How precise is Haydn diagonal rods when assembled
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Thanks Doug that makes sense but I have 360mm arms and 300mm calipers, so what I wondered is whether there is a trick to measure something that is longer than the calipers? I could use the metal rod that protrudes from the caliper, but how to measure to high accuracy like this I don't know.
You couldn't unfortunately. Do you know any friendly engineering companies that may loan you a 350-375mm micrometer for a day
another way is that you could make a jig with a bit of timber (OR extrusion if your quick) set an end block up fixed at one end then a sliding but fixable block at the other locate an arm adjust the slider for a good fit. then using another block of say 100mm long in the gap measure with the inside jaws of your callipers add in the block length (Having first calibrated your callipers to allow for one ball) and you will have your rod length. -
I will have to get my 25mm micrometer out and start checking my balls now I have 18 extras.
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Its always recommended to check your balls from time to time (sorry I couldn't resist).
I do have a friendly engineering company nearby so I might pursue that option.
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Thank you for your kind offer but afraid it is impossible. I am in Russia.
Regarding to the measuring technique if you can make a simple jig I think it gives the same result as direct measuring with calipers assuming this is made accurately. You can't just get absolute value of the length but it is not relevant for the case. -
Hi,
I have these parts in three of my printers.
The bed calibration was spot on and and they print just fine.
You may have nothing to worry about.
Frederick
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Hi,
I have these parts in three of my printers.
The bed calibration was spot on and and they print just fine.
You may have nothing to worry about.
Frederick
Thank you for your response. Maybe 0.1mm is not a big difference indeed for Delta. But I am apt to get another set of ball studs. Anyway they can be used for making other heads, laser graver for example.
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Okay so I checked my balls (sorry)
Of the 6 spare ones I have not attached to a running printer
9.38mm x1
9.40mm x2
9.48mm x1
9.50mm x2I will check the other 12 that are currently deployed whenever I get chance, and then get the arms measured accurately, and see if a "perfect" combination can be found.
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Hi,
Haydn had these parts made - given his attention to detail I would not think he would be selling parts that did not perform as intended.
Ask him if you have doubts.
Frederick
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Okay so I checked my balls (sorry)
Of the 6 spare ones I have not attached to a running printer
9.38mm x1
9.40mm x2
9.48mm x1
9.50mm x2I will check the other 12 that are currently deployed whenever I get chance, and then get the arms measured accurately, and see if a "perfect" combination can be found.
I'll raise this with Haydn - looks like he may be making the arms to significantly closer tolerances than his supplier makes the ball studs.
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Hi Frederick,
I know they work and I know Haydn puts in a lot of effort to make the arms very precise.
But the balls are not that precise.
Personally I consider this an opportunity to match balls to arms to get even more precision.
I know he bought 1000 or so of the ball studs in a job lot. All he has to do if he can supply 6 rods exactly the same length is supply 12 balls of the same diameter. But since the rods will vary by up to 0.05mm maybe he would be willing to tape two balls to each rod to equalise the total length.
Simon.
Hi,
Haydn had these parts made - given his attention to detail I would not think he would be selling parts that did not perform as intended.
Ask him if you have doubts.
Frederick
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Okay so I checked my balls (sorry)
Of the 6 spare ones I have not attached to a running printer
9.38mm x1
9.40mm x2
9.48mm x1
9.50mm x2I will check the other 12 that are currently deployed whenever I get chance, and then get the arms measured accurately, and see if a "perfect" combination can be found.
I'll raise this with Haydn - looks like he may be making the arms to significantly closer tolerances than his supplier makes the ball studs.
Sure as I said earlier it's very marginal, and I suspect it will have almost no practical consequences, but then we go to extreme lengths for precision so measure your balls people!
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Come to think of it, is it diameter we need to be measuring alone, or distance from the mounting face of the ball stud to the end of the ball?
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Well IMHO what we should really be measuring is probably not possible without Laboratory equipment and that is the distance from the rotational centre of the ball and the mating face to the rod end spherically God knows how you would do that tho.
Doug
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Come to think of it, is it diameter we need to be measuring alone, or distance from the mounting face of the ball stud to the end of the ball?
It depends on how Haydn measures the length specified. If he makes it in a special jig with etalon ball studs then we can be sure this length accounts for an imperfection in end cup mating surface. If the length of rod is measured itself and specified length is derived from it then we forced to rely on fabrication precision. For first case we can get get the length difference for some deviation of the ball diameter dD as
dL = dD/2 * 1.85 for each ball. ( 0.85 is approximation for the derivative of the length from mating surface to the center of ball vs ball diameter).
For second case if a fabrication tolerance is precise we get the same result. If not it would be another story. Anyway it relates only to the absolute length. If we are interested only in relative match of lengths I think that thing would be simpler: the same ball diameters give approximately the same lengths.
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Well IMHO what we should really be measuring is probably not possible without Laboratory equipment and that is the distance from the rotational centre of the ball and the mating face to the rod end spherically God knows how you would do that tho.
Doug
And the distance from the ball centre to the carriage or effector it is attached to. Since this seems to vary also.
This is getting more like a physics problem now.
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When you order just the rod ends from Haydn, to make your own custom length rods, he does include a couple of his ball studs to make a jig.
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When you order just the rod ends from Haydn, to make your own custom length rods, he does include a couple of his ball studs to make a jig.
You can use the ball studs you have and match the length for final assembly that would be a perfect case for you in some sense.
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Well IMHO what we should really be measuring is probably not possible without Laboratory equipment and that is the distance from the rotational centre of the ball and the mating face to the rod end spherically God knows how you would do that tho.
Doug
And the distance from the ball centre to the carriage or effector it is attached to. Since this seems to vary also.
This is getting more like a physics problem now.
So many imperfections in the world! Excuse me for initiating such a lengthy discussion that may turn out as a full trash from practical point of view.
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Thats the most interesting sort of discussion.
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Thanks for your support! BTW how can i include smiles in posts?
