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Are those rails symmetric? So that they can be "inverted"?
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Yes, they are just 8mm stainless round bar. But at a guess the mountings - one at each end - are misaligned, which would "push the middle up" so as the trolley moves on it's linear bearings it physically lifts and then drops down again.
Just loosening both ends of each rod should show that, if that's the case, and a little BF'n'I* to the end mounts may fix it.
You'd be surprised how much solid metal flexes: Lathe Leveling - YouTube[^] what from about 13 minutes to see the effect of raising one foot on a 2 ton lump of cast iron by 1/4 inch!
* Brute Force 'n' Ignorance
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
AntiTwitter: @DalekDave is now a follower!
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Best part was the comment in the end: "Machinery maintenance isn't that exciting"
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I like ThisOldTony - I own no metalworking stuff, and I'm not about to buy any, but he just knows what he is doing, and explains it both well, and entertainingly. Not something you can say about 99% of all YouTube software videos ...
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
AntiTwitter: @DalekDave is now a follower!
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Oh, and the casing should help with warping, as it makes the internal temperature more uniform.
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
AntiTwitter: @DalekDave is now a follower!
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I've just repeated my "bed map" with the DTI:
-3 18 22 0
14 37 40 12
18
0 12 28 4 (all in 1/100th mm)
(where there are more than 3 measurements in a line, that's the approx location of the max value)
Which implies I have roughly 0.2mm in the X rails, and 0.2mm / 0.3mm in the Y
It's quite possible that I can easily sort the X rails by loosening the rail mounts and seeing if the rails themselves deflect upwards when not held down (which would imply a bend in the right direction when tight). That I can fix by mending the mounts gently to eliminate nearly all the deflection. The Y rails are mounted differently, so I may leave them alone unless I have to.
But that's a job for tomorrow!
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
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So I thought about this, first, there's how flat is the bed? Then, does it move, ( yes, it's heated, it moves, but likely not "that much" ) then how straight are your rails and ...
Then I thought "this is what software compensation is for". You should be repeatable, the loads don't change that much, ( and the measurements are the same coming from either direction? your Z axis acts nice? - Hmm, another potential can of worms, there's likely some "shimmy" with Z motion that affects all 3 dimensions. )
Have fun,
Oh, occurs to me, if the bed isn't flat, a 4mm sheet of AL. would be easy to scrape in. ( But that's the machinist cutting back in. )
dave
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Wow, that is really neat!
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After the holidays it feels extremely difficult to get back to work. How do you motivate yourself to get back in?
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By looking at the bank balance.
"It is easy to decipher extraterrestrial signals after deciphering Javascript and VB6 themselves.", ISanti[ ^]
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On the same boat.
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You got a boat! Just retire and go exploring now.
"It is easy to decipher extraterrestrial signals after deciphering Javascript and VB6 themselves.", ISanti[ ^]
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They say that the happiest days of boat ownership are the day you buy it ... and the day you sell it.
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
AntiTwitter: @DalekDave is now a follower!
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"Whatever floats your boat" comes to mind.
"It is easy to decipher extraterrestrial signals after deciphering Javascript and VB6 themselves.", ISanti[ ^]
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That is true! Just sold ours...
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not just the bank balance, the other one also.
I'd rather be phishing!
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Well I got paid 2 days ago... so I just stare at my bank account for a few minutes until I remember why I need to work to earn money.
After that I am fully motivated and get straight on with... reading posts on here
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musefan wrote: reading posts on here
And consuming those valuable bits over Youtube.
"It is easy to decipher extraterrestrial signals after deciphering Javascript and VB6 themselves.", ISanti[ ^]
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Focus on the moments when the kids drove me crazy...
"The only place where Success comes before Work is in the dictionary." Vidal Sassoon, 1928 - 2012
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Getting back to work IS vacation.
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