1220 × 2440 build

[JAZZCNC]

What dimensions are those gantrys Dean?

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Gantry is HD Item section 120 x 80.
Frame is 100x100x6

[JAZZCNC]

Here's design that will allow you to be more flexible with the frame. Although the base here is in one piece it could easily be made in 2 or 3 pieces and bolted together.
The important part is the full-length profile section running full length down each side. This will allow you some flexibility in adjustment so can get both rails on same plane without messing around epoxy resin etc. Must stress thou the accuracy will only really be good enough for cutting woods and softer materials. It will also take lot of setting up and tweaking until spot on.
In my experience profile is relatively flat and straight enough for wood router and does make fitting rails, ball screws etc much easier. The downside is cost so mixing steel and profile gives good balance of strength, costs and accuracy with ease of building which doesn't require too much machineing or timely and costly techniques for leveling etc.

[HullMark]

So it definitely sounds like building my own will be best option as I'll know exactly what I'm getting/ putting into the machine, so long as everything's accurate and I take into account all the issues learnt so far by everyone else. Oh and spend a little more too!

Jazz, that makes perfect sense. I was wondering how slowing down the speed of the screws would effect the whip that's been mentioned. Hopefully that'll be a cheaper fix for Malcolm! Thank you for sharing your progress malcom, ill be sure to keep in touch and up date with any developments ... Is the vertically mounted CNC one of yours jazz?

[Clive S]

Is the vertically mounted CNC one of yours jazz?

Yes it is I have personally seen it. Why not ask him for a quote? He is not to far from you.

[malcolm01]

So it definitely sounds like building my own will be best option as I'll know exactly what I'm getting/ putting into the machine, so long as everything's accurate and I take into account all the issues learnt so far by everyone else. Oh and spend a little more too!

Jazz, that makes perfect sense. I was wondering how slowing down the speed of the screws would effect the whip that's been mentioned. Hopefully that'll be a cheaper fix for Malcolm! Thank you for sharing your progress malcom, ill be sure to keep in touch and up date with any developments ... Is the vertically mounted CNC one of yours jazz?

I wonder how I’d go about fixing the other end. It has a floating bearing, it’s only held on by a sirclip, other end is designed to be fixed 🧐


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[HullMark]

Without seeing something Malcolm, with my inexperience, I'd find it difficult to offer any kind of solution. I've seen parts available on a uk website CNC4YOU ... seems to be a lot cheaper than I've been advised here for screws and bearings. Anyone used these guys before? There's fixed and floating bearing supports for sale on there Malcom if that's of any use.

[malcolm01]

Without seeing something Malcolm, with my inexperience, I'd find it difficult to offer any kind of solution. I've seen parts available on a uk website CNC4YOU ... seems to be a lot cheaper than I've been advised here for screws and bearings. Anyone used these guys before? There's fixed and floating bearing supports for sale on there Malcom if that's of any use.

That’s where I bought the lot from. Fixed at one end and floating at the other.


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[JAZZCNC]

I wonder how I’d go about fixing the other end. It has a floating bearing, it’s only held on by a sirclip, other end is designed to be fixed

Hi Malcolm, As you have probably gathered by now the Ends will need machining to fit the Fixed type bearing. However, this alone won't make a massive difference it's the screw speed that is Key.

I've seen parts available on a uk website CNC4YOU ... seems to be a lot cheaper than I've been advised here for screws and bearings. Anyone used these guys before?

You will buy the same stuff from China a lot cheaper than he sells them.! . . .Where do you think he buys them.?
China at the minute is on Holiday but when you have the design nailed down and know lengths etc then Email Fred here for a quote.
https://bstmotion.aliexpress.com/store/314742

[routercnc]

I wonder how I’d go about fixing the other end. It has a floating bearing, it’s only held on by a sirclip, other end is designed to be fixed ��


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I'm in the process of doing just that on my new Mk4 machine on the long X axis. Because of the arrangement in the design I will not use off the shelf parts - instead I will be re-machining the floating end to have a lock nut and thread, and then use a thrust bearing between the lock nut and radial bearing to vary the axial pre-load. I'm likely to need a spacer in there to ensure force lines pass through the right part of the bearings. Hopefully when I get the video out (could be a few weeks yet) it will be clearer, and in my case it should make a neat job of it.

Alternatively, and easier if it can be done on your machine, you can use the same fixed end bearing set (that you have at the drive end) with angular contact bearings in to apply the axial pre-load, but you would need access to a lathe to machine the floating end of the ballscrew to suit. Then to apply preload to the ballscrew depends on how it is bolted to the machine. If the bolts run through the vertical holes then you just need to pull the ballscrew tight and torque up the fasteners. If the bolts run through the horizontal holes you need some way of shimming it away from the mounting face to get the axial load applied.

edit: apologies, realised I've replied to a poster, not the OP. Malcolm, create a new thread if you want more.

[malcolm01]

I'm in the process of doing just that on my new Mk4 machine on the long X axis. Because of the arrangement in the design I will not use off the shelf parts - instead I will be re-machining the floating end to have a lock nut and thread, and then use a thrust bearing between the lock nut and radial bearing to vary the axial pre-load. I'm likely to need a spacer in there to ensure force lines pass through the right part of the bearings. Hopefully when I get the video out (could be a few weeks yet) it will be clearer, and in my case it should make a neat job of it.

Alternatively, and easier if it can be done on your machine, you can use the same fixed end bearing set (that you have at the drive end) with angular contact bearings in to apply the axial pre-load, but you would need access to a lathe to machine the floating end of the ballscrew to suit. Then to apply preload to the ballscrew depends on how it is bolted to the machine. If the bolts run through the vertical holes then you just need to pull the ballscrew tight and torque up the fasteners. If the bolts run through the horizontal holes you need some way of shimming it away from the mounting face to get the axial load applied.

edit: apologies, realised I've replied to a poster, not the OP. Malcolm, create a new thread if you want more.

Yes I understand now. Ooft they’re 2.6m long, I have little engineering knowledge I’m a joiner.


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