Thanks for the info here.. I am looking to build a similar machine with a 4ft x 4ft working space...

 

If you are going to buy from China, don't use this guy, linearmotionbearings2008

 

Hi,

any news ? I am quite curious because I am going to start building my OX soon. I guess I shouldn't have to worry to much because I will keep it 700 mm wide, but that would be interesting to see the evolution on your side.

Cheers

 

It would seem that videos on youtube, help you get your money back, well half of it, thats what i asked for

 

So an OX is a really poor choice for a CNC router to build guitars?
I am looking to build a machine to build guitars and that is why I am here...

 

Don't be so sure You can use the bottom motor bolts.

 

You are correct, its nowhere near capable

 

Why do you say it isn't? You can cut aluminum with it, why not hard wood?

 

Its not strong enough or accurate enough for aluminium, as for cutting wood, it can cut it but not quite the same every time, its only take a tooth to jump, and it does.

Also the z axis and the short axis is way too week , when you drill holes you can see the z axis tilting backwards making elongated holes, i saw this in some of the parts made by robocutters.

 

What feedrate/spindle speed do you use? What type of wood and aluminium did you use?

 

woods, mahogany walnut ash and maple, feed rates varied 1200mm /m for cleaning up edges and 50mm/m drilling holes i can't remember why they were for cutting out pockets

 

Thanks for sharing. Can it be done on both side?

 

I am only cutting at 1mm depth for each pass and about the same for the drilling

 

I'm sorry to say, but my OX (1500 x 1000) is cutting within 0.01mm tolerances in all kinds of woods (MDF, Padauk, Rubber Wood, Plywood, etc.) and I have non of the issues you describe. I can drill holes with speeds of 300mm/min without any deflection of the X or Z axis. Feed speeds for cutting up to 3000mm/min with dead on results.

Could it be you made mistakes in the assembly you're not aware off? Maybe not enough fine-tuning of the hardware to remove all possible slack in wheels etc.?

I suggest you run through the whole assembly and check everything on play or slack. When all is OK, try to use the double belt solution to achieve higher accuracy and repeatability. Use power glue to glue the lower belts into the profiles (works excellent with me). Use software that has an option to correct possible backlash (Mach3 has it, I believe also Planet CNC software offers that option).

But above all, don't expect an OX (hobby machine) to perform like an $20K production CNC.

This is what my OX (the Buffalo) did last week, check the speeds on MDF.

 

Hi Prauk,
just a hint: in the vid your cutting speed does look much to slow... cutting mdf is basically cutting up dust back into its original form. So that should be done with as much speed your machine handles - in order not to burn your bit in the long-run.
I´d rather go 5-6mm deep at a time ( if your gantry/motor combo doesn`t alow deeper) goin full speed than going slow in one cut.
This winter my buddy did my wing plugs for a mould i was making, on his big cnc used a whooping 9500mm/min and 6mm deep cut using a 10mm two flute for the roughing and later on he used 8500 for the finishing cuts ( 8mm ballnose).

 

He is just crazy Recommended cut specs from Gwizard for mdf would look like that:

Rough cut:
1/4" 2 flutes Carbide endmill
4mm cut depth
RPM: 19874
Feedrate: 10000mm/min

Finish cut:
1/4" 2 flutes Carbide endmill
4mm cut depth
RPM: 17887
Feedrate: 3286.6mm/minmm/min

 

Of course I can go faster and deeper, which I will do next cutting. But the issue here is that an OX is not the same as your buddy's big commercial CNC. My bit is still in excellent condition, sharp, not burned and the cutting came out clean.

You know what? Show me a video of your OX doing those speeds cutting MDF and I will follow!

 

Edited a typo above:
of course 9,5/ m min not 95 m/min


Hi,
didn`t try to offend you.
I do not own an ox, the machine i use you see in my avatar. It is tiny and slow ( 1600 mm max), but very strong and precise.. build for milling aluminum.
Still i went 1500mm on a 3mm ball nose bit milling a plane hatch in 3 (2,5)D with it. Roughing was 1500 on a 3mm straight bit. I cannot go faster so i have to use small siced bits. and had to recuce rpm to aprox 15000 if i remember corectly.

My buddies machine is still far away from beeing comercial though. But its strong and uses a 2,2kw hf spindle..
Its just that MDF has different densities through its thickness.
While beeing slightly denser on its outside , going towards the center ist just lightly compressed dust.
So the usual taktic is to plunge reasonably fast/ slow through the Surface but cut fast after that. Using slow rpm ( relative) .

A direct recomodation from a german forum: 6mm two flute, 10000 rpm going 6 m/min , z acording to your machine between 3-10 mm.

This vid shows a comercial availible machine, but it is build for the hobbyist, look closely how it is build , it is not the strongest:


You may try or not, it was just a hint.

DDDman: your specs arn`t so much different, are they? 19500 rpm at 10000mm , diam of your millbit depending on your motor

greets

flo

 

There is a bit of a difference between cutting out the letters CNC and doing a rose window, with lots of tiny corners and small circles to cut. If I do cutting on 18mm plywood (just some straight stuff and larger arcs) I go for 3000mm/min and 1/2 the diameter of the bit DOC. Works excellent and I get what I want. Of course I could go to 5000 mm/min and full DOC at once, but for now I'm not sure if the results will be as near perfect.

What good will it do to go super fast and deep with a higher risk of breaking your bits or even more? I see it this way;

The Buffalo can do precision work for me in a relative short time and with little to no effort of myself in it. If I would have to do these things by hand, it will take me considerably more time, effort and sweat (I hate sweating!) to achieve the same or even less. So why this rush? It's a hobby machine, you know.

If I would wanna go commercial with CNC, I will buy or build a commercial grade CNC, stiff as a 2 days old corps in the morgue and fast as a Lamborghini on steroids. For a commercial CNC operation I would not even look at all the hobby machines around. So why would anybody expect highly professional super accurate and fast results from a hobby machine, not designed or intended to give those results? Beats me.

 

Florian you need to read from the beginning of the post. This post is about solving the problem of setting up the ox so it can cut hardwood into guitar body. If you have a belt drive cnc or an ox that can cut this fast please share how you did it.

 

@John foale, how big is a guitar body at its maximum? W x L x H?

 

Guitar bodies are around 1.5-1.75" thick and most will fit within a 14" x 20" block such as my Bass VI,
which is a large body for a guitar.
Necks can be as long as 33 inches for a bass guitar.
The wood used varies but neck are usually from maple or mahogany.
I need good quality cuts and can't sit watching a machine for 8 hours cutting at a time due to health (mental and physical).
Please don't be offended, I am not asking for a $20k production machine, was asking if an OX would be a good choice for making guitars, like the OP.
I am finding that most people who have one tell me it is not.
Need a machine I can build to make guitars and other projects, not interested in a MDF/kludged/weak machine
and it seems a few other people here feel the same.
Can't afford to drop $5k or more into one but I can do under $3k.
The F117 and Steve's linear rail machines seem to be more what I need and I like the v-rail/rack and pinion system the most.
Frankly, I need a machine that makes me feel like you do about your OX but for my uses the OX isn't right...

 

Well, maybe I see it wrong, but what if you change your machine into one with a shorter gantry, more like the big OX? Fortify the gantry with bolts (or use the 3D printed profile connectors I used and which are doing extremely well), use double belts and put the whole machine on a solid box table. You'll probably than have tackled most, if not all, of your problems and can start cutting.

If you're wanna go fast (Lamborghini) you'll have to pay Lamborghini prices. You can go fast with a Ford Cosworth, but you'll need to do some work on it yourself and be a bit more careful while you go fast, but it is cheaper than a Lambo.

Wait a minute, are you the OP or again someone else?

 

Not the OP, just an obnoxious yet interested party.
I hate Lambos, give me an old Model A roadster with a flathead in it or a Torino fastback with a stroked 460
and that Eyetalian money pit will eat my smoke.
I prefer the cheaper yet far better built American stuff.
I need a WORKING machine in case I want to run the thing for more than a few hours a day and like
old American designs I prefer simpler, stronger, and heavier.

Looking at building a F-117 machine: 5010 with open rails, rack and pinions and belt drives.
Should be much stiffer and we all know that stiffer is ALWAYS better.
See the Stiff cymbal slogan....
Working on a 1500mm x 1500mm F117 design, hope it can come together.

 

Ask advice of him about the size before you get yourself into a disappointment.

 

I am working on some things for him on the F117 design and am in communication with him a lot lately.
Seems it is hard to keep the cost below $5k on a machine 4'x4' or larger if one uses extrusions and good hardware!
A dollar doesn't go very far anymore.....