My Newest Desktop machine

[TheRobberDotCom]

Hehe... anyone else notice that if you add an A to SPM Controls, you get Spam ? :P I think it's sad that there's so much spam

[microcarve]

Hehe... anyone else notice that if you add an A to SPM Controls, you get Spam ? :P I think it's sad that there's so much spam

LOL!

I saw that and thought the exact same thing. Looks like their spm control
is broke....

(The thread got spmmed yesterday in case anybody missed it. The Great
moderators here fixed it quick!)

I haven't got much done on the Big machine lately. I've had a terrible
flu for several weeks and that's slowed me down. Mostly working on
A4 parts...(one will be available very soon if anyone's interested)

I have been doing some design work on 'Parts Kits' when I have time.
There's several interesting things that I hope to show pretty soon.
I'm trying to get some plans worked up too. It's all taking some time,
but sooner or later, there'll be something to show for it all.


John

[microcarve]

Here's one of the kit parts under consideration. I still have to
make several of them before I'm sure of them, but the prototypes
work perfectly.

It'd be nice if some sort of inexpensive linear slide for round rails
could be made. This is very, very close, but making them in a
practical sense sometimes changes an idea from Great, to near
useless....


John

[dertsap]

, there'll be something to show for it all.

GOOD !
I've been waiting for you to update this thread , it always makes for good reading

[TheRobberDotCom]

+1!

[microcarve]

I've been doing a lot of sketching and checking and questioning...
To see if the machines I make can be improved on and how to do it.

I think the A4 is about as good as it can get. I've looked at changing
materials and sizes and positioning. But it's "right". Even the use of MDF
in the design is the right choice. Round rails as well.

The "Bulldozer" design is also a very practical and hard use machine and
it'll work very well using thicker MDF stair treads in it's construction. I just have
to go get more materials to get mine rebuilt into the new design and then
I can show it doing some real work...

Then I have an idea for a smaller bulldozer machine. The aluminum plates that
connect all the easy to make rectangular parts are as bulletproof of construction
as I've seen with MDF. Even better than glue I'd say. The test parts are extremely
rigid and strong. It could fall off the back of a pick-up truck and still be intact.

There's an endless supply of stuff in the works. Time is the only thing that's
stalling lots of projects. Well, the flu is a big PITA too....


John

[Mr.Chips]

It's good to see you back John. I always enjoy seeing your latest improvements to an already excellent design.

Have you done any more with the urethane ball screw nuts, I'm anxious to see the data on the backlash.

Hager

[microcarve]

Thanks Hager!



I haven't got the ballscrew in use yet. I think I want to put them
on the Bulldozer machine when I 'upgrade' mine, so I need to order
a couple more of them.

The general idea is to make as tough -and- precise of an MDF machine as
I think I can. With the 30mm rails and those 5/8" ballscrews....using the
plastic nuts....I'm pretty sure that'll do it.

I've still got to order some stuff and go get some more treads from Lowes.
There hasn't been much interest in the big machine so, I haven't got very
far with doing it yet. But I'm so sure of it that I will before long. The "quickie"
version of it I have, worked so well that it'll probably end up as my primary
use machine. 24 x 15 is a really useful cutting space...


John

[microcarve]

Back when I put the mini mill head on my existing bulldozer...
I learned a lot about just what sort of forces are involved with metal
cutting.

http://www.cnczone.com/forums/diy-cn...achine-22.html

I'd intended to use the mill head for just plastics, but maybe some aluminum
parts as well. There's no quicker way to see where any design problems are
with a machine design than trying to use one of those mill heads with
some large end mills.

For one thing, it weighs about 35 lbs when it's in place. Using a 2 start
1/2-10 acme screw....it's *surprisingly" Easy to backdrive with the weight.
I wouldn't have thought that possible with any 2 start screw. 4-5 I'd expect,
but not 2.

I also knew well ahead that my bridge wasn't ideally bolted in place. So I
was prepared for some crappy performance. It was worse than I'd expected.
Basically Not useful for aluminum.

With the ballscrews and a re-work of where the design problems are, I
think it could work....maybe...well enough for some aluminum. But I *know*
the big Bosch router works well enough, so I'll abandon the mill head for
now.

I really like how easy it is to get that Bulldozer design all aligned so well
and how rock solid it is. It's very easy to access any part of it to do any
add-ons or maintaining.

I want to experiment with making some larger aluminum parts and the Bosch
will handle those O.K. I also want the rigidity of the fixed bridge. And to see
just how well the plastic ballscrew nuts will maintain their "anti-backlash".
After all the machines I've built, I think that's one of the most solid and
easily built designs that can be done in MDF.

I made my first one in a big hurry in a couple days. But I want to make it
much better now that I've used it for a bit. It's just a good all around
design for tons of stuff. And...I've been asked about guitar bodies many
times. I'd guess that that'd be an ideal machine for that. It should just
"bulldoze" right through any hardwoods.

We'll see once I get mine done.
Weather is getting nicer. That's sure helpful....


John

[microcarve]

.








Here's a couple pictures of the latest A4 machine...

This one's available if anyone's interested. I made some new jigs
and fixtures to make reproducing them a little easier, so I'll sell off
this one and see how well the new tools work on the next one.

They're still a bit too time consuming to make, but I'm working
on simplifying that...

Anyone interested can write me at -- john at microcarve dot com.


John

[leaveme]

Hi John,

What is the size of your Z axis drive/end plate...if it is not business secret?

[microcarve]

Nope, no secret...

It's 3" wide x 2.75"

The bolt hole pattern is for Nema 23 motors so it starts
3/8" from the front edge so whatever tool holder used
will have clearance.

Z has 3" travel and is tapped to take any tool holder
that Probotix makes. I've been recommending the Bosch
Colt holder from K2CNC due to it being all metal and
reasonably priced. Their new one is a little different from
what's shown on their web site....last time I looked.

So, a fair range of different routers are easily bolted right
on with the choices in holders that are available...


John

[muqtadir]

Hi John
Can you please give me the price of this nice A4 size router with full details ?
Thanks.
A. Muqtadir

[microcarve]

Hi John
Can you please give me the price of this nice A4 size router with full details ?
Thanks.
A. Muqtadir

Hi A.

This one will go for $489 + shipping from 30429...(Hagen Georgia)
via USPS.

Shipping to Saudi Arabia is $215.

It cuts approx 12 x 9 x 3.5"

It needs an electronics kit and motors, software and a spindle...
(Recommended: Bosch Colt used with a holder for it from K2cnc.com)

Those extra things come from makers/suppliers who are qualified to
support them...as I'm no electronics or software expert, someone is
much better buying those things direct...

This machine only has a single coat of paint. It will be fine like it
is or it can be repainted again.

Anyone interested should write me at john at microcarve dot com


John

[microcarve]

That A4 machine is gone, but I'll start another in a few days when
replacement materials and supplies get here.

Thanks to all who were asking about it....

I'm afraid I've reached some of the limitations with building nice
small high quality machines. The gotcha's involved are the big problem.

There's the main one of whether you try to upgrade it.....or downgrade
it to make it cheaper. Big problem is there's a certain amount of work
that must be done regardless of what sort of material is used, and the
difference in cost of the better material isn't enough to warrant using cheaper
materials.

For example....

Rails. Drill rod can be used and it costs a good bit less. But, a LOT of time
is spent polishing and smoothing it. It's a big crap shoot whether it'll
even work at all. Way too much time goes into getting cheaper materials
to work as well as it really needs to.

A Good Z axis is extremely important for ultra fine details or even some
aluminum milling. Those parts all need to be carefully milled flat and square
in order to work as well as they must. Lots of time in a Z axis. One using less
expensive materials still requires the same attention to detail and mill work.
So far, it's not worth the trade off in time alone.

Frames are well within their limitations and very very strong rigid and reliable
in these small design sizes. Those are cheap & fairly easily made. Changing
some of the parts to metal will make the machine "appear" to be "better", but
actually don't do a single thing as far as improving it goes. They do Look
Good, though....I may try that a little later just to show what it looks like.
It does add some extra cost$$, though...

All the extra aluminum plates that have gradually been added in have been
a true improvement. They're time consuming to make, but they make enough
of an improvement to warrant the material cost...which isn't bad.

Making couplings from scratch is still a PITA, but they simplify things...and
actually save a good bit of $$...and make it all easier for the machines owner
to get things aligned easily. Those have a single 1/4" bore...which is good
for making them, but it also means each leadscrew has to be turned to the
bore size. But doing it all --and taking the necessary time-- on the lathe assures
things get aligned correctly.

All in all, there's not much that can be downgraded for a cheaper machine, and
the few things that can be upgraded don't add anything more than a cool
cosmetic appearance. And higher costs...

There are 5 A4's out now and it's turning out to be a really good machine.
It's big enough to be very useful and still small enough to be good for places
limited space.

I'll start on another as soon as I get the materials in.


John

[atwooddon]

John, those are interesting points and seem to be quite in line with what is going on in the small CNC 'market'. There a several 'cheap' machines out there in the same cost range you are quoting. However, you don't have to look too hard at them to see the obvious issue they will have which is rigidity. That is the single biggest problem I have dealt with in my initial DIY machine and the larger machine(s) I know own. I upgraded from my DIY machine to a MDF framed commercial model that is very similar in design to yours and have had good luck with it. But, I do understand it's limitations.

After using it for about 18 months now, I have decided to go a different route based on the phsyical limitations of my current machine. The majority of what I want to cut will fit easily on my current machine, but I do often run into problems with larger pieces I want to mount and cut. Having said that, I also want a smaller, very rigid machine for the more intricate work, or even cutting softer metals like aluminum. So, I have decided to build a larger machine based on MDF designs out there now AND build or buy something like the A4 for those smaller items. The smaller machine will probably get more workout than the larger one, but I will still have the ability to go either way. I also know I will probably give up some rigidity in the larger machine, but for what I use it for it will do fine.

Thank you for your efforts here on CNCzone, I really enjoy following your work and development.

Don

[microcarve]

Thanks Don!



One thing I keep trying to do is justify making changes
to the A4 design to upgrade it. It's those gotcha's I mentioned
that makes it un-practical to do so.

It quickly adds a lot of costs and 2-3x the end price of
it and there's little to be gained. It turns out to be a
completely different machine.

I realize there's many of us who just don't like the idea
of MDF in anything that's referred to as a "machine", and
I can actually see their point....in many cases.

But, in this particular design, MDF is an Ideal material.
IF...I changed the end supports to aluminum bars....and they're
3/4" x 3" so that's easy to do with some of these...

8020 T Slot Aluminum Extrusion 15 S 3075 x 48 N - eBay (item 370128452516 end time Mar-30-11 07:18:21 PDT)

They DO make it look somehow "better", but in reality it's
zero gain. I'll eventually try it just to show one...

Then, If the remaining MDF parts...the sides....were water-jetted
from say 3/8" AL plate, there's still no gain as far as the
strength and reliability of the frame. With the existing MDF, it's
as strong and solid as it'll ever need to be. There's no 1hp trim router that
can flex it in any way.

One useful thing I think makes a big difference with MDF structures
is the use of tensioning.

MDF is amazingly flat and good MDF is exceptionally stable. For the
long haul. After making literally 100's of machines from it, I've
seen it firsthand.

One of it's true drawbacks is one that's rarely mentioned. And that's
it's compressibility. But, oddly enough, it can also be a benefit.

Consider one of the major problems in metal machines is that, really,
all the mating sides/edges/parts need to be machined flat. That
can be a real PITA.

Use of tensioning with MDF and it's slight compressibility, causes
a sort of "form-fitting" of parts that aren't exactly perfect. Metal
won't do that. Things bind easier with a fraction of misalignment.

Note I cut pockets that my support bars fit into. That means the support
bar can't move up/down, left/right out of alignment when tensioned
in place. The inner core of MDF is always a little softer and the
form fitting is automatic. Using aluminum plates on the outside
makes the nut unable to press into the MDF. Tensioning together
a very strong and rigid structure.

I've checked and checked into making the sides out of plate metal, but
again, it only adds a lot of cost for no real gain. At least for what it'd
add to the end cost of a machine. Then someone may as well think "bigger
machine"...

I've got some of the aforementioned 8020 that I'd intended to use
some 15mm Hiwin rails for a couple smaller machines. The 8020
isn't flat enough to use without machining it. The 15mm rails will
conform to the very slight bow in it. Binding problems.

There is one little detail I'd love to do, and that'd be have the MDF sides
powder coated. But that needs to be a large order to warrant that expense.
It'd be very cool, though....

I think the A4 is about the right balance of all it needs to be. I'd like
to make some plans for it available, but there are some PITA parts to
make for it. They're as simple as they can be, but their simplicity means
they have to be carefully machined and fitted. Another "Gotcha".

It's tough to win sometimes....


John

[atwooddon]

It's tough to win sometimes....


John

Well John, I don't know about that. ;-) Winning is a matter of perception. If I perceive my machine(s) will do what I expect within their limitations then I consider that 'winning'. IF, they won't do something that I expect outside their limitations, then my expectations are wrong. As a long term 'customer', I have learned to set my expectations at reasonable levels. Doing that, I am usually pleasantly surprised when the tool/machine can go a little beyond the claimed performance levels. Most realistic manufacturers state their performance specs with a buffer level so I kind of expect that from big name companies. For one-off or small business purchases, I pretty much expect the stated performance has no margin or may be slightly overstated.

All this grey hair has made me much mellower than my earlier years. I used to rant and rave at missed expectations, but decided it wasn't worth my time since the end result typically didn't change..... Although along the way, I did discover some products and companies I won't ever buy from again!!! LOL

Don

[microcarve]

It's those "gotcha's" I'm referring to....

There's little chance of winning against those some days....

The latest gotcha is the slide I showed here....

http://www.cnczone.com/forums/899142-post484.html

The things are turning out beautifully!. They work great and aren't too
hard to make...so far....

But they take a "just a bit too much" amount of time to make and
that puts the possibility of selling them at a price where they
may not do as well as they should.

The first pair is half done and even works reasonably well with
drill rod....though better Thomson shafts are the far better choice.

They slide perfectly smooth and should last a very long time.
They're sized for use on small-medium sized moving gantry designs.

But, as nice as they'll end up being, they'll end up costing about
$14 each. That's getting close to the cost of real linear slides.

They do have the advantage of working with less expensive round rails,
but then, lots of people don't like unsupported rails.

They are pretty and will work great, though!

Still trying to decide if they're worth making....


John

[atwooddon]

John, couple questions:

Are you using urethane for the linear slides you are testing?

And, back in this thread somewhere I think you showed a spindle powered by a sewing machine motor. I am interested in how you did that since I really hate the noise my router makes. Would love to be able to machine with just the cutting noise.

thanks, Don