A different (better) kind of screw

[BillTodd]

I'd just like to publically thank:

Rosemary and all at Associated Springs - Barnes Group (UK) ltd

and

Owen and all at Bellevilles Springs Ltd

for providing me with the Belleville Spring washers for this project.

Thanks guys, Merry Christmas

[rokag3]

It's looking good (I would hate to have to build something this complex without the aid of a 3d modeller)

I agree specially for the screw of assembly

[/QUOTE]I'm curious (I'm sure you have good reason), why use two upper rollers on the bottom and why the large lower roller on top? (At first glance, there appears to be enough room for a single roller in each place. Thus reducing the number of different parts )

[/QUOTE]

for the Xaxis on top 2 small 27mm rollers and one 40mm roller down because :
the original support is much more slim .to install our support we must lift our support from under the table and then fix the 2 side support with allen screw since we cannot move our support the screw are with angle since this piece in steel rich in carbon must not twist every thing must be thick .

But not enough space dont forget that under we have the y axis the 2 screws are 32 mm and they are on top each other 100 mm at 90deg
for the y axis i use 4 rollers 27mm

definitely interisting to design and I make big progress with solidwork

[BillTodd]

definitely interisting to design and I make big progress with solidwork

Secret weapon:Space navigator

They are fantastic and only about 60 euro. Buy one, if you intend to use a 3d modeller for more than an hour. You will not regret it.

[BillTodd]

Assembed the Y nut for a test.

Seems to work OK, although it's not as stable as the X nut (the two rollers are almost opposite to each other so there is less pressure on the third roller)

This version has a simple grub screw adjustment for the lower roller which should avoid the problems I had with the X lead-screw height.

There's a lot of aluminium to carve off the mounting block, as there are several bits of the base casting to clear.

[BillTodd]

I finished carving the mounting block yesterday, today I made the two levers and finished it ready to mount.


Before I could mount the Y nut I had to find a way to make the X nut mount accessable from above (since the new Y nut obscures the original X nut mounts). The simple solution was to cut down the small mounting blocks I'd made, so they would clear the end of the table, then mount them to the nut with just one of the screws. The X nut can now be removed by unscrewing the blocks from the nut (leaving the mounting block in postion on the saddle). All that's required is a two foot long allen key!

The Y nut fits perfectly; Spending extra time at the design stage making sure it would fit, has paid-off The adjustable bottom roller works well; allowing the roller to support the lead-screw at the right height without having to resort to hacking the leadscrew mounting.

I might add an additional roller (probably a bearing) above the screw, at the back of the mount, just to stabilise the lead-screw (ATM leaning on the handle lifts the back of the screw a little).

There's too much play in the lead-screw thrust bearings to tell what the back lash will be like (I'll shim them tomorrow), but the whole Y axis is very smooth and feels very good (better than the X axis)

[rokag3]

hello,
great work i hardly believe you have done it this is a real challenge what sort of servo are you going to put in ?


I have not work a lot because i loose much time with the story below..
one year ago i bought a chinese ac/dc plasma mma tig 160Amp
work perfect my griend (the one of the lagun) fix motobike time to time and bought a 200A that i choose for him.
after 3 weeks we receive it (from germany) it's faster from china !
we test it and it worl perfect with steel.
2 days ago a phone call from my friend
Lucien i have a big problem full power or half power the needle melt and the aluminium make just bad cratere
do you ajust the clean balance ? yes the ground is positive ?yes you cannot put the ground to negative by mistake.
I send a mail in germany "we have a problem ..."
answear send it back i change it
before to send it I bring my tig
and i have the same result
F......g chines c..t say my friend
then we look at the green bottle of argon
given for little money by a guy who wanted to sale a tig 3 time more expensif.
let's take my bottle !
magic both tig was making perfect lake and a perfect cord was done

The argon was not argon

because every one is suspicious the idea was to make my friend going in court and making bad advertissement.
So the quality of the gaz is fondamental if you buy a chinese tig do not say it to your gas/tig retailer

[BillTodd]

great work i hardly believe you have done it this is a real challenge

Thanks Lucien but I suspect your Lagun mod may well prove to be a greater challenge

what sort of servo are you going to put in ?

I have to sort out the Z axis first.

I have a couple of ~100w DC servo motors with encoders. I was looking at Geckos but their price has effectively doubled since the decline in the value of Stirling.

I've been following an open source design PIC based design in another thread; I have PIC programming tools, so I perfer this to the AVR/UHU design. Max-Mod (a countryman of yours) has been developing an H-bridge version but has yet to publish a working design. [I read/understand a little French but I've not figure out what the hold-up is: http://www.usinages.com/carte-servos...-t648-180.html]

The argon was not argon

Malicious or just a Cock-up ?

[BillTodd]

I shimmed the lead-screw thrust bearings, but not quite enough. So, I tried tapping the lead-screw like the X axis. In my haste I broke the tap...Idiot! Grrrrrhhhh


In an attempt to measure the back-lash I attached my Peacock micron dial gauge between the Chuck and the table:

Pulling and pushing* on the table in the Y axis I can spring (moves then returns) the table +/- 20um of which ~20um is back-lash. I suspect about half this in still the thrust bearings.

(*enough to hurt my back again! having 'tweeked' it yesterday in the cold)

Trying the same test on the X axis: I can move it ~+/-25um (simply leaning on the end of the table moves about as much). The back-lash appears to be ~ 6-8um.

To put the above figures in perspective, using one finger only, I can spring the chuck +/-10um!

These machines were not built for great precision

I'd be interested to know how this compares to other machines (with or without ballscrews) - {Paging: Kipper and Bob Warfield}

[rokag3]

Malicious or just a Cock-up ?

Malicious !

[rokag3]

These machines were not built for great precision

yes but the value you have could make many owner of ballscrew envious

HELLO READERS GIVE FEED BACK HERE PLEASE

[EvanVH]

What a great idea. I have an old lagun that would love to have a set. Anyway great read when I start my project I will be emailing you with questions.


Thanks



Evan

[rokag3]

hello,
finally want to make it monobloc he does not like screw so here is the last proto i have done

all the problems are not solve yet.
so far the roller is the smaller problem
the big problem is the installation thats why the wings are not monobloc