Small rigid router - Design advise needed

[Blackrat]

belts aint gonna make it any smoother .... id run a coupler on the two axis' , so much easier and cheaper

im not quite with you on bolting it to a table ? you HAVE to join either sides , no ways you going to cut ally decently if they are seperate from each other, not to mention the nightmare of trying to get them parallel by clamping to a table

[Clive S]

I am no expert but if you follow this forum and take notice of the Master's on here, coupling with belts helps to eliminate resonance which can stop a motor dead in its tracks. Try running a stepper with a loose mounting to see the effect. ..Clive

[mitchejc]

Thanks for the feedback Blackrat. I also like the simplicity of direct drive but quite a few people here believe belt-drive is the better route. I don't know how much better?

The table/base will be a very sturdy steel frame so the two sides are build separately but when bolted down they are connected via the base or am I maybe misunderstanding your question. I guess I can also weld them to the table but that won't be much stronger than having several bolts on each side of both or will it? I thought bolting them would make the alignment easier.

belts aint gonna make it any smoother .... id run a coupler on the two axis' , so much easier and cheaper

im not quite with you on bolting it to a table ? you HAVE to join either sides , no ways you going to cut ally decently if they are seperate from each other, not to mention the nightmare of trying to get them parallel by clamping to a table

[EddyCurrent]

With regard to the base, you need to post some drawings I think. With anything, you need good solid foundations to build from.

[mitchejc]

Yep, you are right, I'll do the drawing for the base and post it as its obviously an integral part of the design.

With regard to the base, you need to post some drawings I think. With anything, you need good solid foundations to build from.

[Blackrat]

The table/base will be a very sturdy steel frame so the two sides are build separately but when bolted down they are connected via the base

thats not going to work

no ways you gonna bolt it together so that the rails come out within a decent tolerance ....
have a read about epoxy leveling a frame if you havnt already ?

[mitchejc]

I'll try and get the drawings done, but the picture I have in mind is basically a 4 legged steel tube structure made from 80x80 tubing with lots of support under the table and space inside where I can sandbag the whole thing to add lots of weight to the base. I then epoxy level the top of the steel base to get that flat, bolt 2 layers of good quality birch ply + a 5mm steel sheet on top. Then bolt the gantry sides to that surface and epoxy level them before the rails go on. Does it sound practical or are there an easier way to build a sturdy base. I started off with the idea to do a concrete slab on top of a steel structure but there's just to many issues with that approach.

thats not going to work

no ways you gonna bolt it together so that the rails come out within a decent tolerance ....
have a read about epoxy leveling a frame if you havnt already ?

[mitchejc]

Ok this is roughly what I have in mind for the base. Idea is epoxy level the top of the base just to get it +- flat and level. Then put 2 layers of 16mm sealed birch ply on top and then a 5mm steel plate and secure that to the base with bolts. Apart from using bolts I really don't see another option of how to secure the machine to the table? I'm referring to the red parts in the second picture. I really don't want that to be the weak point so I'm open to suggestions. Am I approaching this the wrong way to wanting to build the router and base separately? Any advice would be greatly appreciated!

[Boyan Silyavski]

IMHO:

- no need for such a beast table.

Use 100x100x4 or 100x100x3 and make something similar like i did, worked quite well. Its simpler, cheaper and easier to make. At the back you can see the same design but with legs. See post #53



-Z belt length bothers me. See how i did it. post #109

[mitchejc]

@ silyavski
Thank very much for the reply, I was hoping you would have a look at my design. Your build really inspired me to go the metal route!

Point 1: Agree 100%. After calculating the cost for that brute of a table I realized I have to scale it down a bit so I'll do that
Point 2: The belt length is also bothering me. I really like the way you did yours but I have a bit of a problem because I already have a 350mm long ball skrew for my z and also my steppers which are very long so there's just no way I can do it the same as you did yours. My compromise at this stage is to make the gantry top narrower to move the stepper closer to the ballskrew or go with the long 650mm belt. Which one do you think is the better option? I think my wife will poison me if one more parcel with cnc parts gets delivered here so getting a longer ballskrew is not an option

IMHO:

- no need for such a beast table.

Use 100x100x4 or 100x100x3 and make something similar like i did, worked quite well. Its simpler, cheaper and easier to make. At the back you can see the same design but with legs. See post #53



-Z belt length bothers me. See how i did it. post #109