Originally Posted by
phomann
OK, I think I understand how they are doing the leadscrew alignment.
Attached is an image of the base where Y-axis bearing mount attaches. As can be seen there are the 2 threaded holes for the mounting bolts. There are also 2 holes that alignment pins are mounted into. You can see that on the 2nd image.
I believe that the bearing mounting plate is nudged around until the bearing block, leadscrew and nut are aligned. Then the bearing block is tightened and then the holes for the alignment pins are manually drilled and the pins inserted. If you look at the pins and holes, they are not symmetrical.
I should be able to do the same, drilling new alignment pin holes. Or, maybe the pins aren't needed?
Cheers,
Peter.
Your exactly right about the order/proccess for installing new pins. Infact not being symetrical may even have some benifits in stability ( but maybe not, but its not important). One thing the none symetrical pattern of pins does do is help you to know which end plate goes in which possition. With a odd pattern there is no question as to where each piece goes.
I would add the pins after making your alignment. Bolts work loose to easy and flex/slipping happens very easy. Thats not to say that with carefull alignment and tightening of the bolts it will not hold as needed, but if it did move just a tick and this was not enough movement so that it was noticed by the operator
then the screws/parts would be getting used while out of alignment. Ofcourse this could accelerate wear, and even cause possible problems with the accuracy which may not get noticed until something is warn, or after a 1000 parts where made incorrectly.
So in simple terms it is just much safer, plus anytime you tear the machine apart it will go back together much easier/faster. This is the way you want the machine, this way its an easy job to jump in and do inspections or ajustments. You will be more willing to do so if its easier. And anyway, its not hard to drill a couple of anywhere you want them holes for the pins. A tappered reamer for the pin size will be needed, but these are cheap. Plus once you get in the habit of using pins on assymblies they will hold up better (other parts/projects). I like the pins with a center hole drilled and tapped for using a screw/slide hammer to pull them back out when needed, another "it makes it easier" in the end kinda thing when it comes time to dissasemble the parts.
Jess
GOD Bless, and prayers for all.