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I agree about placing the bridge in the middle rather than at the top.

Just needs to be higher than the max workpiece height (so about level with bottom of spindle when fully up).

There are a number of servo sizing calculators available which will give you a good answer.

Sigma have one.

Kollmorgen....

5 thousand for machining?

Surely these are actually simple parts to machine? Face rail mounting, drill and tap a few holes?

How many hours / hourly rate?

I vaguely remember something about DYN4 being better in terms of input / control options and preferred?

If cost is similar I would go for DYN4 and avoid DC

How high is your table?

Why direct drive for servo.
You can use a belt and have the servo out the way.

Any decent seller will machine to length.

I wouldn't buy from a seller who won't machine to length as it means it is not their main business and they are probably just drop shipping.

Down cut spiral bit for a clean top surface.

I think about 3-4mm.

I did read (after building my machine...) that you need 1/4" thick for self leveling. That's getting very thick. My experience does fit with thin pours not working well. I did...

Nice build.

I used epoxy poured on steel tube for my gantry. I used West system with super slow hardener. I thought it was a good technique until I got better measuring tools. Then I found the...

Ball screw lead error can be compensated for by screw mapping. Which is done with glass scales.

I agree that the first priority should be to eliminate mechanical error, including backlash.

Delta B3 series don't need a special cable - just mini USB.

I have a Delta B3 750W servo I'm using as small lathe spindle. Very happy.

Cost for a BE seemed to be similar to B2 on fastotobuy...

DMM or Delta AC servos.

Do not waste time with poorly documented generic servo drives.

Or steppers - easier.

Google nook ball screw critical speed calculator

2 ton is a next step up. I'm hoping to keep mine in the easier to handle range. Parts (base, columns) less than 500kg can be handled with an engine hoist or similar.

Pipes etc in the casting do...

I know you've posted about grading / single aggregate before Peter. As a mug (untrained individual) I'm not sure what to believe.

I see what you are saying about industry wanting different sizes...

I'm not convinced that a large solid is better.

A diagonal grid can be achieved by using polystyrene foam inserts.

A diagonal grid is a very stiff structure. What else would you propose?

Totally correct, I was coming back to edit the post to say "use material where it is needed"

Solidworks

I understand all those principles.

But if weight (and material volume cost) is any consideration (both are certainly important for the hobbyist) then a solid piece is not optimal.

See attached...

"Nanodur Concrete E80 a class of its own
The secret of this unique international development is the exchange of natural stone with the industrially enhanced aggregate durigid. It is submitted to...

Filling a steel tube does have benefits.

There are a number of research papers as well as:
https://durcrete.de/technical-data-nanodur/?lang=en...

Durcrete are using multiple size aggregates.

https://www.youtube.com/watch?v=tjEpMHwJ8Qs&feature=emb_logo

I'm interested in how you go with ALOX / CSA mix (need a catchy brand name to hide what it is - ausidur?)

I wouldn't mind if it's more $/kg than epoxy granite. We should be looking at $/stiffness...

Why are the Y rails at the extremes?

I don't see any attachment / photo on any of your posts.

Photo or drawing of the finished part?

Just cut outs of a stock aluminium box?

Do you have other designs / parts to make?

Servos:
Why would you need to change the belt reduction to gear reduction?

There are many more AC servos driven by 220v/230v than 110v

Pathpilot follows the convention of describing the tool movement relative to the workpiece.

Cartesian axes (X Y Z) are the same as graphs. X is horizontal (left to right). X positive will move the...

You don't need 2m for 1m of travel. It depends on your bearing spacing.

You won't want the bearings right at the corners of a big table - that would result in the biggest unsupported span.

A...

I am not in the US but I believe McMaster Carr will not be a cheap exercise.

Virtually everyone doing hobby machines buys from China.

"BST Automation" on AliExpress (Google it) is reliable...

Square rails (most) have equal load capacity in all directions.

Unsupported round rails also do but are floppy floppy floppy

Supported round rails do not have equal load ratings - depends on...