Logos Attached
 

See below.

Nice Nice Nice!!!

Dust foot cutting
 

Did some experimenting with dust foots. I actually had bought a dust foot from KentLLC, but it is not going to work with my machine so I am making my own now.

I have not really liked the standard dust foot design with all that open space. I wanted something that draws up directly over the tool bit. Below is a pic of what I cut today. It is made from 3 layers of 3/4 inch plywood. The top is the adapter to fit over the spindle and attach the hose. The middle layer forms the duct. The bottom layer closes the duct and has an opening centered around the spindle. I will need to get some smaller magnets to hold it all together before I test it.

3 layers is too tall for me. My dust shoe is only 1 layers thick. I don't like my spindle body to go through the dust shoe hole, just the spinning part. to keep opening as small sa possible.

Looking good.
You have Logos and you have cut.
You must be due a number.:)

Ken,
For my spindle,the two bottom layers extend just to the end of the shaft. I hope the Z-axis never tries to go lower than that.

What I have not figured out is where I can buy some bristle material. I will still need a ring of that around the opening to keep chips from being hurled away.

Will the Z hard stop prevent it from going that low?
I think the "sweep" material is available from Home Depot, etc. as a sweep for door bottoms? (At least I think I have seen it there, going to be needing that myself). The dust foot design looks nice.
Mark

There is a hard stop for bottoming out, but that is just to prevent the slide from going past the guide rollers. Beyond that, there is nothing to prevent the spindle shaft from crashing into the work. Of course, long before that there will be other mayhem like broken router bits.

I guess, I meant ...could you make a hard stop that corresponds to the dust foot. As a fail safe, so the dust foot can't hit the table?

I suppose you could drill an extra hole in the support tube to create an additional hard stop to prevent that. Or add an adjustable electronic stop.

The only way I could see there being an issue in normal operation would be if you were cutting really deep pockets where the end of the shaft could go below Z=0.

For my uses, I do not really expect to run into that problem. If I do, I will have to use a different dust foot design.

Keep experimenting, you will find a position which you don't need any hard stop or limit switches.
my seldom feed my spindle very far into the dust shoe, usually only the collet is inside the dust shoe. & the dust shoe opening is smaller then my spindle body. hence I don't expect my spindle body goes into the dust shoe.
My logic is simple, if my bit is very short, it only means the bit is very small diameter, & wood dust will not be a problem without dust collection. & this works for me. others may have their own ways.
I had my fair share of dust shoe getting caught during cutting... :(

Anything else for a serial number?
 

I have logos installed and have shown the machine cutting. Is there something else I need to do to get a number for the machine?

Wake Mike up, probably...

Time!!!!!!!!!!!! Just kidding. Rest assured Mike will get you one though probably not as fast as you would like.

I have AWOKE !! Awaked ... Awaken .... uuuu :) !!! Congrats !!! You get #118

Congratulations # 118.
Prepare for a changed life.:D

Al, hope you are not affected by the quake lately.

Builder's Log Update
 

Congratulations, DB on completing your MechMate and earning Serial #118.

Here is the Updated Builder's Log with your entry added.

Please look it over and let me know any changes you'd like to make.

Thanks Mike. You can go back to sleep now. :)
Thanks everyone for the help and encouragement.
John, everything looks good with entry.

Congrats on #118, sir.
Very well done.

Thanks for the concern Ken C.
It was to the North West of here.
Some felt the quake here but I was unaware of it.
One of the strongest for a long time.
The MM is fine and working well.:)

Congrats on 118

Congrats on #118.....that's a fine number!
Mark

Congrats on #118, I myself am aiming for 120.

Congrats! :)

Congrats DB! :D I was wondering who get the next number first. Sleepyhead Mike can go back to sleep now.

Oh, Bruce you can be number 119 if you want it bad enough...lol

Not if the control box has its way Tom :)

Welding Distortion Demonstration
 

I saw this video posted today on the welding tips and tricks channel on youtube.
A laser pointer is used to show how steel distorts as you weld it.

https://www.youtube.com/watch?v=0pf-qQDslhU

Next time I am welding something, I am going to attach a laser pointer to the piece to see how things move around as I weld.

That is the reason why when we need a precision part that requires a weld process, we allow a tolerance so it can be machined afterward. The tension that welding puts on steel is great. You can pull and push the motion somewhat but it all depends on the steel, the grade and quality. I have never seen a laser used to demonstrate it.

Some more setup and comparisons
 

I got the PMDX-107 wired into the VFD yesterday. That will be nice. It was getting a little tedious to have to turn the spindle on and set the speed manually. The only thing I need to remember to do is make sure the spindle is not turned on when I am doing pen tests! I did not make that mistake, but I am afraid at some point I will forget.

I also dismounted the spindle to drill some mounting holes in the spindle mounting block for holding the pipe for the vacuum. I also drilled a few extra holes for any other things I may want to attach in the future. That is one nice about having the big hunk of aluminum block. Lots of meat to drill holes into.

Finally did some real airplane work today. I started drilling holes for four doublers in the center spar. This is basically a 1/4"x2" by 1014mm (mixed units I know) piece of aluminum bar. While I was not going to trust the mechmate to drilling these holes, I did use a pen to layout the holes in one piece and manually layed out the other. These are all match drilled. So the manually drilled the piece I layed out and clamped the other to it.

The result is the pic below. The lower is the mechmate layed out piece and the upper is the manual method. The holes were match drilled together. There is a little offset in the holes in the top compared the lines, because I align to line edges, not line centers.

The conclusion for me is that if I had used to MM to drill these holes, the piece would have been acceptable, but I would not have been happy with the accuracy. There was as much as a 1mm difference between my layout and the MM layout.

I think part of error is due to my not having the steps/mm quite right. I am waiting for a webcam to come in that I can attach to my MM to try to get a better indication of distance traveled.

Part of it also is that the surface of this bar stock is not perfectly smooth and the marker ink had a tendency wick along the grooves some. I think it also affected the tip of the pen.

Essentially there is more tuning to do. I want to see under .5mm error over the full dimension of the table.

You will have most likely 0.25mm backlash with using a spur gear drive. If you are using a planetary drive it will be less. I cannot read the specs on your steppers but I they look like steppers with spur gearbox. Only a belt drive will 'rein in' the backlash as a gearbox has to have backlash or it will tear itself apart. The tuning should be fairly easy to set using 0.005" V-bit and a certified tape. Run the steps per unit function starting at a mark at the front of the table and run the set distance to the end of the table. This will set your steps per inch or steps per mm as close as you are going to get. If you are do indeed have a spur gearbox, make sure you move axis in the direction of travel of the Steps per Unit function will be traveling first before running the function.

You are correct that that I have geared steppers and I did measure a backlash is about .25mm. I was giving some thought to trying beveled gear drive steppers.

Your only hope to reduce it is planetary (3 arc min), harmonic (0 arc min) or belt drive. Belt drive is the cheapest solution.

Belt drive also give more torque, if done properly, a few magnitude more.

Calibration with Camera
 

I finally got a USB extension and was able to mount up my webcam to do some more calibration of the X and Y axis. The camera is a little microscope camera I have had for several years. It fits nicely in one of my extra connector glands.

I used an old eeePC for the camera display so as to not overload the Mach3 machine. I will try the Mach3 camera plugin later.

I am able to get under .25mm over the full range of my meter and 2-meter sticks now. I also checked my backlash. I have about .1mm on the X and about .25mm on the Y. That is going to be due to my using geared steppers instead of belt drives.

If you want to do similar tests be sure to get an active USB extension cable. The regular 15ft extension cables did not work for any of my devices. The active extension cable is basically a single port hub and gets detected by windows as such.

The lower picture shows by how much I am out of square over about 1500mm. So a little more shimming to do around the rollers.

Nice work!

Finally square
 

The Y axis is finally squared to the X axis. What a PITA!
I did not think I was ever going to get it to come out right.

I used a combination of Gerald's instructions for shimming the gantry rollers and a test pattern of 4 X's 1 meter apart to measure diagonals.

That's awesome. I had my rails slotted a little on the Y. I screwed up on the markings for the holes and did not allow for the difference in using the bolt on V rail. In the end it helped for squaring the Y but Gerald's instructions are spot on if you have everything right.

congratulations on your accurate machine.

Downward cut spiral bit and aluminum sheet
 

I made my first attempt to cut some .025 inch aluminum with my downward cutting bit.

The results were not quite what I expected. The bit did not penetrate the aluminum on the first pass. After about three passes it finally broke through, but the behavior is not what I would have expected.

As far as I can tell, I have the bit turning the correct direction. Clockwise looking from above.

Any suggestions on why the bit would be riding over the top instead of cutting through?

The bit I am trying to use is at http://www.amazon.com/dp/B000P4NQGQ/..._26725410_item