New Machine Build- Steel router with adjustable bed height.

[pavlo]

I thought I would document the build of my new router and ask a few questions while I am at it.

This is my second router, the first is detailed here http://www.cnczone.com/forums/showthread.php?t=81079

This router works very well and I have someone who wants me to build a similar one for them. I didn't fancy the idea of just making the same thing all over again so I decided to let them have my machine and make myself a bigger, hopefully better machine.

The new machine will be about 2m x 1.2m with 250mm of travel in Z

I realised from using my first machine that having 150mm travel in the Z direction doesn't mean you can machine something 150mm high. To machine a tall oblect usualy needs a long cutter but this reduces the the travel of the machine otherwise the cutter is diving into the bed.

To overcome this I have decided that I will build the machine with a bed that can be manually raised and lowered so that both low and high objects can be machined without losing any travel in Z.

The bed will be supported by 4 M16 studs linked by chain and sprocket to keep them synchronised. I plan to use a spanner to wind the stud but I may in the future fit a motor.

They say a picture speaks a thousand words so rather than waffling on, here are a couple of sketches of what I am making.





I bought rails and ballscrews from ebay (LMB2008)



I bought a quarter of a tonne of box section and started cutting.



And welding.



My very understanding wife has said she would prefer it if I bring the gantry indoors to work on rather than have me work alone in my garage. God I love that woman.



So, that's as far as I have got at the moment. X and Y axis are built and just need the motors fitting.

Next job is the frame. Alas, I think I would be pushing my luck to try and get this indoors too.

I would appreciate any opinions on the best position for the dual 25mm ballscrews for the X axis. I was thinking of fitting them to the outside face of the main frame but I wonder if putting them higher would be better?


I still have loads to do but I am getting there slowly.

I would welcome any thoughts or criticism (so long as it's not too scathing)

[cyclestart]

You have rails from Chai (LMB2008) on your completed machine ? How are they holding up ? I've been checking them out on the Ebay store but have been searching for some user feedback. The ballscrews I bought from him are OK for the price.

No useful advice to offer on your design, sorry. The other possibility would be to make the bridge adjustable in the vertical direction as seen on many bridge mills. Probably not practical with a moving gantry however.

[johnmac]

Rather than building an adjustable table, why not build a deep table with a drop-in spacer? That will eliminate the need to build the adjustment mechanism.

BTW, your gantry looks a lot like mine. Right down to the rail placement and color.

John

[pavlo]

Chai seems to be a good source of cheap rails and bearings. the ones I used on my first machine are working perfectly and are showing no signs of wear yet.

I think that you have to be realistic, if you want a machine to run 12 hours a day 6 days a week then these are not the components for you. If, like me, you just want a machine for occassional use then these are a very good option.


I am already committed to the adjustable bed method although I did consider using a drop in spacer. The adjustable bed I am using will make the machine quite versatile if I ever want to add a fourth axis. This would be a bit of a pain with a drop in spacer.

[cyclestart]

Thanks pavlo. Road tested results are worth more than Ebay feedback. You're right regarding this machine being for occasional use, if it was for commercial use I'd buy a commercial machine

A ^^bump^^ for your thread

[compfranon]

CRacking build Pavlo, like the idea of the movable bed, reckon i'd have gone for a spacer though, but thats my inexperienced opinion.

Thats going to be a strong machine, wonder what you plan to make with it.

Re X axis ballscrews, is there somewhere they can be located to help protect them from the swarf being produced, or do you plan to cover them in some way.

Just wondering where you sourced that incredibly rare item .........

A very understanding Wife

Good luck with the build, keep working in the house, you'll soon end up with motorbike repair on lounge carpet approval.

[hemsworthlad]

Hi Pavlo,

I have an adjustable bed although completely differant approach to yours and it works very well.

It's nice having the freedom to cut larger over size items if needed but depending on your main work i think you'll find that you dont move it as often has you think.?
I,ve used mine now for about a year and i,ve only had to move it twice, i seem to have found a happy medium.
I cut Aluminium mostly and this was the main reason before i started the build to have a adjustable bed thinking that i would need it at it's highest setting but as it turns out the machine cuts Ali easily at any height and i,ve even cut steel with it in the mid position were it spends 95% of it's life.
The only reason i,ve had to move it was for a large piece of wood with a long cutter.

There are little things to be aware of like it can take a while to setup perfectly after you've moved it and for work that needs a truely perfectly flat parallel surface you will probably want to resurface the bed each time or surface a spoil board.?

I also use twin screws on the outside and i can tell you without a shadow of doubt you need to get them as far away from the cutting surface as poss and if pos cover them up. Also on the sides use some form of shield to stop swarf etc from flying out onto them.
Regards the gantry one of the best things i did was to put the screw behind the gantry away from the cutter, it hardly ever gets any swarf on it.

Another thing i would say regards using steel box, which you probably know if you used it on your last build, It's noisey stuff and resonates slightly so i would think about filling the box section with dry sand any place you can.

Hope this helps.

PS: sent you a pm

[johnmac]

The need for resurfacing the spoil board with each bed height change is why I thought of a spacer. Once the lower bed is surfaced, the spacer would be dropped in. Then the upper spoil board surfaced. As long as the spacer is inserted the same way each time, the table should remain level.

John