G'day from oz
 

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!

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.

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).

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

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. :D

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 :)

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

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

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.