Thread: $15k - Which off the shelf machine?

Originally Posted by Bob Willson

rodm is the father of this CNC division.

saisay, you weren't meant to be telling him how good it is, but how poor it is. The fact that you are now engaged in replacing all the HDPE parts should also be a good guide as to how strongly constructed the machine is (or rather isn't).

Any of the Chinese machines that have had the elcetrics electrics upgraded to Geckos will pi$$ all over the shark.

For what they are (over)charging for the Shark, it is a rip off.

Bob it seems like you have a strange aversion to the Shark and a love affair with Chines machines.
Iam not going to engage in an argument about whether the Shark is overpriced but I have no wish to rubbish the Shark. I am pretty sure I got what I paid for. I would never have received the kind of support I got from CarbaTec, if I had bought my machine from China.
Have you ever taken a Shark apart and looked at the innards? I have.
Tell me which machine can improve on 0.005mm accuracy, please.
The fact that I am replacing all the HDPU parts is partly because of the look, partly because I am a born tinkerer and partly because I am asking more of the machine than what it was designed for. I was reading a post the other day where someone was saying that most members here are struggling to cut aluminium. Well, I am cutting 22mm aluminium on the Shark.
The router bracket was the wrong size for the large router I am using and enlarging the hole was not really that satisfactory, so I decide that, as I am making a new one, I might as well do it in alloy, then I didn't like the look of alloy against the black router support so I make that as well. The gantry, although it is made in HDPU, is also reinforced with heavy alloy U brackets. I re-designed the gantry sides to utilise the size of the table as much as I could, not that there was anything wrong with the old ones, it is just the way I am.
I have not seen adjustable double bearings anywhere, so I did it myself, making them rock solid on the rails. No need for supported rails, the support is already there.
There is no way in the world I would ever be happy with a machine built from MDF or ply and steel does not last long up here.
As I said, once I took the Shark completely to pieces, I was impressed how well it is designed, pity the manufacturer is a cheapskate.
When I decide I need a bigger machine, I will use the Shark to make the parts.
I have yet to hear from anybody who doesn't wish something was different about their machine. No matter which machine you buy, there is always room for improvement.
I have no idea what the difference is between Geckos and stepper motors, hence I cannot have an opinion on that but what I have works for me.
I made inquiries about an Aussie built desktop machine and I am still picking my jaw off the floor over the price.
I do not know what you use your machine for but I am not normally into designing machine parts, I never was a machinist in the first place.
Actually, not much is shown in this forum about what people do with their machines, it is all about problems and what should I buy, where can I get the parts?

So, let's agree to disagree, I like the Shark, you like China.

Today I had a look at a second hand, very well made, full sheet machine with vacuum table.

I just need to find room for it in my shed which I think is possible.

This will work well for me as all I need to do is step back in time and source a computer running windows, load the software, and I will be up and running.

How much?

I'd rather not say at this stage without the sellers permission, but it is within my budget, even allowing for pc and software.

Originally Posted by Jack E

Today I had a look at a second hand, very well made, full sheet machine with vacuum table.

I just need to find room for it in my shed which I think is possible.

This will work well for me as all I need to do is step back in time and source a computer running windows, load the software, and I will be up and running.

Sounds like you found what you wanted, post up some pictures if you decide to go through with the sale, I'd love to see what you got.

You may have already seen pics as it is from a member here.

I won't disclose details until I have pulled the trigger so to speak and we have made a deal

Originally Posted by SAISAY

Tell me which machine can improve on 0.005mm accuracy, please.

Hi SAISAY
In the interests of providing accurate information to the forum readers I consider your claim of 0.005mm to be misguided. Given the Shark runs on Acme threads, direct coupled to the Stepper with no antibacklash bearings the accuracy would be likely in the tenths of a mm. There are other factors such as unsupported linear rails, single screw and a router rather than a spindle that will affect the accuracy of the Shark.
I have assembled and give training on the Shark so the machine is not foreign to me.
To achieve 0.005mm accuracy one would be looking at a heavy cast iron machining centre using very expensive certified diameter cutters. Even with one of these factors such as cutter deflection could produce a greater variance than 0.005mm.

To put the measurement into perspective 0.005mm is 5 microns or 2 ten thousandths of an inch. A human hair is around 7 thou.

I am pleased to hear and impressed that your Shark is cutting 20mm ally plate.

I don't want to be drawn into the Shark verses the Chinese machines but I think it important to give accurate information so readers can make their own minds up.

We do have a projects (well a closed one too) thread but people posting stuff get little or no feedback so eventually stop posting. That is the trouble of too many lurkers and not enough participation.

I really didn't want to start a Shark debate

Some people prefer a turn key set up, I am one of those people.
Having an industrial electrical and electronics background I'm sure I could build my own machine but I don't really want to for various reasons.
My problems may have been solved anyway

Rod, on your point about info, I understand forums are rife with new people asking the same questions but for some reason the cnc forum is difficult to search.
Possibly because people new to cnc don't know the vernacular.

For example, in the last few days I have read many threads and saw a lot of mention about 6040 and 6090, but it didn't click for a while that they were model numbers.

Also, many people don't even consider chinese machines as they have a bad rep, but it seems in the cnc field they can be a viable solution.

Another example, I am currently searching for dust collection solutions to the moving gantry problem on a cnc but am not having much luck.

Originally Posted by Jack E

I really didn't want to start a Shark debate

You didn't


Rod, on your point about info, I understand forums are rife with new people asking the same questions but for some reason the cnc forum is difficult to search.
Possibly because people new to cnc don't know the vernacular.

True but I think you may have missed what I was trying to do which was correct some info. Questions are good and not a problem if they are repeated by others. BTW I also find search difficult.


For example, in the last few days I have read many threads and saw a lot of mention about 6040 and 6090, but it didn't click for a while that they were model numbers.


Also, many people don't even consider chinese machines as they have a bad rep, but it seems in the cnc field they can be a viable solution.

Chinese machines cop a bashing. My workshop is full of Chinese and Taiwanese metalworking and woodworking machines only because that is all I can afford. I recently got a $8k milling machine and this is something I could not afford new from a European source. Almost all power tools including Dewalt come out of China now. It is the buyers that determine the quality and not the factory.
I would not use a 6040 or 6090 without first changing the electronics and wiring. That might sound bad but you cannot source the materials to make one for the price of these machines so they are a good starting point.


Another example, I am currently searching for dust collection solutions to the moving gantry problem on a cnc but am not having much luck.

There are a few solutions on some of the machine builds. My advise would be to go overhead with 100mm hose and a high volume low vacuum dust extractor. House your dust extractor outside the shed otherwise you make the fine particles airborne in the shed and later a cyclone in the system is a good addition.

Enjoy your CNC journey.

..

Hi Rod,

I agree completely with your point on chinese machines, much of my machinery is made in China.
From a cnc newbie point of view, I wrote off the chinese machines simply because they are so much cheaper than others.
What you say about using them as a starting point and upgrading them is in line with what I was saying.
However this isn't apparent to a newbie searching for information

Even though I have possibly sourced a full sheet machine I am also considering a smaller chinese machine to start experimenting with aluminium.

Re the dust extraction, I have in my workshop a 3hp cyclone unit with 150mm ducting, but I probably won't use this on a cnc as it would be a long run.
I also think it would be overkill.
Many years ago I modified a 1hp extractor to work similar to a cyclone so will probably locate that closer to the cnc and use it.

However, is a high volume low velocity (dust collector) necessary?
On a router table I use a vacuum cleaner split into two hoses above and below the table which works well.
A cnc is basically just a router table so shouldn't a vacuum cleaner be okay?

Of course, I have little experience with cnc but that is my initial thought.
From my reading here so far, and as you have said, 100mm seems to be the go.

Regardless of that, my main question about a dust set up is not the system, but how to attach it.

On a full sheet machine the hose needs to travel quite a distance in all directions.
This is the area I was searching for inspiration.

Originally Posted by Jack E

Hi Rod,

I agree completely with your point on chinese machines, much of my machinery is made in China.
From a cnc newbie point of view, I wrote off the chinese machines simply because they are so much cheaper than others.
What you say about using them as a starting point and upgrading them is in line with what I was saying.
However this isn't apparent to a newbie searching for information

I have said this on a couple of threads including a review of a 3040 I sourced from China. Get's back to having a poor search engine on this site.


Even though I have possibly sourced a full sheet machine I am also considering a smaller chinese machine to start experimenting with aluminium.

You should be able to cut ally on your big machine. Golden rule is you can make a small part on a big machine but not a big part on a small machine. Having said that far be it from me to discourage another machine purchase.


Re the dust extraction, I have in my workshop a 3hp cyclone unit with 150mm ducting, but I probably won't use this on a cnc as it would be a long run.
I also think it would be overkill.
Many years ago I modified a 1hp extractor to work similar to a cyclone so will probably locate that closer to the cnc and use it.

However, is a high volume low velocity (dust collector) necessary?
IMHO yes. Hold a LVHV vacuum about 25mm from you hand and you feel nothing.

On a router table I use a vacuum cleaner split into two hoses above and below the table which works well.
The sawdust on a router table is trapped between the timber you are machining and the vacuum chamber of the router table. Also a CNC machine works a lot faster than you can machine timber by hand.

A cnc is basically just a router table so shouldn't a vacuum cleaner be okay?

It does the same job but it is different. A router table the spindle (router) is stationary while a CNC machine it is suspended upside down and moves over a big area. That is obvious of course but to get it working the same you need a dust shoe and a vacuum hose that is able to travel with the spindle. The usual way to do this is to make a swiveling arm fixed to the side of the machine and as high as you can practically get it in your workshop. Attach the 100mm hose to the arm and it hangs the rest of the way to the spindle. The centre point of this arm should be the centre of your table. You seem to have a good handle on things already so I'll stop here.

I think I remember the fellow that makes moulds and science fiction costumes has a good example - can somebody who has a better memory than me point to his thread please. My apology for forgetting his name.

..

One final thing about the Shark. I'm not really knocking it, just saying that for the money you can do much better. If the Shark suits your needs then be happy.

This is the machine that is sold in USA for almost half the price that Carbatec sells it here in Oz. We do get a ($300) router thrown in with our version though.

There's a fellow in Perth, W.A. with two Tekcel K series cnc 8x4 ft routers for sale.
They're Aussie-built, and would be about the year 2000 vintage.
He had them on fleabay for a while, at $9k (each), and now has them listed in a WA machinery dealer website.
I think both are a 2-head machine, but you could pull one head off, and easily reset the Tekmove drive program to tell it there's only 1 head.
The spindle is a 3 hp Perske.
To me, that is a bargain for a good machine.

Our own router here is much older & was retrofitted with Tekcel K series electronics in 2001.
It has its issues, but that's to do with the age of the wires & things like that-not the Tekcel aspect.

They're in a woodwork shop that's been running for years-and the shop has 3 routers. The owner is scaling back to what he can handle with just himself & no other staff, leading toward retirement, I think.

Personally, I'd be flying over for a look, before flying to China- I know there's the freight issue from WA to the rest of Oz, but the seller does speak English, and there are Tekcel service agents in Sydney & Brisbane.

Rod, that all makes sense, cheers.
As for cutting ally on the big machine, I am a bit OCD and don't like to mix metal work with wood work.
If I had a smaller machine it would go on castors and be used in the carport, which is where I do my metalwork.
Plus, the machine I am looking at has an mdf table which wouldn't like having lubricants anywhere near it.
Again, this is all new to me and cutting ally on it may be feasible

As for the fellow making science fiction costumes, my brother is mad for that stuff, I'll have to search around and see what is possible.

Stewey, thanks for the tip, I found those on machines4u.
If the current machine I am looking at doesn't work out I will consider one of those.