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DFMiller
02-04-2012, 02:48 PM
Finally got the column apart from the base.
Was rather surprised that they decided not to machine the base flat. Seem to be a gap.
http://i560.photobucket.com/albums/ss47/ve7pke/KX3%20Rebuild/BasetoColumn.jpg

This picture is not great but the upper screw hold has a machined spot where the column contacts the front is way low and not machined. ;-(

I guess I may be shimming it some. Or ripping it down to bare casting and starting over.

Dave

John Stevenson
02-04-2012, 03:11 PM
Aahh,
All is revealed. Could be a very, very early machine, could even be a pre production model by the colour, hammerite silver, my KX3 is that colour
Other alternative is that all the western machines were colour coded to supplier, green, white or cream and red. The silver machines went direct into china and Russia.

Russia bought about 1,700 machines for a state run schools project

I see it has a rigid coupling between motor and screw.
That needs changing to a 30mm or 35mm Oldham coupling.

DFMiller
02-04-2012, 03:40 PM
All the couplers are solid. If I ever get that far I can look at changing them.
I see why the Z slide needs work. Just by examination it looks like the oil grooves never had in oil in them. The back of the slide is "scraped" and all the oil grooves have burrs on them. The dovetails have several burrs in them. No wonder the thing binds once you tighten up the gib.

Do I fix or sell for scrap. That is the question.

I am thinking I need to put up a "Seig KX3 Sucks " website.

Dave

The Doctor
02-04-2012, 06:18 PM
Replace the couplers BEFORE you start using it. Smithy 1240 originally had solid couplers. X leadscrew broke, replaced it and added flex couplers. Y leadscrew broke about 200 workpieces later, apparently cracked by original couplers. Don't let it happen to you!


Ed

Jim Shaper
02-04-2012, 06:44 PM
You don't want a coupler that doesn't allow for slight angularity differences in something you know has poor machining. That's why the shafts are breaking, it's from repetitive stress from bending over the misaligned junction.

If you knew they were coplanar, there wouldn't be an issue. Looking at the machining you've posted, I'm putting my money that they're not. Even high end cnc's don't direct drive axes - that's what the timing belts are for.

John Stevenson
02-04-2012, 06:53 PM
High end CNC's don't direct drive their axis because they are servo driven and require a belt reduction to get torque.
Plenty of direct driven stepper machines out there that work well but they do require decent couplings.

The original KX1 was built in the UK, I still have it. All the details and drawings were sent to China and they *nearly* copied this and scaled it up to produce the KX3.

We never had any input on the KX3 until a pre production machine was flown over.

The KX1 had Oldham couplings as I never fit anything else but the Chinese in their infinite wisdom fitted solid couplers. It was only later that at our insistance they changed over to Oldham couplings on both models.