Quote Originally Posted by JAZZCNC View Post
Ok I'll shoot first.!!

Please take what I'm about to say has help rather than pulling a design down.!!

That gantry is miles too narrow and it 99.9% will twist and rack even if you use 4 bearings in the arrangement you show. It will 100% rack if you use a single down the centre ballscrew using this arrangement.?
It does need 4 bearings but not like you have them drawn. They need to be in-line side by side creating a wide foot print.

The gantry cross bracing (Y axis) is no where near enough and it will flex with Y axis sides ways movement, 2 of those pieces would work much better.

If you are going to use this narrow profile then I would recommend you fasten wide plates at the bottom for the bearings to mount side by side.
Also some corner bracing wouldn't hurt.

Don't know where your inspiration for this machine comes from but it has a very Merchant dice feel to it and if so then let me tell you they are rubbish design which flex and move around like quivers jelly.!!
I fully take on board your comments jazz.

I can see now with slightly less blinkered eyes that the opinions so far have a good grounding behind them.

My only option is to start from the original sketch, assess and improve where ever i can.

Even if it serves no greater purpose than an expensive learning curve and thats the only benefit ive gained from doing this project at least i can put that expirience under my belt.

As for the merchant dice thing yes i did look at those, and designs from youtubers, neo7cnc and hamrx8 for some of the inspiration for my design, that and i was able to come by the aluminium i have used for free has left me with what i have.

Im not too disheartened, but will glady accept any furth help your willing to offer.


as for the greater foot print for the base in x, how about if i mount two pieces of 40 80, long side vertical, inside the frame, top edge of the 40 on the same plane as the under edge of the table top, and on these pieces mount each side a linear rail to meet 4 linear bearings on the carraige that way?

thanks again.