XL 18 and 72 tooth pulleys.
XL 170 Belts.
Spacer width is approximately 38.5mm.

I would ditch the bearing cup idea and just use an flange bearing.
This would require you sizing the bearing holes in the plate drawings to whatever flange bearing you could source.
The bearing cup idea works but it is tedious to machine and the flange bearing would probably work just a well.
Your spacer width will change if you use flange bearings.
Once you have all the parts it will be relatively simple to calculate your specific spacer width.

Regards
Ross

Quick Update
 

While it might seem I have been a bit quiet on my projects lately, in fact I have been CNC'ing away very actively in the background.

A CNC associate has asked me to assist with the commissioning of a surfboard shaping machine.
While the Mechmate build went quite smoothly, this project involved bringing to life a CNC machine that was not designed with the same care as the MM.

The amount of problems with this project was a real eye opener.
Everything went wrong and I do mean everything but through this process it provided the opportunity to refine further what I learnt on the MM build.
The fellow surfer I worked alongside is a great hard working guy and totally committed to understanding his new machine.
The redesign process we had to undertake ranged right from the control box electronics, to upgrading the power supply and cabling, mechanical and motor upgrades on the machine itself.

Even once we had the machine working then it was time to put in a vacuum system to hold the boards.
A laser aligner was next and then adjusting the supports to get the software board models to match the output from the machine itself.
Given the combination of issues and then some new software on top of that, the learning curve was long and steep.

A short thanks to the MM forum people acknowledging the value and power of the shared knowledge in the forum.
A project with that many issues would have either cost a fortune to fix or lay idle as a failed project.
From my perspective it is such a pleasure to share my knowledge with other surfers who genuinely appreciate the precision that CNC machines bring to their designs.

regards
Ross

Hey Ross !!!

Thanks for the drawings, this is my way.

Nice sound with the reductions, you have one accuracy comparative after and before?

Regards.

Hi Ros

I have not fully tested the accuracy.
I need to have a good look at that as some of my circle fits are a bit tight at present.

regards
Ross

Measuring Calipers
 

Hi All

A forum member visited me today for his dose of CNC 101.
He is a competent and talented fellow who makes incredibly accurate miniature building models with his laser cutter.
Horses for courses, so he was looking into the more industrial capability of a full size CNC machine for some of his other ideas.

As a demo project I made a new updated design of a surfboard thickness tool.
A small sheet of 12mm ply made 4 sets for around $2.50 a set.
For those of you without a Mechmate that will be around $25 a set thanks :).

Attachment 13690

Regards
Ross

Video of My Machine Cutting a Prototype
 

Hi All

I got around to editing some video of my machine making the prototype of the measuring calipers posted above.
Very happy with how well my machine is running, so for those of you still building, here is something to look forward to :)

http://www.youtube.com/watch?v=i85uyzjPv5A

Enjoy
Ross

Very nice, Ross.

Powe Supply Example
 

For those of you considering using a switching power supply rather than the recommended torriod and lots of capacitors check out this photo of the insides of a Perreaux power amplifier.

Attachment 13691

Perreaux make magnificent audio equipment, note the similarity to our power supplies that also require smooth rapid busts of power.

Regards
Ross

looks like it has 3 rectifier bridges ... so 1 transformer and 3 separate supply ? but maybe I'm wrong.
P.S.
Well, I remember years ago I built a power amplifier that had 1 toroid transformer and then two separete power supply circuits, one for each channel, it was a "impulse" amplifier type (not continuous) following the Carver concept that can supply hundreds of watts for short periond even if the continuos power was much less.

Sharp eye there !
The amplifier is a 6 channel bridgeable unit.
So I am assuming three different left and right circuits powered by their own rectifier/capacitors.
This reduces/ elimates cross talk I believe.
The price for these is around 10,000 AUD :eek:

Regards
Ross

for 10k AUD, it better sound good!
I prefer building tube amps... at least they weight more ;)

Modeling a Dust Foot
 

I have made a prototype dust foot for an air cooled Chinese spindle.
It has been cut out of MDF and depending on how it fits, the final item will be made of polycarbonate.
The brush will be glued into the rebate and some rare earth magnets will hold the top and bottom pieces of the foot together.
The design is similar to my own dust foot but made as small as possible to allow for the 3D work the air cooled spindle does.

Attachment 13710

Attachment 13711

Attachment 13712

Regards
Ross

Brush
 

Hello Ross,
I live in Toowoomba. I was wondering where are you going to get the Brush material from. I've been looking but have not yet found a supplier. Could you assist.

Thanks Dale

Sure Dale - but that depends on how you feel about being robbed.:)
If your fine with that go to Industrial Brushware at Wacol.

If you find someone who wants to sell small quantities or has some softer bristles, please let ME know.:rolleyes:

Regards
Ross

That is pretty. I do wonder, though, how long your bristles will be, and whether they'll be able to reach the bit?

Should be very close especially around the back!
The bit is 110mm x14mm and the brush is 75mm long.
Any thing that hits the bit it can have.:)

Ross

If you have patience and some time, get a "bottom of the door" threshold skirt and bend it up.
...Or, I have used a soft push broom and weatherstipping to make one up.

My experience thought me that there are no one answer to this. one has to do some trial & error to find the solution.
I had very bad experience with "bottom of the door " brush. From where I'm from, they only come in about 1" (25mm) height & because of this my shoe crash into clamps & other protruding objects around it & causes lost steps & ruin the work-piece. Get something taller, but too tall will get in the way of the spindle... I now use heavy duty transparent door curtain strips for the purpose. mine is ~60mm , If it is 75mm, my bit will chew up the skirt.

Polycarbonate Tip
 

Ken you are soooo right there.

I machined some 12mm polycarbonate for the dust shoe a few days ago.
Halfway through the pieces I thought to try using my DIY droplet cooler unit that shots air and coolant drops on the polycarbonate.

Well THAT works.
Attached is a pic of the off the machine cut (Rinsed with water of course).
No more 12,00 RPM limit as the heat build up and melting is no longer an issue.
This cut used a 2 flute 3mm carbide bit at 20,000 RPM.

A spray bottle would probably work just as well and just require a little more operator input.:)

Attachment 13726

Regards
Ross

Hi Ross,

looks nice, reading about your success with coolant I remembered reading somewhere on a Dutch site tips for a perfect finish straight of the table.

Disclaimer; I can not try / have not tried them yet myself as my machine is not finished.

PMMA /POLYCARBONATE:

First pass:
single flute CCW
100 mm/sec @ 24000 tpm
leave 0,5 mm depth wise ( eg. material 6 mm then this pass 5,5 mm deep )
offset this first pass 0,2 mm from actual line.
with dust suction and without coolant

Final pass:
10 mm/sec @ 24000 tpm ( so feed at 10% of first pass)
0,5 mm deeper then material ( eg. material 6 mm then this pass 6,5 mm deep ).
without dust suction and with coollant ( they recommend distilled water for easy & clean results )

http://s12.postimage.org/lvyd9xvdp/PMMA_1.jpg

http://s11.postimage.org/brsp4k4pv/PMMA_2.jpg

post 900...WOOOT, where can i collect my prize ?!

When it came to brush stock for my dust foot, I contacted a company called Sealeze (www.sealeze.com) and ended up buying some of their Ez-Flex flexible strip brush. It is pricey but exactly what was needed. I just cut a groove around the perimeter of the dust foot and pressed the brush into the groove.

Thanks Jim

Ross

Omg i just read your whole thread, great work! Btw i build my shape bot last month. Almost done.

https://www.youtube.com/watch?v=EQw5...e_gdata_player

Hi Jon

Thanks and enjoy your own personal CNC ride.

Regards
Ross

Z Slide Alternative - No Machining Required
 

Hi All

I was shown this profile yesterday from IVT.
One glance and it was obvious to me that I was looking at a Mechmate Z slide that required no machining and had some serious rigidity as well.
It also has a stainless steel runner for the V grooved bearing.

I will not go into pricing but in comparison to a per meter rate for the USA, you would NEVER machine a Z slide yourself.
Here in Australia we can not buy the raw tool steel for the price.

A tiny modification in the spacing of the spider plate V groove bearing bolts may be required.
The slide is 105mm (measured it at 104mm) in comparison to the stock Mechmate 100mm plate width.
The Spider plate has more than enough width to accommodate this tiny 2mm offset per side.

Attachment 13807

Attachment 13808

Attachment 13809

Regards
Ross

That is a nice piece. I had a lot of time in machining mine for the hardened V groove rails I used on my Z. That would have definitely been a nice alternative.

Looks nice!

3D machining
 

Not something I do very often but thought it was time to run this one through.
It is Red Oak 180x180x19mm tile size.

This is straight off the machine all I did was round over the outside cut edge with some 320 grit.
Machining time was very long done so just to see how good the finish could be.
Wax finished... of course :).

Attachment 14005

Attachment 14006

Ross

wow looks very nice Ross ! How about a close-up ?
Seems you did not sell your MM yet, what about the new 'secret' plans ? On the backburner ?

Hi Fox

Will try for a closer shot tomorrow.
I have been actively studying away just not putting any non Mechmate stuff in the MM Forum.

My plan was always to create some space as it is limited for me, so no new projects until that happens.
I enjoy using my machine so I am in no great hurry to part with it until the right person and the right offer comes along.

Ross

Ross,
What was your finish bit and stepover?

Pete

3mm 2 Flute Carbide Ball Nose
7.5 % Stepover
Approx 45mm/Second
20K RPM

Fox

Attachment 14011

Attachment 14012

Cheers
Ross

Ross, you can be Proud of that finish ! Keeps me going at my build these kind of things, lately I can only make a few hours every week ! Hope my mm will put out such nice finish straight of the machine. How big are these details in real life !?

Thanks Ross for the files
Fox if you put the effort and research Ross has into your build you should get similar results.

How about we let Ross put "non Mechmate stuff in the MM Forum" in this thread so we get a glimpse of where the learning from the MM build has taken him.

Regards
David

I don't thing there has been any photos that have not been allowed by MM builders.

@David, for effort and research I should be more then fine :) Learning a lot from all kinds of angles about CNC and MM in special the past half year, want it finished before my summer holidays.

@Saifl, David is more talking about having the non MM stuff in the future instead of the past. I personally never mind to see derivatives to other stuff in forums, but I think Geralds protection of this forum being strictly MM makes sense in all kinds of different ways, even though sometimes it's a bit cumbersome/counter productive.

Ross could always post a link to a CNC zone thread if he has one/make one, or some dropbox or flickr sets ?

Aluminium Proximity Bracket
 

One of my "do some day jobs" was wire up the proximity sensors.
Done that now but I was never happy with impinging upon the space behind the spider for the Z proximity.

I cut and bent an aluminium bracket to hold the sensor so here are a few pics.

Attachment 14106

Attachment 14107

Attachment 14108

As I have never posted a video of my machine cutting aluminium here is one to ponder on.

http://www.youtube.com/watch?v=iaAz2...LTcB6p4n339KvA

If you are wanting to do it easy then using an air and coolant mister like the one in my thread is the absolute go.
Note in the video you can not see the mist it is so fine.
I got impatient and tried to cut it dry first time, what a mess.
Big black patch burnt into the spoilboard, smoke alarm reminding me all was not going smoothly and some wasted stock.

The sensor will need to trigger at two different heights, one for full travel and a reduced travel setting when the dust foot is being used.
This part is still in development but will probably end up being a small fixed angle with two triggering holes.
The unused hole will be blocked with a magnet for a fast swap over.

Ross

Nice work as usual Ross :D
Good to see you are still working away on your big blue MM. Great work on cutting the ally.

Cheers
Tony.

Hi Tony

Good to hear from you and hope you have had some time to enjoy the perfect weather we are being treated to recently.

Ross

Nice going Ross, what bit, feeds and speeds etc for the ally?