After seeing the Blu tack on that lead nut I'm upgrading you to an honorary 100% Yorkshire man ..:toot:
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That attempt was complete rubbish. The main weakness was the gantry which as a single lightweight beam would twist under minimal load. I soon upgraded that to two parallel pieces of the same stock which gave me something capable of cutting out thin MDF and plywood pieces at low feed rates.
My current beast is a steel framed machine with nothing of the original one left except the cheap Chinese breakout board and the computer running LnuxCNC. I'll put up a video of it doing something when I have time to make it do something.
Kit
I have included a link to the ball screws and linear rails I bought hope it helps you guide me
https://www.ebay.co.uk/itm/142502702416
Albert
Hi jazzcnc as i said before it my 65th birthday in a couple of weeks so I will have more cash available do you think £200 to 300 will be enough to build the X,y and z axis withe the bits I already have.
Albert
Albert,
I'm using similar SBR20 rails for my long axis (X on my machine) rails and SBR16 on the gantry. I've been happy with them so far. The accuracy of your machine is going to depend largely on how straight all the rails are. Then it's down to to how rigid everything is and how well you can align the beast once it's built. Keep in mind how you are going to do that during the design phase.
The 1000mm rails are going to allow you a maximum of around 800mm travel if you allow about 200mm for the gantry feet. The ballscrew might be the limiting factor there as the maximum possible travel on the screw will be the length of the actual threaded part minus the length of the ballnut. If you want to keep the length of the overall machine down then you will have to drive it with a belt and pulleys.
NOTE: If you run the ballnut off the screw all the balls fall out. You wouldn't be the first person to get caught out by that one. If you need to run it off to turn it round it can be done quite easily though.
650mm for the gantry mounted rails and ballscrew will get you less than 500mm travel and depends either on the ballscrew and nut as described above or the width of the Z axis assembly (mine is 160mm wide which is a tight fit for all the bits but is a standard size for aluminium bar stock) but with a single screw on the long axis you cannot expect to drive too wide a gantry anyway.
If you really are tight for space then I think you could keep the machine in a footprint no larger than the length of the rails/ballscrews using the parts you have bought but it would be easier not to and you will lose some of the available travel, especially on the long axis. You are clearly restricted by the sizes of the aluminium profile you have available which is going to affect the decisions made. This doesn't mean you cannot build a machine capable of useful work out of what you have but some compromises will be required. Based on what you've said, the construction of such a machine will have served it's purpose anyway. Once you have proved your own ability to make a machine that actually works you can then decide whether to commit the funds to doing what almost everyone else does. make a bigger one!
Kit
Hi would it be better if I built the sides from 10mm or 15mm aluminium and how wide would it have to be.
I could use the profile for bracing across the bed.
As I can not see how to attach the rails to the profile as the hole spacing is 30mm and the profile is 40mm
Albert
Having a single screw driving the long axis adds complication to the base design by requiring a moving beam underneath the machine bed. This is not something I have any personal experience of. Dean (JAZZCNC) has built a lot of machines like this and there are pictures of their internals on the forum somewhere. The design requirements for this will affect how you make the sides/base of the machine and what from.
Kit
I've just done a Google search on MYCNCUK images and found a build thread from a few years back for a design which might be on the right track.
http://www.mycncuk.com/threads/8206-...Axis+CNC+Build
I've snaffled one specific image which might give you some ideas.
Attachment 28663
Hi just been cleaning out the shed and found something that might be ok to use.
It is an igus slide made in Germany
It's dimensions are as follows
Overall length 560mm width 130mm.
Carriage is 130mm by 130mm maximum travel is 330mm.
20mm guide rails 18mm ball screw
Trying to add some pictures
Albert