1 hour ago, 4DThinker said:

Curious what features you like that you can't find all in one CNC?   Or at least in one CNC you can afford?  

The ones I could maybe afford are in the what you described as "Looks like a toy" category in another topic.

 

The Genmitsu 4040-Pro gets a bit closer, but is still in that category. I prefer having the gantry doing the y-axis over having the work table doing so. Next step up about double the price. 

 

 

 

I noticed that their site options CarveCo subscriptions with their CNCs.  That's one thing I'd stay away from unless you plan on using the CNC for only 3 or 6 months.  IMO subscription software is a bad trend that I wish would go away.  A continuous ongoing income (drain on your wallet) for the company after the original sale. 

As for a $500 budget you'll probably meet or exceed that buying all the parts needed to make your own.   

 

There are websites that will laser or waterjet cut parts for you from nearly any material. You provide a .DXF file with the parts outlines, material, and any specifics like tapped holes or beveled edges.  I realize that I could pretty much order unique parts of my own specific design to replace/improve the frame design of my Probotix CNC.   You could find a design using end and gantry side plates of  aluminum and see what it would cost to get duplicate or similar parts made.  The beams and linear rails are commodities and easily sourced.   

I got my old motorcycle shield mounted above the CNC milling machine. It will swing around 180 degrees depending on where I am to keep metal chips from hitting me when the machine runs.  Screwed a board across the ceiling studs with a hole for a 1/4" threaded rod hanging down directly above the spindle center.  Took an old 2x6 scrap and ripped it to 4" wide, ran it though my drum sander to clean up both sides.  Used my wood CNC to shape the end to match the curved shape of the shield. Sank a threaded insert into the curved end so I could bolt the shield to it.  Found a bag of washers and a scrap block of aluminum to counterbalance the shield and hung this to the hanging threaded rod.  Not conventional protection, but something to do with an otherwise useless motorcycle shield. Spins around without interfering with the movement of the CNC.  Board is slanted 5 degrees so it will clear the Z axis handle. 

4D

 

On 3/15/2023 at 8:54 PM, 4DThinker said:

I noticed that their site options CarveCo subscriptions with their CNCs.  That's one thing I'd stay away from unless you plan on using the CNC for only 3 or 6 months.  IMO subscription software is a bad trend that I wish would go away.  A continuous ongoing income (drain on your wallet) for the company after the original sale. 

As for a $500 budget you'll probably meet or exceed that buying all the parts needed to make your own.   

 

There are websites that will laser or waterjet cut parts for you from nearly any material. You provide a .DXF file with the parts outlines, material, and any specifics like tapped holes or beveled edges.  I realize that I could pretty much order unique parts of my own specific design to replace/improve the frame design of my Probotix CNC.   You could find a design using end and gantry side plates of  aluminum and see what it would cost to get duplicate or similar parts made.  The beams and linear rails are commodities and easily sourced.   

Not sure if I even need the software, as I mentioned in another topic I've got old PC hardware but don't think I mentioned that I've also got software to go along with it. Of course it dates back to W3.11, W95, NT 3.5/4.0. I'll have to find the stand alone copies of AutoCad and other software to make sure what OS they are for but if it ran equipment in the shop, I don't see why I couldn't get it to work for something like this. IIRC some of the software was running 9-axis equipment.

 

As to the hardware, the recycle yard near me has scrapped industrial equipment that I could get most of it from.

 

Sounds like you've got a plan forming on how to end up with a working CNC.  I personally enjoy spending time on such pursuits just to keep me challenged and mentally active. Such was the motorcycle shield project above.  Rediscovered the shield when cleaning out my utility room to make space for the CNC mill and related metalworking tools. I parked it where I would see it every day to stimulate my creative juices.  Finally woke up one morning knowing exactly how to go about using it effectively with the mill. Knew I had all the parts to use on hand, and that I just had to locate them all to turn them into the parts the project needed.  Knew I had the tools on hand that could make it a reality.  

Making a CNC from scratch I've done twice.  A deeper and wider and longer adventure but very satisfying over and over again when small steps toward the end were completed.   Should you accept the challenge but get caught just know we will disavow knowing or helping you and that this recording will self destruct.  Godspeed. 

4D

2 minutes ago, 4DThinker said:

parked it where I would see it every day

I've done that with oddly shaped pieces of wood- setting them on the lathe and repositioning them several times.

4 hours ago, 4DThinker said:

Sounds like you've got a plan forming on how to end up with a working CNC. 

Not exactly sure what I'm visualizing would be called, kind of a cross between a mill, and router with A, and C rotational axis capabilities thrown in to make it a bit more interesting. 

 

4 hours ago, 4DThinker said:

I personally enjoy spending time on such pursuits just to keep me challenged and mentally active.

How's the above for a mental challenge?

4 hours ago, 4DThinker said:

Should you accept the challenge but get caught just know we will disavow knowing or helping you and that this recording will self destruct. 

 

30 minutes ago, Larry Buskirk said:

How's the above for a mental challenge?

 

A worthwhile adventure!   I have a former co-worker friend who was a collector of anything abandoned that might have some yet unknown future use. When he retired he set about making his own Frankenstein CNC from the this and that he had collected.  I visited him a few months back to see the beast in person and was quite impressed.  I asked him what he had made (implying made using the CNC) and he was most proud to show me the guts and workings of that CNC he had made. 

 

If you want versatility in what your CNC can do then a 3-axis (x/y/z) CNC, with a rotary axis (a), with a frame you can open up to clamp just about anything vertically or at any angle/compound angle will give you close to what a 5-axis CNC can do.   I have that with my aging Probotix CNC.  Their updated machine designs are much stiffer and have more Z axis travel for about the same price I paid for mine:  https://4dfurniture.blogspot.com/2016/04/advanced-compound-angle-cnc-clamping.html   

That fixture is pretty slick. 

When I worked in machining at the plant I ran a machine that machined two 4.0 litre inline six cylinder engine oil pump housings at the same time. Not sure if you would classify it as a CNC machine or not. It had dual spindles, and what I can best describe as 6-axis fixtures to hold the housings. It was a Frankenstein creation made in house by our skilled trades. It was made from remnants of a horizontal drilling machine. It replaced a much larger machine that even the technicians from the manufacturer of that machine couldn't figure out when it went down. They spent over a month fighting with it. Believe it or not that Frankenstein machine did the same work faster. 

Often it takes working with/using a machine or other product to understand and see a way to improve it.  That clamping jig of mine was the 3rd iteration after realizing the shortcomings of the earlier designs.  The last update replaced hand screws with cam levers to release or tighten the jig when at the right angle.    The earlier versions were vastly different and much harder to install/use/set/clamp to. 

Edited March 18, 20233 yr by 4DThinker

Looks like I have to figure out backlash compensation in mach3.   I decide to cut a round end on a perfect 1" wide x 3/4" thick aluminum block.  Took my time to make sure the bit was zeroed out exactly where it was supposed to be when I set up the toolpaths.  Preview in Aspire looked perfect.   Started the job and to my eye it looked like it was taking off more on the +y side than the -y side as it stepped in 1/64" or so at a time.  Stopped the job.  Rechecked that the bit was still right against the bar on the -X and -Y sides. when sent to 0,0.  As this was more of a test than a critical  job I restarted the toolpath and let it finish.  I ended up with an arced end that was clearly offset between 1/32" and 1/64" in the -x and +y directions.  Switch to a V-bit to run the chamfering edge and centermarking toolpath.  The center mark should have been perfectly centered 1/2" from each edge. Careful measuring has it 1/32" off center.  Looking at backlash compensation in the Taigtool manual they say to expect as much as .005" backlash in X and Y directions.   

Not too happy.   The manual does explain how to reduce play in the drive nuts, but that means taking apart the X/Y table to get to them. 

This is more on the order I've envisioned.

https://detroit.craigslist.org/okl/tls/d/milford-gmt-cnc-mill-with-wixhc-control/7600331078.html

Most of these type parts show up at the recycle yard.

$3200 seems like a deal for everything included.   Curious why the seller is selling. 

Post now deleted.  Must have found a buyer. 

Edited March 18, 20233 yr by 4DThinker

15 hours ago, 4DThinker said:

$3200 seems like a deal for everything included.   Curious why the seller is selling. 

Post now deleted.  Must have found a buyer. 

I didn't think it would last long myself. 

Got started on adding an E-Stop switch to the mini mill.  Bought one from amazon.  The injection molded ends have so much draft angle on them that the bottom isn't flat when set on a table.  I didn't want to screw it directly to the tool bench, so I made a plywood plate that would both account for the slanted bottom ends of the switch, and have a slot for the C clamp I used to clamp it to the bench top.  Cut it out on my Probotix CNC.   Now I just need to get my wire stripper, solder and soldering gun out to run a cable between it and the controller. 

 

 

4D

Here is the relay I'm using to turn the spindle motor on and off with the toolpaths. 

 

Initially using the Taigtool CNC reminded me of using my old CNC Shark.  It also required manually turning on the router before you ran a toolpath. I'm spoiled using my Probotix CNC that does control the ON/OFF of the router. 

 

This CNC, just like the Shark, has no limit switches or homing routine.  I may add limit switches as the controller does support them. 

4D

Only thing about using that relay box is that it has more features than needed,  I might plug a small LED spotlight into the other normally OFF outlet, to illuminate the project being cut for better video capture.   I have no idea what I'd used the normally ON outlets for though. Makes me think there must be simpler less expensive relays out there with just the normally off outlets. Sure can't find such a beast so far. 

Relay and e-stop additions both have been tested and work as intended. There are backlash settings in mach3 where I can set how much backlash I find on each axis. I'm assuming that when that option is turned on the g-code will be adjusted before cutting to compensate.  I've got a dial indicator, but no rigging to use it,  I either need to buy a rig or find something I can use to hold it up to measure the movement of X an Y axes.  

On 3/17/2023 at 6:36 AM, Larry Buskirk said:

As to the hardware, the recycle yard near me has scrapped industrial equipment that I could get most of it from.

Got an email from Woodsmith about plans on how to make your own CNC.  https://www.woodsmithplans.com/plan/cnc-router/?utm_campaign=WSM - IP&utm_medium=email&_hsmi=251001902&_hsenc=p2ANqtz-_tRvCNBULq1KBtfbtgvBaCQMVyuaNyvSHGadN8B--xCgOwIcpXwc3CA9yfobWKX-u8hHVZnCxxii-URJVRvUInUCux-w&utm_content=251001902&utm_source=hs_email

 

Of course they want to sell you the plans, but the price seems reasonable if the plans are complete.  Mentions an "off the shelf" hardware package for the project. Hopefully that's the controller and steppers needed. 

Edited March 24, 20233 yr by 4DThinker

Received a magnetic base holder for my dial indicator. Although X and Y table isn't magnetic I was able to stick the holder to the frame of my Taig CNC mini milling machine to see if I could use it to find out how much backlash my machine has.

 

1st challenge was realizing that my digital dial indicator is far more precise than the CNC is. My indicator shows 0.0001" precision.  A 0.1" step might show 0.0994" of movement. Six 10 thousandth "error", but within the CNC's .001 to ,002 precision rating.   

I'm trying to find out if there is any way to limit the accuracy to 1/1000.

Second challenge was realizing that between the thread pitch and stepper moves the CNC can't resolve to .0001", but the math required to "average" .1" in 10 steps or .01" in 100 steps over 1" each step my be slightly more or slightly less than than the 0.1" or 0.01" expected. 

 

So I've order a less expensive and less precise true dial indicator from amazon.  If my digital calipers can't measure 10 thousandths, and I personally can't see or feel a 1/10000" difference in a part dimension I see no real value it worrying about such precision.