G'day from oz

[edgey]

G'day,

I have been reading so much on this site! Fantastic info.

Still in the planning stages and have a couple of questions.

Could I use hollow pin chain bolted to rails as rack and sprocket as pinion?
The reason I ask is this is whats holding me up. I can purchase rack and pinion (M1.5) for $68 a meter plus postage and pinion or hollow pin for $26 a meter and I need

I saw that great red beast that used chains but hie set up isn't the same.

Also could I use skate bearings, angle and rhs to build the X and Y acis?
I only have a shed 3.5 X 3.5 and plan to build my mechmate to 2.8 X 1.6 so I need the mechmate to be usable as a bench, I have plans to place another sheet of MDF over when used as bench.

I have attached a bmp image I just whipped up as a visual.

Thanks again for sharing the wealth of info!

[Regnar]

I dont think your bearing plan will work out that great. C channels are somewhat straight but not nearly enough for a bearing surface. I think it would also be difficult to align 24 bearing per a axis.

If you count your time as money the V bearings will end up being a lot cheaper and a lot less frustration in the end.


You should have a look at the plans. I would recommend sticking to them as much as possible to save time and frustration. Everyone here is pretty much and expert on how to build one of these machines. If I were you I would get in contact with a few of the Aussie builders here and ask about their sources. They might have a line to a less costly rack and pinion and if you ask real nice they might even show off their machine to you.

Welcome to the Forum and good luck with your build.

[edgey]

G'day Russell,

Thanks for the reply. Very good points.

Oh and that is a good price for rack and pinion (from what i've seen and read) I actually got the details from a user on this site, they pointed me to linearbearings.com.au.

I was just curios if anyone had used chain like this.

Ok so I'll go rack, M1.5 is ok from what I've read.


I think the mechmate is a fantastic design, my only issue is the X support sit above the support board, could I raise the y axis like so (see attached).

[Jayson]

Hi Edgey,


I agree with Regnar on the rails, as designed they are elegant and work well. I had fooled with a lot of designs before building the Mechmate and I must say that if you build it as designed you can't go wrong.
Having said that, I did not use the full height C channel on my machine, I raised the Y rails a bit to compensate. If you do away with the C channel all together and raise the Y axis high enough to compensate I believe you will loose far too much rigidity in the design. If I were you I would look at having the open end of the machine located in such a position that you can still use it as a bench if need be, but having said that it will always be covered in stuff when you actually want to use the machine. Mine is, and my shed is 6 x 12 meters...

Regards,

Jayson

[edgey]

Hay Jayson,

Thanks for the reply.

After thinking about your points. I realize that all I need to do is build a table top which fits over the mechmate and can be risen when I need the machine. Thanks! I don't know why i never considered "up" as an option.

I to have the horizontal surface syndrome, any horizontal surface Must be completely covered at all times.

6m X 12m shed green with envy! I'd probably get lost in a shed that size.

[edgey]

Can anyone tell me if M1.5 rack 22 tooth pinion will work. I did search form M1.5 but found no matches. Also are 640oz nema 34 good enough for direct drive or should I order pulleys and belts to build reduction drive of 3:1?
I have the steel ordered and will arrive on Monday. It's really going to happen! Finally

[Regnar]

http://mechmate.com/forums/showthread.php?t=1299

http://mechmate.com/forums/showthread.php?t=1114

[edgey]

Ok, I have been on a bit of a spending spree!

Purchased 3 X nema 34 870 oz steppers (come with cheap driver and power supply) $350 AUD
4 X UIM24004 $242 AUD
16 X v groove bearings $114 AUD
12 X sprocket $92 AUD
3 X 2m chain to match above sprockets $30 AUD

I'm going down the chain drive model, like that nice red beast. http://www.mechmate.com/forums/showthread.php?t=2790

The reason why is I'm a newbie to all this and will only be cutting tops for arcade machines and some other bits and pieces in the beginning and the price ($450 v's $130). I have most of the steel from previous constructions and set myself a $2000 budget for the rest. From what I saw and read the chain drive system will cover my needs and I can always change to rack and pinion down the track.

I also purchased a 40amp plasma cutter and plan to attempt to cut my own parts, anyone done this? The reason why I'm trying this is the cutter was $50 less than the kit and i can have many attempts. This is probably a silly idea and i'll end up buying the kits but I'll give it a go.

Once the cutter arrives ill be cutting and welding the X axis.