Tools – Metalworking

[Hammer]

For the proxxon tolerance... at this point 1-2mm would be awesome... how can you make repeated pass without going back. If i repeat my x passes i always clear 1 mm on y when pulling back. with the backlash as it is it's like having to reposition the stock for every pass...

Even if you go back and forth but are always cutting in the same direction (i.e. you're only backing up to make another pass) it should be pretty accurate, since you're always pushing the bed with the same edge of the screw (assuming your bit is rotating in the right direction re. the workpiece). If you move to the other side of the workpiece to cut in the opposite direction you'll need to recalibrate.

I don't know how complex your cuts are, but for basic straight cuts, one at a time, it's not a huge problem.

I know some guys have added feed motors and CNC control to those Proxxon mills, and I can't see that working very well without some serious modifications to the bed.

EDIT: By the way, 1~2mm is way too much. That would have to be more than just screw backlash. If I remember correctly mine is about 0.45.

[Gaspard de Coligny]

Yeah I saw the japanese made cnc upgrade for proxxon...

ridiculousmand overpriced.

I hace to dig back the links, butnthere is some chinese tech startup that make cheap tweakable cnc kits. you slect the drivers you want, add the axis you need... seems excellent...

[Hammer]

Coligny, how are you measuring things like backlash and workpiece positioning?

If you don't already have one, I'd recommend something like this:



The one in the back with the yellow dial (slightly out of focus ... sorry about that) is a "dial test indicator." The tip swings on this type. You clamp it in the chuck, where the bit would normally be, then with the tip against the workpiece or any object clamped to the table, you can measure table vs. bit positioning very accurately. If you're not measuring backlash accurately, you can't compensate for it very well.

The larger one in front is a regular dial indicator in which the tip moves in and out to measure relative position (there's a bracket on the back of the dial that allows it to be clamped or bolted to just about anything).

These things are handy for lathe work too (like for centering the workpiece, testing for roundness, etc.).

[Gaspard de Coligny]

Got them both... but the yellow kind one still baffles me...

Chinese CNC:

https://sites.google.com/site/cncdiyorg/

[BigInJapan]

Got them both... but the yellow kind one still baffles me...
Chinese CNC:
https://sites.google.com/site/cncdiyorg/

Have you gotten anything from these guys? If so, how was the quality and reliability?
I'm looking to build a CNC like their BORSH 9060 or WALTER 6545 for working with wood, plastics, and maybe ceramic tile (aluminum etc. would be a bonus, but not necessary).
(The site hasn't been updated for over a year, and they don't have their own domain name, not too confidence instilling...)

[Ol Dirty Gaijin]

backlash issue = ballscrew.
Pre-loading the axis can help overcome some accuracy issues as well as having a consistent tool load. The tool load is harder to do without software though...
With the robots I do a backlash test on each axis and a laser tracker. You could do a similar test with the micrometer by shuttling back and forward one axis at a time and seeing the deviation from home. 1-2mm seems like agricultural tolerances! Is it only in 1 axis?

[Gaspard de Coligny]

Got them both... but the yellow kind one still baffles me...
Chinese CNC:
https://sites.google.com/site/cncdiyorg/

Have you gotten anything from these guys? If so, how was the quality and reliability?
I'm looking to build a CNC like their BORSH 9060 or WALTER 6545 for working with wood, plastics, and maybe ceramic tile (aluminum etc. would be a bonus, but not necessary).
(The site hasn't been updated for over a year, and they don't have their own domain name, not too confidence instilling...)

yea, seems they are dead... back to some japanese company (same that do a proxxon cnc upgrade)

[Hammer]

backlash issue = ballscrew.
Pre-loading the axis can help overcome some accuracy issues as well as having a consistent tool load. The tool load is harder to do without software though...
With the robots I do a backlash test on each axis and a laser tracker. You could do a similar test with the micrometer by shuttling back and forward one axis at a time and seeing the deviation from home. 1-2mm seems like agricultural tolerances! Is it only in 1 axis?

Robots? What robots?

("Agricultural tolerances" ... )

[Ol Dirty Gaijin]

Robots? What robots?

("Agricultural tolerances" ... )

Fanuc, Motoman, Kawasaki industrial. A motion system is just a motion system in my eyes. Principles are the same.
Previous work with CNC software and also laser cutting machine design.

[Hammer]

Robots? What robots?

("Agricultural tolerances" ... )

Fanuc, Motoman, Kawasaki industrial. A motion system is just a motion system in my eyes. Principles are the same.
Previous work with CNC software and also laser cutting machine design.

Oooh ... industrial robots. And stuff.
We'll probably be attempting to pick your brains at some point.

[Russell]

Did you do something against the comical backlash on the proxxon x/y bed ? it's getting on mah nerve big time these days...

Do you mean this product?


http://www.proxxon.com/eng/html/20150.php

[Gaspard de Coligny]

KT 150 sliding table, awfull plastick handles with printed sitckers for graduation (index is casted in the plastic but feels really like junk)

[Russell]

KT 150 sliding table, awfull plastick handles with printed sitckers for graduation (index is casted in the plastic but feels really like junk)

So, is this the one that has a slack of 1 to 2 mm in one direction, or is it a different model?

What better alternatives are available instead of Proxxon?

[Gaspard de Coligny]

KT 150 sliding table, awfull plastick handles with printed sitckers for graduation (index is casted in the plastic but feels really like junk)

So, is this the one that has a slack of 1 to 2 mm in one direction, or is it a different model?

What better alternatives are available instead of Proxxon?

Not slack, back(s)lash... mean if you turn counter clockwise then stop. the motion of the table stop but if you then start turning clockwise the table won't move before the handle makes half a turn or one full turn so the gearing is in contact to produce motion again. Since without Digital read out, you are left counting the number of handle turns to know the distance you travelled. backlash is totally zee sux...

There are plenty of solution for this... starting with buying super expensive x/y tables, or putting nylon parts or ballscrew, or springs. Personnally, my workshop feel excessively hostile too much mess, too dirty, too inorganised and no full size posters of Yua Aida or even a Maz 543... So I never stay long enough to really machine anything properly therefore never get to fix these thing or even finish the dro... it's more aboot machining something as dirty and quickly as possible to leave the room as fast as one can...

[Gaspard de Coligny]

After litteral days of dumpster diving in my bookmarks, finally found the japanese CNC company making promising stuff for not too heavy prices...

http://www.originalmind.co.jp/products/minicnc

Still not unpacked the lathe

But really have to check it because when opening the accessories I notice few parts missing with the thread dies holder... so better check soon...

[Gaspard de Coligny]

Also, highly recommand this buk:

The home machinist handbook,

http://www.amazon.com/Home-Machinists-H ... 0830615733

is plenty picshure and include example project... level: clueless beginner

[Gaspard de Coligny]

Finally unpacked the Mr Meister lathe...

All the indication labels didun't react well with the packing grease and are peeling of, the aluminum plate with the index stamped for the dials is not straight and or wrinkled. AND it's not turning... which is awesum for part of the device that is made of 2 switch a speed selector and an electric motor... hard to be more simple...

So either i'm missing a really small unpacking step or it's DOA...

Seriously, even without the DOA part... the chinese would never make such a crap product... maybe 10 years ago... but not today... Made in Japan YAY...

[Gaspard de Coligny]

After double checking everything. The safety fuse was broken(not really blown, more loose filament inside) replace with one from the fusebank (i have spares for nearly every kind of fuse used on this planet, one of my other hobbies (yes, including russian trucks)). So now it's working... but still not exactly a masterpiece of japanese craftmanship...

[Hammer]

I was under the impression that the Mr. Meister lathes were made in China.
You sure it's made in Japan?

[Gaspard de Coligny]

I was under the impression that the Mr. Meister lathes were made in China.
You sure it's made in Japan?

The manual say Toyoas / Tokyo Japan...

But check the bottom price minilathe made in China by Sieg. They look like professionnal hardware.