Mortise and Tenon Machine?

| Morris Dovey said: | || I've been thinking seriously about CNC conversions for mini-mill || (HF) and mini-lathe (Griz) for making small metal parts for the || woodshop. Either can be built using all new components for under || $2K. I have a programming background and was able to write the || driver software for a $200 controller card in about an hour. It's || /not/ rocket surgery! | | What program(s) do you use to generate the plot files? | Do they produce Gerber output, or something else?

With the ShopBot, I have two approaches. The first is fairly conventional: I make drawings in DesignCAD and export them as DXF files. If the drawing consists of toolpaths, I can hand the DXF directly to the SB cutting program. If the drawing consists of edges (a more usual type of drawing) I use a program called PartWizard (provided by ShopBot with the machine) that interactively converts drawing to part program, which is then fed to the cutting program.

The second approach isn't so conventional. With this approach, I write C programs that output a file of part program commands. This lets me take advantage of all the capabilities of a general-purpose programming language to do things not readily done within the limited capabilities of normal part programs.

I've also hacked my cutting application to allow me to invoke and pass command line parameters to an external program from within an executing part program. This allows me to (interactively) generate and execute part program code "on the fly".

The second approach "unhooks" me from the machine vendor, since I can as easily emit g-code as the proprietary ShopBot codes.

I think more than 99.99% of executed commands are 'move' commands, so it doesn't appear any more difficult to call a controller driver with parameters for a tool move than to write a tool movement command with those same parameters to a text file...

| I have considered this very thing, not only for woodworking, but for | drilling numerous tiny, precision holes in printed circuit boards.

And if you add motor speed control and replace drill bit with a router bit or end mill...

| Started building a small X/Y/Z drill plotter back in 92, but never | finished it due to various moves around the country. Finished most | of the software, but never completed the hardware. It read Gerber | files. The cost of big stepper motors and such relegated it to the | back burner - I was going to salvage the parts from old equipment, | but never found a good set of adequate matching motors.

Important things have happened since then - E-Bay, Google,... :-)

|| There was a recent thread with a Dutch OP who built a CNC router || and | | I noticed that as well. Looked over some of his pages, and meant to | reply to him, but life got in the way...

Well, I think I'd have done it differently (which just goes to show that everybody's an art critic) but the important part is that _he_ got the job done simply and inexpensively - and he was willing to share with the rest of the world. Once the basics are in place, one can always make refinements. I think he merits at least an "attaboy!"

Build your machine!

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

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Morris Dovey
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"Robatoy" wrote [snip]

Rob,

The Colombo spindle is a nice upgrade, but don't let that hold you back. I've done everything from machining an entire production line system (5 modules) from 1", 1-1/2" and 2-1/2" HDPE, to cutting Polycarbonate doors, to engraving equipment nameplates (down to 14 point text) with the same machine.

The learning curve is the hardest part ... we literally learned while building the production line equipment. Using the provided software with the Shopbot, and using TurboCad as the design front end, we were able to use 90% or better from each 4' x 8' sheet of plastic. We made structural panels, conveyers, robotics parts ... you name it, we did it. Even engraved the company logo onto the front and rear panels of each module for that extra nice touch. Countersunk holes for shoulder bolts was no issue ... just another layer in the drill file (each depth was cut as a separate layer ... the so-called 2-1/2D method). My boss did most of the toolpath layout and used the same kerf twice whenever possible ... minimizing waste. We learned along the way that plastic will warp just like wood if you take too much out at once and don't give things a bit of time to relax ... and don't trust that 1" extruded plastic to be closer than say +/- .030".

Lots more to encourage you with ... especially Shopbot support ... had one channel go dead in the middle of cutting some conveyer sprockets, a quick call to them and they told me how to use the spare channel until I repaired the main drive channel. Great guys.

Our purchase was made much easier by the fact that the factory is an hour and a half away ... we went for an on-site visit, and I then drove back and hauled the entire shopbot back in my minivan. Assembly took two days (mostly by myself), and to this day, I'd do it all over again.

Regards,

Rick

Reply to
Rick M

A very solid day's drive for me. I am 1 hour north of Detroit MI on the Canadian side. I would still pick it up myself and spend some time catching some training which I would also be happy to pay for. I would insist on assembling the thing myself as I plan to maintain it.

The steel will be done here. Half the price by people I know and trust. I'll even get it powder coated for that same price. Got a millwright in the family as well.

Everything I'm doing is focused on the peripheral equipment so I can feed this thing properly when it gets plopped into the middle of my manufacturing centre.

If I have another year like 2005, I might be building a complete kitchen per month by January 2007.....by myself. I have a wonderful supplier for my doors, but there is one weak link in my business plan ---> a reliable/affordable edge-bander which will do vinyl as well as solid wood edging.

So much for Freedom 55 retirement, eh?

Hey.. a guy can dream, can't he?

Reply to
Robatoy

The Morris Dovey entity posted thusly:

Hmm... sounds interesting. My situation, being a hobbyist only sort of dictates how much I can spend without the profit justification.

I'm a programmer as well, and do mostly assembler on micros, VB and some C/C++ on PCs (Windows, usually, but prefer Linux). I don't know if I have enough confidence in my programming abilities to buy the hardware 'on spec' and to write the software later.

Was that on the ShopBot or CNCZone forums?

$1K sounds like my kind of price. For a few years, I made vinyl signs, and kept looking at my vinyl cutter, thinking "I could make a CNC router", but never did try. I even bought a video from a fellow who had made a CNC table using (of all things), alternators as stepper motors. Misplaced both the video and his name/email address years ago, though.

I'll look for the forums.

I do, and thank you for the knowledge.

Larry

Reply to
Oleg Lego

| The Morris Dovey entity posted thusly: | || Oleg Lego (in snipped-for-privacy@4ax.com) said: ||| ||| But you can sure by a lot of jigs, fixtures and accessories (not ||| to mention routers and tables), for what you'd have to spend on a ||| ShopBot. | || Starting out, I was afraid to consider used equipment and wasn't || aware that there were some really good buys to be had. Had I known || how to look for used equipment, I'd have paid far less (perhaps a || fifth or a fourth as much) for a good used machine. | | Hmm... sounds interesting. My situation, being a hobbyist only sort | of dictates how much I can spend without the profit justification. | || If I'd known what I've learned _since_ buying my machine, I'd || almost certainly have paid to have a table and gantries welded up || and then built the rest myself. Three-axis controller cards and || stepper motors are available off-the-shelf. | || I've been thinking seriously about CNC conversions for mini-mill || (HF) and mini-lathe (Griz) for making small metal parts for the || woodshop. Either can be built using all new components for under || $2K. I have a programming background and was able to write the || driver software for a $200 controller card in about an hour. It's || /not/ rocket surgery!

There are pix of both machines at Steele's website (link below). | | I'm a programmer as well, and do mostly assembler on micros, VB and | some C/C++ on PCs (Windows, usually, but prefer Linux). I don't know | if I have enough confidence in my programming abilities to buy the | hardware 'on spec' and to write the software later.

Ok, then take my approach - download the controller interface spec and write the software before you commit the funds. I found hardware conversion kits at

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downloaded the I/F specs and wrote a driver skeleton and some simplistic software unit test code to see how difficult it might be - and it wasn't! I wrote the code on a Linux system using nedit and gcc; but it works equally well under MSDOS using Borland TurboC 3.0 (a blatent plug for writing ISO/IEC-9899 compliant C code). Go ahead and give it a shot - and e-mail me if you get stuck. I could send you the code now; but then you'd lose the brag of having done it all yourself. :-)

|| There was a recent thread with a Dutch OP who built a CNC router || and | | Was that on the ShopBot or CNCZone forums?

It was HERE! :-)

The gentleman's name is Martin de Roode and his website is at

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|| I'll guess that machine put him out of pocket less than $1K, and || could be modified (only slightly) to become a wonderfully flexible || CNC joinery machine capable of out-performing any/all of the || off-the-shelf passive joinery machines - and produce joints || impossible/impractical with templates. | | $1K sounds like my kind of price. For a few years, I made vinyl | signs, and kept looking at my vinyl cutter, thinking "I could make | a CNC router", but never did try. I even bought a video from a | fellow who had made a CNC table using (of all things), alternators | as stepper motors. Misplaced both the video and his name/email | address years ago, though.

My kind of person! Martin used drawer slides as linear bearings - something that'd never have occurred to me, although it seemed obvious after seeing his machine. Alternators - hmmm...

|| Best of all, there's a _lot_ of free help available. The ShopBot || and CNCZone forums (both of which welcome visitors) have been of || considerable help to me. | | I'll look for the forums.

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Dovey DeSoto Solar DeSoto, Iowa USA
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Reply to
Morris Dovey

The Morris Dovey entity posted thusly:

Sounds like a plan.

Found it. Actually, as soon as you mentioned the drawer slides, I realized I had independently found Martin's site a few weeks ago, and filed it under "stuff to look at".

Yes, I wish I could remember the fellow's name. He did some mods to the alternators, if I remember correctly, though it seemed like it was minimal.

Larry

Reply to
Oleg Lego

| Yes, I wish I could remember the fellow's name. He did some mods to

I don't know if it's the same person, but there's some how-to info at

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Dovey DeSoto Solar DeSoto, Iowa USA
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Reply to
Morris Dovey

The Morris Dovey entity posted thusly:

That's not him, but it's probably a similar mod. I took a look around on Google, and I'm pretty sure the fellow I mentioned was John Rees (found references to John Reese as well). Don Lancaster had a 'flutterwumper' article or two that mentioned him and gave a hint or two of the mods necessary.

John's video was a complete description of a sign-making system, in an hour-long video. I don't know if the accuracy would be good enough. Cutting 2-4ft. high styrofoam letters allows for a lot of inaccuracy.

I think I know where my video might be. I'll see if I can get in touch with the borrower. :-)

Reply to
Oleg Lego

The Morris Dovey entity posted thusly:

Aha! Have a look at

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for more info. The article starts on page 116 (Acrobat page, or 44.2 article page).

Reply to
Oleg Lego

| Aha! Have a look at

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for more | info. The article starts on page 116 (Acrobat page, or 44.2 article | page).

Downloaded it last night - thanks! I think I'll stick with store-bought steppers so I can have the 400 step/revolution resolution.

Just to keep all of this interesting (and more than just hot air) I hand-coded a couple of part programs last night that should let me cut common, half-blind, and (non-mitered) full-blind dovetails using only a straight bit. Dovetail height, width, angle, and spacing are set as parameters; and the code self-adjusts for the size of bit used. What's fun is that there's no 'round' anywhere except in the corners, and use of a sufficiently small diameter bit should make that difficult to see.

It'd be fun to build a small CNC joinery machine that could be dedicated to gnawing on the ends of boards like this. With a bit of luck, I'll have some pix to put on ABPW tonight. :-)

Hi-ho, hi-ho, ...

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

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Morris Dovey

The Morris Dovey entity posted thusly:

Probably just as well. The resulting stepper not only has a lot fewer steps per revolution, but not a lot of torque. They are just not made for that duty, and while they will work, are not anywhere near as good as real steppers.

If you happen to know, what is the holding torque on your ShopBot steppers?

Reply to
Oleg Lego

| If you happen to know, what is the holding torque on your ShopBot | steppers?

I don't know. The only clue I have handy is a comment in the Users' Guide that they exert a "Linear force 60-75 lb. at cutting speed, depending on gearing."

Today I encountered my first problem (in over two years) with the machine and plan to talk with the factory folks tomorrow. I'll ask about holding torque.

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

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Reply to
Morris Dovey

| Just to keep all of this interesting (and more than just hot air) I | hand-coded a couple of part programs last night that should let me | cut common, half-blind, and (non-mitered) full-blind dovetails | using only a straight bit. Dovetail height, width, angle, and | spacing are set as parameters; and the code self-adjusts for the | size of bit used. What's fun is that there's no 'round' anywhere | except in the corners, and use of a sufficiently small diameter bit | should make that difficult to see. | | It'd be fun to build a small CNC joinery machine that could be | dedicated to gnawing on the ends of boards like this. With a bit of | luck, I'll have some pix to put on ABPW tonight. :-) | | Hi-ho, hi-ho, ...

As usual, everything takes longer and costs more. Photo of first half-blind dovetails finally posted to abpw.

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

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Morris Dovey

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