Sizing Dro Scales on Sieg sx2 Plus

[Buell]

Im just about to order a Chinese set of  Dro scales and Display for a Sieg SX2 Plus its basically the sx1 with a larger table I think.

Anyway have measured up and wanted a 2nd opinion if i have gone wrong here in my sizing or idea.

The x travel is 280mm and the Bed size is left to right 400mm
The Y Travel is 150mm and the carriage size is front to back 220mm
The z Travel or height of complete column is 500mm.

Now the Scales are in 50mm increments...so in theory if you want a travel of 280mm you would choose a 300mm ? which then the Physical length is 300 + 150mm or thereabouts for mechanism. which in theory means its going to be longer than the Bed..

Have i Missed something obvious ?

Many thanks in advance also anyone bought from Aliexpress, bangood, Ebay etc with good results , and whats the deal with the Shipping duty thing does that kick in or do they generally say its worth a dollar to get out of it ?

[philf]

Buell,

Sino do 16 x 16 section scales and do a 280 mm scale. The overall length is 383mm. The range is called KA200.

I bought the system for my lathe from the UK so can't comment on buying from China.

Cheers.

Phil.

[chipenter]

You need to add the size of the read head to the length plus clearance .

[Buell]

Thats what i thought so it will stick out 10 to 15mm at either end of the bed. So when i have seen most scales they all seem to be either shorter or the same length...thus they wouldn't have the Full travel of the machine ?

[WeldingRod]

I would buy the long scales about the length of the table; makes mounting easier.
It they are the Aluminum/circuit board capacitive style, then they are easy to cut.

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[mc]

150mm for the reader head length seems excessive.

What scales are you looking at?

There are various options depending on how much space you have available.

[chipenter]

I made my mounts the same size as the table on my X1 that has the same table .

[Buell]

My plan was to use the Glass scales. approx £170.00 all in 3 scales and a Dro display gives you all the whistles and bells...circle diameter with holes set ..points to go back to and many other. I guessed if i was to spend £100 on cheap stuff i may as well go large and give my self a fighting chance of doing some of the other things i may find myself wanting to do in the Future. They have i guessed a small level of glass in them so Not very adaptable ! but yes i think i will go for as near as the same length as each axis..Thought if i go for the 500mm for z Then if I ever take it off and get a bigger machine may have the chance to use in one other location !

[Buell]

something like these ?

https://www.aliexpress.com/item/Free-shipping-new-3-Axis-digital-readout-with-linear-scale-100-1020mm-5micron-linear-encoder-complete/32822557854.html?spm=2114.search0104.3.8.6b58750dFj2rju&ws_ab_test=searchweb0_0,searchweb201602_4_10065_10068_10130_318_10547_319_10548_5727315_10696_450_10192_10190_10084_10083_10618_452_535_534_10307_533_10820_532_10301_10821_10303_204_5727215_10059_10884_10887_100031_320_10103_448_449,searchweb201603_60,ppcSwitch_0&algo_expid=be03cc01-04f5-45dd-b9bf-3b436b8a6300-1&algo_pvid=be03cc01-04f5-45dd-b9bf-3b436b8a6300

[mc]

Those are the more common size of optical encoders, but you can also get a slimmer version, which can be handy especially on the Y-axis where mounting space can be at a premium.

I'll send you a PM with some details.

[chipenter]

Does this help ?

[Will_D]

Here's a link to my thread about fitting DRO to my SX2P:

https://madmodder.net/index.php/topic,10428.0.html

HTH Will

[Buell]

So im told in theory I could make a Power feed with a stepper motor thus creating a Dro ? So im looking into that now as this seems a double hit it i can use it manually sometime as-well in some config.

[WeldingRod]

Four drawbacks: it doesnt read the backlask, the screw error, manual motion, or lost steps right.  If you fitted one with an encoder, you could take out the last two problems for a small outlay.
There are cheap quadrature counter modules out there, in regular, waterproof, and instrinsically safe (not going to cause an explosion).  I've used all three for regular and backup depth readouts on machines from 10 to 160,000 pounds.

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[Buell]

Thanks for that think this is going toward a simple Dro set of individual readouts and a stepper to drive the x axis to save my shoulder and cranking..maybe in the future if I get to grips with the Stepper and controls I will convert to Cnc..But i don't think thats me at the moment, as there are just to many things to learn let alone build !