New CNC Mill on the horizon

[fvfdrums]

Routercnc, thanks for the link I will keep an eye out for something that fits the build. Did you find them to be a good seller? How long did they take to arrive?

After sleeping on it I am 100% behind profile rails so am going to hunt some down.

I will get the design outlay up over the next few days and let the critics at it!

[JAZZCNC]

Many moons ago I bought a class 1 ballscrew from the same guy routercnc suggested and was very happy with it, still are.! Thou it did need a strip down and clean to be fair so be prepared that you may have to get slightly dirty to get best from a used components.
Still it's a good cheaper way to have profiled rails and worth the effort and risk. Even if there's a bit of play or slop then it's not difficult to replace balls in both bearings or ballscrews so they can be brought back to life or certainly far better operation.

If I remember correct they didn't take long to come roughly about 2-3wks and was packaged ok.

[fvfdrums]

Thanks for that Jazz,

I was looking at the prices on there and to be honest by the time I have added up the cost of shipping the lengths I am looking at and added the chance of VAT on top its looks like I could buy the same from Zapp for about £25 more but new (thats based on what they have on their eBay store at the moment) probably better to go new I would have thought.

I am assuming 4 blocks on the z axis is a must for a machine like this? This was the original plan but i thought i better check.

[JAZZCNC]

check your PMs

[Jonathan]

I was looking at the prices on there and to be honest by the time I have added up the cost of shipping the lengths I am looking at and added the chance of VAT on top its looks like I could buy the same from Zapp for about £25 more but new (thats based on what they have on their eBay store at the moment) probably better to go new I would have thought.

I am assuming 4 blocks on the z axis is a must for a machine like this? This was the original plan but i thought i better check.

Definitely 4 blocks. The problem is you're just looking at buyitnow listing, which are obviously going to be more expensive than waiting and bidding. Via bidding and negotiation my friend and I have got the following:

Hiwin: New, Two rails and 4 blocks, 15mm*640, £80
Hiwin: New, Two 15*760mm Two 15*1150mm, 10 blocks, £360

THK: New, Two rails and 4 blocks, 25mm*760mm, £100
THK: Used, Two rails and 4 blocks, 25mm*300mm, £80

...etc, you just have to be patient and I need to stop buying them all!

All of those prices are significantly less than the eBay listing linked to in post #7... than one isn't a good deal.

I still want to get two 2120mm rails for my X-axis, but ones that long don't come up very often at all and postage is of course very expensive.

[JAZZCNC]

Hiwin: New, Two rails and 4 blocks, 15mm*640, £80
Hiwin: New, Two 15*760mmw Two 15*1150mm, 10 blocks, £360

Probably Stolen goods. . Lol

[routercnc]

I found them to be a good seller. About 3 weeks to arrive and reasonably packaged in a thick cardboard board with lots of bubble wrap. Would buy again if building another machine (!). My parts were clean and ready to use.

For info I see alot of machines using supported rail on the Z axis and whilst there is nothing wrong with that I would recommend new builders (or upgraders) to have a look at these used profile rails. Putting aside all the advantages of profile rail, their compact size makes for a neat installation in an area of the machine that benefits from compactness. And these short lengths (typically 300mm in a 15mm width) make it good value at about £80 all in.

I know what you are saying about the longer lengths. For my X axis (1300mm) I went with new supported rail from linearmotionbearings2008 (ebay).

Since the Z axis always has an unavoidable overhang I would personally go for 4 blocks.

[fvfdrums]

Ok I'm going with profile rails on all x,y & z 4 blocks on each rail.

My thoughts are going towards a low level gantry eg minimum deflection in relation to the x axis with the adjustability of the bed. I have access to a fair bit of 100mmx100mm off cuts and was thinking of using this as the base for the machine. Would this be too extreme for the gantry?

[Jonathan]

My thoughts are going towards a low level gantry eg minimum deflection in relation to the x axis with the adjustability of the bed. I have access to a fair bit of 100mmx100mm off cuts and was thinking of using this as the base for the machine. Would this be too extreme for the gantry?

Excellent. Nothing's too extreme. The worst that will happen is you might need bigger motors, or have to accept lower feedrates (which is irrelevant for aluminium cutting). Design the machine then select the electrics to suit. Don't start trying to make things lighter to optimise the feedrate since a rigid slower machine is much better than a fast weak one.

[JAZZCNC]

Excellent. Nothing's too extreme.

Design the machine then select the electrics to suit.

Completely 100% agree on both counts. . . . If you then filled it with concrete you still wouldn't be extreme, Infact if you mainly intend cutting Aluminium I recommend you do exactly that has it makes a big difference to resonance and quality of finish.!!