You need a CNC to make a CNC.

[quadrilateral]

Or it helps.
Sigh.As the title says really.So at that realization.... i have started to delve into the deep rabbit hole that is CNC.

Brief back ground...

Name is liam based in kent/london

day job is cad technician doing highways/parking arrangements (All 2D)in my spare time i play with the 3D stuff.

Did mech eng at college (and some basic G-code stuff) and motorsport eng at uni.Always had an interest in mechanical things Dad is retired car mechanic and was a cycle mechanic for 4 years as well.

Recently bought a house so DIY is my most practiced hobby at the moment...but i now have space available to store a CNC machine..

Hobbies include fishing,golf,bicycles,football and rc car.


As for the Rc cars...i Enjoy building them rather than racing and this has lead me to do a fair bit of 3d printing.3D printed a lower Centre gravity gear box for a toy car and a few side supports.



Build thread of 2 i have build...
http://www.oople.com/forums/showthread.php?t=183146
http://www.oople.com/forums/showthread.php?t=96626

i would no like to machine some chassis for them and make some other bits for my car so i thought i would use the opportunity to build a CNC machine.

Milling/cnc has always fascinated me and have started to notice allot of the DIY kits pop up on fleabay. Looking around at them they are great as they are relativity cheap to get started how ever i feel they are not always as well made as they could, more backlash (quote me if am wrong) and feel like if i build one from scrath i can 'over engineer it' if i wanted too.

Again would love help and input from people as i a newbie.

i initally drew up once from instructables.

https://www.instructables.com/id/Bui...lling-machine/




This was what i came up with:



I am fimiliar with the extruded alu profile i made a frame building jig out of it used a company called minite(but thats another story)


Recently started reading more and more about it (again) and stumbled across mikeyc38 design and this reignited my designing.
what i really like about his desing was the Y and Z axis.

So i decided to 'Borrow' the concept as it looked very neat and counterbalanced the weight of the spindle.Also since looking at his design i have looked and simplifying my design a tad to to make it cheaper/easier to make.




Left was my 'final ish' design utilised 4 45x90 profiles.To the right is a new bridge using sort of mikeys design.

My design will no be as big as mikeyc38s.

My bed dimensions will be 500 x 800 (roughly) So i am not going for a massive machine.

i will be using it to hopefully machine sheet alloy,sheet carbon,alcetal/derlin and wood.

probaly used a Nema 23 type motor and would like to used linear guides instead of rails.

have a few are i would like to address...

1.The design i have based mine up uses a bearing block that takes a '6207' bearing.
i would like to replace these with a standard of the shelf part so means less machining again.
Thsi is what he makes...sure there would be an off the shelf soulution


2.Helps on the X axis understanding what slide/block is needed to link the 'Leadscrew' to the sledge. (as it where)this would help finalise hole placement on the lower part.

3.if using 'Mikeyc38' X Y axis need to under stand how the motor would be mounted and interact with the lead screw.

3.understanding what pulleys and belts are needed.

4.understanding what ball/leadscrews are needed.


probably loads more questions as i get deeper into it.


typical,it will take a while and will try to do a bit each month when the design is final.

burnign question also is it just worth buying a kit machine of internet? (convenience etc etc etc)

Sorry if its rabmly and bit miss jointed.

Look forward to your input

liam

[Greeny]

Hi Liam,

I'm just starting a build too, so my advice is based on reading, not experience, but since no one else has replied yet.

I would advise checking out as many build logs as possible to get a feel for what is good/not so good.
There is a goldmine of information on here, from some very experienced builders.
http://www.mycncuk.com/forums/253-DIY-Router-Build-Logs

Some general points i have picked up are:
Prefer ballscrews over leadscrews except for the tightest of budgets.
Ballscrews are not much more, but are far superior in every respect.
Pre machined ballscrews with standard end fixings and bearings can be bought for great prices from china.(even with postage & import duty)
The sets usually come with a ballnut housing for attachment to your axis, although you will probably need to fashion a bracket.
Here's a couple of examples with different end mounts.
https://www.aliexpress.com/store/pro...358547478.html
https://www.aliexpress.com/store/pro...336703841.html
I only show those as examples, you will need to research the best diameter/pitch/length/end fixing for your needs.

Commonly used pulleys and belts to drive ballscrews are htd-5.
Motor mounts can be bought but are usually flimsy. Most seem to make their own.
Again check out some builds for various options

2.2kw water cooled spindles seem to be much preferred over the kress 1050. They are not much more money, but are more powerful & much quieter. General opinion seems to be the kress are less reliable too.

There is a current build of a machine similar to what you are thinking of that you might be interested in.
http://www.mycncuk.com/threads/10658...ue-welcomed%21

Cheers

[quadrilateral]

Greeny, Many thanks for taking the time to respond.

i still value your feed back all the same,

yeah i have had a peruse on through some of them i love how some just keep evolving.

Balls Screws. The alixpress likes are just the info i wanted...this helps nail a design down abiet in cad but with all the holes in the right places etc/
i have vague idea on the size i need think i would like to use 16mm.

again (HTD-5) great just what i needed to read.

after reading and i have a look and it would appear this is what i would need for my y axis

http://www.ebay.co.uk/itm/1-NEMA-23-...0AAOSwnDZT2c8w

Noted about the 2.2.kw spindle...may start out with a smaller one as my machine to start with is not massive and the stuff i plan to isnt massive.

i will have a look a your thread and have a read

Cheers

Quad

[Greeny]

No worries,

Not much on my build log at the moment,
Just finishing up the shed to put it in!

Coming soon, as they say

[Zeeflyboy]

1.The design i have based mine up uses a bearing block that takes a '6207' bearing.
i would like to replace these with a standard of the shelf part so means less machining again.
Thsi is what he makes...sure there would be an off the shelf soulution

You would be looking for "FK" type blocks for the fixed end (proper ones will be using two opposite facing angular contact bearings) and "FF" for the floating end. You just have to choose the correct size to suit the machined ends of your ballscrew.

2.Helps on the X axis understanding what slide/block is needed to link the 'Leadscrew' to the sledge. (as it where)this would help finalise hole placement on the lower part.

Depends on the size of ballscrew and the type of nut. If using 16mm and a "normal" flange type nut, then something like an HD16 - ball nut is attached to that, and that gives you a mounting surface.

3.if using 'Mikeyc38' X Y axis need to under stand how the motor would be mounted and interact with the lead screw.

Don't really get what you are asking there... looks very simple, motor bolts to mounting plate, pulleys connect shaft of motor to ballscrew through a timing belt. What's to understand?

3.understanding what pulleys and belts are needed.

Technically none... you can direct drive the ball screws if you prefer. Advantage of pulleys is that it isolates the motors from vibration more effectively, disadvantage is that you are introducing a tiny amount of flex and another potential source of backlash.

If using pulleys, a nice chunky HTD type belt is a safe bet... https://www.bearingboys.co.uk/Metric...lts-HTD-1214-c

4.understanding what ball/leadscrews are needed.

1605 or 1610 ball screws would probably be the best bet depending on whether you are going to gear down with pulleys. C7 grade would probably suffice. You can get your own ball screws machined up to your requirements but you might be better off finding some suitable "standard" type screws that give your desired work envelope and design your machine to fit them as it keeps things cheaper.

burnign question also is it just worth buying a kit machine of internet? (convenience etc etc etc)

Depends, half the fun can be in building your own machine in the first place.