I am a newbie in a box way world, maybe you guys can help me?

[Sofya]

Disclaimer: I don't know if this a dumb question, but I really need help so please don't judge me

I am currently designing a CNC Machine and thinking about making a box way system instead of a linear motion guide. Since the stroke of the machine is quite large and it is difficult to get any grinding machine to get it done, is it possible to have both surfaces of the box way covered by turcite B? Or is it has to be one cast iron and one turcite B surface?

 

[machtool]

You can not run Turcite against Turcite. You need a differential hardness.

I fail to see how that solves your problem? You have one long axis, in which you don't have a grinder long enough to make. How does cladding that with Turcite take away the fact it needs to be the datum? Flat / straight etc.

 

[DMF_TomB]

main point with Turcite is the turcite worn half can have Turcite reapplied and Turcite machined. the Cast iron other half often needs remachining but normally its small amounts like <.004" cause metal last longer than Turcite

 

[cameraman]

@Sofya what size is your intended travel / travels ?


Don't have a giant gantry style Okuma surface grinder no problem...

^^^ (re- introducing) the... Janko- grinder; makes you think though in terms of what can be improved upon if in a real jam and held at gun point.

Re machtool's point about flatness / datum … Hand scraping seems to have endured for a very long time (I think) simply because large cast iron assemblies can be rendered to extraordinary levels of flatness and straight ness (if you know what you are doing / have experience / skills .) without having to buy a giant multimillion dollar surface grinding machine.


Depending on length of travels; you may have to get familiar with the correct use of autocollimators for mapping out flatness straightness and parallelism.


@Sofya a good reference for some of these more traditional techniques IS (still) "Foundations of Mechanical Accuracy" (Wayne R. Moore ). Slight twist on the box way method though … (more reminiscent of surface grinder layout and design).


Depends on the machine you are building... prepping surfaces for linear rolling element guides is a lot less time consuming and in terms of motion have greater sensitivity / response / lower friction but still need to be pretty damn rigorous geometrically.

 

[2outof3]

Why do you want to build a new box way lathe? What will be special about it?

 

[DMF_TomB]

industry trend this century has been for cast iron slides and turcite covered slides to get finished by milling never seeing a grinder
.
CNC that read .00001" on XYZ and .0001 degree on B axis thats .0001"per 57" on B axis is whats being made to machine slides
.
even older machines that only read .0001" and .001 degree can do a lot with care. not unusual to machine 5 to 10 larger parts 1/2 ton each or more per day. hand scraping obviously would take a lot longer
.
only time i see hand scraping is to put a oil retention pattern on a surface. not to correct alignment its merely basically roughing up the surface to hold oil. not unusual for milled surface to be shiny and see the reflection of a tool

 

[dandrummerman21]

errrrr, Really?!?!
.0001" is rough is it? Where .00001" is good?
Just because the machine reads to that resolution, doesn't mean it's geometrically accurate to that resolution.
Or repeatable.

His are!

Actually I am pretty sure I can turn our 1993 40" Taiwanese mill with Fanuc 0m control into a machine that can show .00001 resolution on the screen. Shouldn't that make it worth 5x as much?

The idea of turcite on turcite made me chuckle. Skip the turcite and just get some teflon on there. Kinda works on cheap 2 cycle engines, why not huge precision machines???

 

[michiganbuck]

Straight accurate parallels made of steel or iron might be precisionly spaced and act as box ways, Then as wear might dictate may be renewed to near dead flat.

 

[DDoug]

I don't see where the OP indicated "Lathe".

 

[michiganbuck]

A very fancy rail or box travel might be one that runs on an air cushion, like an air spindle. it would be self cleaning and very easy travel..Guess If I hit the lotto I will/might build a surface grinder that long and cross travels run on air... but actually it would not be much better than scrapped oil ways.

 

[angelw]

A very fancy rail or box travel might be one that runs on an air cushion, like an air spindle. it would be self cleaning and very easy travel..Guess If I hit the lotto I will/might build a surface grinder that long and cross travels run on air... but actually it would not be much better than scrapped oil ways.

Hello michiganbuck,
If I won a lot of money on Lotto, I'd do one of two things:

1. Spend half on Wine, Women and Partying. The rest I would just splurge.

2. Keep on doing engineering work until the money ran out.

Regards,

Bill

 

[angelw]

I don't see where the OP indicated "Lathe".

Hello Doug,
What sets it apart from other lathes and makes it special, is that the OP is calling it a "CNC Machine".

Regards,

Bill

 

[michiganbuck]

re: OP is calling it a "CNC Machine"
Could be a router/ laser / water jet or the like CNC..

 

[DDoug]

Hello Doug,
What sets it apart from other lathes and makes it special, is that the OP is calling it a "CNC Machine".

Regards,

Bill

You doo engineering work ? with your reading comprehension ?

 

[Speedie]

Jankogrinder....what a great idea

 

[Vancbiker]

I'm want to see the OP and DMF_TomB come up with a machine design. It'd be Sweeeeet!

 

[angelw]

You doo engineering work ? with your reading comprehension ?

Nothing wrong with my comprehension, however, I'm not familiar with the word "doo".

A tongue in cheek comment relating back to 2outof3's comment in Post#5, where he asks:
"Why do you want to build a new box way lathe? What will be special about it?". Accordingly, the only thing special about the Lathe that 2outof3 incorrectly gleaned was being built, is that the OP is calling it a CNC Machine.

Regards,

Bill

 

[michiganbuck]

I tyhimnks the word is "Doo Doo"

OT: just measured the CD clear wrapper and it is very close to .001..good to keep a bit for close grinding tweaking a part or set-up..

 

[2outof3]

Nothing wrong with my comprehension, however, I'm not familiar with the word "doo".

A tongue in cheek comment relating back to 2outof3's comment in Post#5, where he asks:
"Why do you want to build a new box way lathe? What will be special about it?". Accordingly, the only thing special about the Lathe that 2outof3 incorrectly gleaned was being built, is that the OP is calling it a CNC Machine.

Regards,

Bill

My assumption which was not corrected or commented on by the op.

 

[Perry Harrington]

Those big old Tree mills used bolted on ground ways which sat on pedestals. I see no reason why you couldn't grind accurate bars, then bolt them on. Then again, why not just buy big honkin' linear rails and be done with it?