Ries & Irfan, it could simply have been a case of a dirty connector pin on a particular cable and that could be why replacing the cable fixed it. I tend to agree that measuring "resistance" is going to be a tricky subject if we are just going to hold probes against pins.

Hi Guys

I agree that measurement error coupled with instrument error and a typical lack of calibration means we are likely to see some vastly different readings. The discussion did make me think more fully about the subject though and I now have some gotchas to watch out for.

Regards
Ross

All, when I was perplexed why my machine was missing steps,, I found out that a friend of mine had the same problem on his plasma machine, and in both case - it was the ready made parallel port cable problem.

may be we should put this matter to rest now here.

@Mike, may be you can move the couple of posts over to a suitable place?
I feel we hijacked Ross this thread now, that wasn't our intention..

Follow Up on USB Repeater Cables
 

Post 97 and 98 discussed USB repeater cables. I have now done a few tests and can confirm that they pass a signal very well over long runs of USB cable/s.

Anyone who is passing data over longish runs on USB be it control to a smoothstepper or images back from a webcam might consider this as a very cheap insurance policy to protect the quality of the signal.

Acknowledgement to Besser for his suggestion.

Regards
Ross

USB over Ethernet Follow Up
 

A further note - I have found that USB over Cat5/6 adapters are now selling out of China for around 12 AUD. These will give a 150m max cable run over Ethernet cable and do not require external power. These adapters are now on a price par with a 5m USB extender cable but allow the freely available, cheap and pre-wired Ethernet cables to be used.

Looks like ethernet cable might find it's way into the Mechmate cable chains after all.

Attachment 8843

Regards
Ross

Ross: Wish I had found these earlier!:) Thanks for doing the research. I may just go back and rewire!

Joe

Bulk Order or Local Supply
 

Thanks for the updated into, where do we get the adapter or are we looking at a bulk order?

Hi Besser

An Ebay search "USB Cat5" will lead to a few different international sellers.

Regards
Ross

How about an update Ross???

Cheers
Tony.

Hi Tony and Others

That would require some work being done !!

I have progressively knocked over other commitments both social and work since my recent return from holidays and hope to have another go at the machine after Easter.
As I wander past the components they are just calling out to be assembled.

Regards
Ross

Painting - Lower Table
 

Hi All

I have been procrastinating about paint and when to paint.
Decided to paint the lower table first but snagged on finding what I considered to be a good colour in the hammer tone finish paints.

As usual tried mixing some paint of my own using a metalic blue and a black epoxy paint.
It did not work well as the silicone in the hammer finish seems to prevent proper mixing of the black epoxy.

After much searching I found a refinish supplier paint shop who made up a paint I liked from a silver hammer finish base and a blue - red tinter.
Tuned out a nice colour and was very easy to spray with a HVLP gun at 50 PSI thinned with 10-20 percent automotive thinners.

Attached is a pic of the table legs in their new paint. Everything had a full coast of grey primer before the top coat of hammer finish.
The X beams and the Y Cross Bearers are still outside waiting for a second coat but are the same shiny colour.

Attachment 9219

Finally tidied up my welding on the ladder frames for the table base by grinding, priming, filling with acrylic filler and then priming them again.
They are now presentable enough to get their own coat of paint.

Attachment 9220

Regards
Ross

Hey!!

I wondered how long it was going to be before we had an update :D Looking very good Ross, and the hammertone colour sounds very interesting.

Tony - Finally !

For reference I used two liters of paint to do one topcoat on the legs, the X beams and the Y cross bearers.
That leaves the ladder frames to do in two coats and another coat for the other components.

Looks like 5-6 liters of topcoat will do the whole job incl. the gantry and Y car and a few touch ups - way more than I originally guessed.

Ross

Ross, That is nice paint job. Also a lot of paint, I only bought 2 liters of top coat & still have enough balance for a 3rd coat... no solvent too...

Hi Ken

Yes it is a lot of paint but the hammer finish effect changes with the volume of paint wet out.
When spray applied, you spray for your desired level of hammer toning and that is how much paint you use.

It is a pretty thick coat and needs to harden up before it is worked with.
I leave it to "cook" in the sun for a day or so but it is still soft eniough to mark for a while so a touchup will be required here and there.

I have followed your build as you know, and as we both have selected this finish it just has to be the the best one, haha.

Regards
Ross

I mentioned the volume so that other builder won't have to stock up excessive paint ;)

Careful with cooking the paint, contrary to common believes, paint don't really like heated up under the sun too much. Here, metal can heat up to easily 85C & as high as 100C, which is demaging to the paint. Years ago when I was a lot younger, I left one of my paint job under the sun for a day & I got bubblle effect on it, then I found out the paint actually boiled...

For my build, I gave at least 16 hours to cure before the next coat. Over 3 day after the final coat before I did any work on it. but I recon you need more then that.

Hi Ken

I found a hole in the tin maybe that's where the paint went !!
Only kidding again there Ken - used 4 liters so far and I'm pretty sure it all went on to the steel excepting for a little over spray.

As I am thinning with automotive thinners it dries a fair bit quicker than the same product thinned with turps.
Part of the explanation for the paint use is I have to spray it thickly to get it to wet out and hence form the hammer finish.
The benefit here is it dries more quickly and it is easier to get a run free finish than thinning with turps.
If you thin with turps you will get a better gloss but a slower drying time.

I got a bargain on the paint and for 2 liters paid less than 3/4 of the normal shelf price for 1 liter, so using a bit more paint has not added any significant extra expense.

Thanks for the tip on the sun, I will move it into the garage once it is cured enough to not mark the paint.
My progress so far ... lots of blue as per the Mechmate manifesto.

Attachment 9222

Regards
Ross

Looking good Ross!

Thanks Heath

Now to leave it for a few days to cure before assembling it.

Regards
Ross

Hi Ross,

Looks impressive!! all that painted steel. What did you use to prep all your steel and what was the process? going to be looking to prime ours up sometime fairly soon, we have a fair amount of prep to do with regards to surface rust mainly on the main X beams and Y support channels, so interested to hear what your process was.

We might need to have another little get togetherat some stage once you have yours all together again, would be nice too see it nearing completion. Plus I have your countersink bit too return too.:)

Cheers
Tony

Hi Tony

Just finished stacking the stuff inside my garage.

The steel was degreased and vigorously wet scrubbed with a plastic scouring pad. Destroyed quite a few in the process.
Any thing else that needed attention was just given a (very) rough sand, blown off with some air and then cleaned down with thinners.
After that, it is was spray undercoated with a grey rust guard primer (White Knight) then topcoated with the hammer finish.

I tried tapping some M6 holes on the motor plates and all was going well by hand.
Got greedy and then broke a bottom tap off just running one hole through with the battery drill !!
A crash, bash and hammer later had the broken bit out and managed to still put a new thread down the hole. Today was my lucky day it seems.

Cheers on the countersink Tony, it's nearly time to catch up again.

Regards
Ross

While the Paint Hardens
 

Finished tapping the M6 threads in the motor plates this evening.
After finishing the motor plate taps I was thinking about how to keep the tap at 90 degrees and the number of taps in the X beams and gantry.
Made two M6 and M8 guides out of 20x20mm stock to keep me straight to start off with.
The pic is a little hard to see but it is a hole in the stock that "just" fits the tap.

Attachment 9241

Also made up the 20x6mm clamp strips for the gantry.
A question for the knowledgeable, one gantry tube is 2mm longer than the other one.
Can I get away with this variation or should I attempt to cut the extra 2mm off the long tube?

Thanks in advance
Ross

Attachment 9242

USB over Ethernet Follow Up
 

I have continued to test a webcam over the USB baluns mentioned in post 126 over a range of cable runs and they reliably run it over 10 - 15m.
The baluns will make the connection to the webcam initially at 20 and 30 meters but will not maintain it.
Not great, but better than the 5m standard cable run for a USB cable on its own.

Ross

Hi Ross,

I would think that the Gantry beams would have to be exactly the same size otherwise your gantry will end up out of square before you even start.

Cheers
Tony.

Ross,
Your question on gantry tube length is a ligit concern, but not a reasonable one.
They are part of an assembly that you must assemble (weld) square.
One simple method is to cut both of those tube together at the same time, held be some sort of clamping, assuring an exactly same length without measuring anything.
BUT YES, they MUST be the same length. Read some more about how to weld & assemble the gantry here and here.

Best of luck. Amicalement, Robert ;)

Hi Robert

I should know to never even think about cutting a corner, so I hear both you and Tony loud and clear on this one.

Thanks for the advice.

Regards
Ross

Assembly Time for the Bolt Together Base
 

A milestone for my project today as I assembled the table base this evening.
Time to also acknowledge the many others on the forum who have contributed their photos and ideas for me to use in my own build. Thank you.

Here are the photos of my table base going together.
Attachment 9244 Attachment 9245
Attachment 9247 Attachment 9246

Regards
Ross

Very nice!

Looks good Ross! The color has some sparkle to it?

What size table are you building? 4'x4'?

Hi Travis

Yes the paint has a metalic in it.
The table size is 2500 x 1300.

Ross

Y Car Test Fit
 

Popped together the Y Car for a test fit this evening and was very impressed with both the quality of the laser cutters work and Gerald's DXF files.
It literally snapped into place excepting the the last corner that took a little hammer to convince the tab to go into place.
As per other reports it holds itself together even before it has seen a weld to it.
Attachment 9252 Attachment 9253
Attachment 9254

Springs - searched high and low for a spring that was near the plan spec and came up blank.
In the end found a specialist spring manufacturer in one of our industrial estates who could make myself, Skippy and Aus MadDog a set each.
The proprietor was happy to see the Mechmate plan M3 10 100 K B as his guide.
He said he could get the 12 kg force at 128mm as per the spec from his computer controlled spring making machine.

Regards
Ross

Hi Ross what are you doing with my tablesaw. I think we have the exact same model. Does yours also have the sliding table on the left side ?

Hi Kobus

Have you checked in your shed to see if it is still there !!
It is quite old now and still perfectly functional, but I remember when I bought it the sliding table was an option (unfortunately I did not buy it at the time).
The thing that drew me to it was the very good quality fence it had for the price.

I have worn out the original motor and replaced it with a more powerful one the second time around.
It is pretty much a one owner dog if you know what I mean.
I have seen very tough men step back when it starts and cabinet makers shudder in horror at the lack of guarding.
The original riving knife setup was an accident waiting to happen so it came off and never went back on.

Hope yours has also been a faithful servant.

Regards
Ross

I had no problems so far...have changed the v-belt a while ago, but still on the same 2.2 kW motor.

I have not connected my sliding table at the moment due to space constraint, but I am planning to extend my w/shop in November / December adding another 2 meters in the width....then I will have 12 x 5 meter space. At the same time put in proper windows and a ceiling.

Welding the Y Car
 

Today welded the Y car first with the TIG then later with the stick welder.
The outcome was not what you would call overly pretty but it was straight.

Once I put the two central welds on the plates that hold the Z slide it they kicked out of square.
In order to remedy that I cut 4 short pieces of M10 threaded rod and set them to were they should have been top and bottom with some nuts and washers (210 mm to the outside of each plate from memory).
It worked well and when I undid the rods, the plates remained square.... thankfully !

I ground off what was some horrible looking mounds of TIG welding and the pics below are the outcome.

Regards
Ross

Gantry Welding
 

Set the table level with a water level to a mm or so and then clamped the gantry tubes to the tables as per the Aus Maddog and Skippy setup.

Pleased to report the distortion was absolutely nothing and the gantry sits on the table with no twist at all.
The welding is strong and has good penetration but is going to need a tidy up with the grinder to make it look presentable.

Been doing my homework on the rail cutting and grinding options - no clear winner at this stage on my method.

Regards
Ross

Well Done Ross!!

Your gantry looks just like ours :D
three gantrys now done using this same method and worked a treat for all, certainly a nice easy setup and way to do it, and the end result ends up working out spot on with no distortion what so ever, certainly helps having everything bolted and clamped.

Let us know when you are ready to do your rail cutting and we can arrange the use of our skate parts if required. Just not sure what your thinking yet :eek: should be getting onto cutting and grinding ours soon, I think I have put it off for long enough now!!

Cheers
Tony.

Ross in the US we call it Bondo. I used it to smooth out some of my welds. Use a flexible rubber hose to spread it out in corners. This is much faster than grinding and leaves the weld as strong as it can be. :D This should make Gerald happy ............ he hates to see welds ground. :p

So you should never grind welds? I was told long ago that the only thing different from a bad welder to a good welder is a good grinder. :)