails right after this picture.  I have a fair way left to go, the 1/2″ acme lead screws are here, the 4 270 oz motors are here, I am going to attempt to make my own lead nuts and couplings, so much work still lies ahead, I will do my best to post updates as the major pieces come together.

The build so far...

This was my initial proof of concept prototype, and it was solid enough, so I decided to continue cutting the parts of a prototype for each axis, there were a number of assembly points along the way.

1st Prototype Assembly

2nd Prototype Assembly

Final Prototype Assembly

At this point it seemed like this might actually work, so I made some final adjustments to the design and proceeded to cut out all the parts need to build the monster.  I then built the table you see them sitting on, and for some reason decided I should go ahead and prime and paint them…  not my brightest idea, priming took forever, a lot of small pieces with way too many edges to seal.  The yellow paint was a pain as well, 2 to 3 coats to cover, next time I am using dark blue

Fresh cut parts

Primed and ready for paint

Painted and ready to build

With painting finally finished, I assembled most of the major pieces fairly quickly…

Rail Assembly

Rail connection

Rail connection backside

Gantry Carraige and Z Axis

X Axis

Z axis

Z Carriage

This is just a place for me to put various things that for some reason or another I want people to have access to.