HBM45 - head assembly - 1: Initial findings and considerations

oh i guess you have to torment yourself through a session with me as a teacher again or trying to be a teacher at least but i've drawn up a situation here where i have the as i have on the table there with the with the head casting here this is the granite the table precision table so i can put the the what i call the saddle piece here down on top of that this is scrape flat by the owner and then you have a and then to the dog tail which i will also prove inside here because this is now of course like this and you have a dog tail in here anyway and the head now has done these two flats here mating on the swivel plate so you can swivel this around there is no pin here that locates it so the actual position this way can well is of no great significance then to the position here but of course this way it has meaning that you have to line this spindle to the table which should be representing the column here then you put it that way and to do that i have extended the the spindle out it's then free fl floating you can see or is guided by the by the precision board here and i have it [Music] mounted and measured here and then compare it with what i measure here i find that they are a little bit unequal we've established that the swing plate here both on the saddle piece and the head is a little bit off but not really that much and then i will try to figure out the alignment between the spindle and the plate then here so in that direction it's not so critical because there is no as far as i can see no uh [Music] pin that aligns this specifically so you can tilt it either way really but of course in this direction now which is in the direction of the spindle you have to align it so one check then would be to find out just running across like this finding the highest point like that then going down here and finally the same height here but as you can see it's not touching it's not it's about how much is it uh seven hundredths of a millimeter of but then this is of course at this almost at the at least quite far out if i push upwards this is the amount of slop you have so um [Music] ideally we will rectify this by adding a sleeve here that you can mount here or this that's one idea ideally of course this should this bore should have been uh not so sloppy um but um to rectify this you could think that you could add the sleeve around here bolt it here and then either reducing the amount of throw you have on the spindle by adding the sleeve on top here or milling down whatever there will be a sort of a sleeve here which connects to the uh the scale but that's really just very very some millimeters so and it's not meant for that purpose either you could argue that you're not milling with the spindle when you're milling you should have the spindle probably in here so i'll just try to see if there is any slop at that point also which you see there is and then you can argue you have to lock down the spindle which is correct but still you have that uh amount of play because locking down wouldn't mean that you completely on all the circumference that you have complete as a fixture or fixing and even so you will have that uncertainty with you i think so i will try to measure now on the full length here on the inside on the actual casting to see where i should put this let's say alignment to the table here so the spindle and the column will ideally should be totally of course uh in line um but if the locking mechanism if you don't do anything here and the locking mechanism then throws this off by um some hundreds then i don't know if we should then keep it that way but i think so so my idea is i'm really thinking as i go now what to do i the point here i think we'll have to take the column to spindle um alignment as good as possible to the board that should be it uh meaning that you could try to alter that by uh scraping if this was linear or is linear um either by scraping here or here and here i mean on both sides of the castings here and i find that the if this now is flat to and then in alignment with the daltons which it seems to be after the owner having scraped it this is a little bit out of alignment but i think it was some 2 hundreds let's say three hundreds uh high or low like this and also a little bit like this uh but anyway i bolted it down so that now sits so you can't move so whatever area you have here is there and then to the table i just wanted to measure to the spindle finding this that's okay i can live with that or we can live with that or we can correct it but then i find that the [Music] uh the bore is quite sloppy so when extended i can move the spindle 20 hundreds minimum i think it's probably even more which is not good uh meaning that of course this will represent or will present itself in a in a out of uh round bore if you think about that not precisely line it can follow well you're not guaranteed a good result when building of course you wouldn't mill with the with the quill extended like this anyway but this would be i guess unacceptable because it would chatter and uh yeah it's it's not good so you're milling with the spindle in here of course and then of course also locked down which then i guess is not the biggest problem if you lock it down but how do you lock it down is it just with the with the with the screw on the side here which runs in this uh slot and you have one point then you will if you view the spindle like this you would press the spindle in towards one side of the board which is sloppy and then to decide okay if it was down there or if it moves up and down what alignment where does it meet i mean it would then be only be precise within alignment let's say i think it was four or five hundreds here so you would have that uncertainty anyway my thinking about this is that you could improve this design or let's say a little bit uh sloppy bore by um having a collar here so that you there there is room to to mount this collar here so either you move a little bit out here with the color that is precise of course you can locate that i think you can you can find out where what is absolutely zero or true and then use this this will of course then take away this this much uh throw so you could also then mail off this i guess flat and then probably either have a thicker or just have a the same here and you can actually also locate it a little bit inside here if you wanted to um at least then you would have a a fixed point here dead center that you could use and then of course locking it down will i guess fix this it's it's not i don't think it's the biggest problem if you think of it think of it as if you build you will use the spindle in here anyway and you will lock it down so it's permanently fixed but if you're trying to mill out here or if you bore well you have that kind of stop to live with it's a little bit rescued also by the by this uh there is a color here that amounts to this uh dial but you know that's not meant to be used as a as an alignment fixture and then of course you have the [Music] this thing that connects to the motor this is also help but in any case a little bit stop before so now i'm measured outside here on the spindle and i also remove the spindle altogether and measure with the [Music] inside the bore with the test indicator like this and i'm going a little bit in because i i'm meeting this hole that is machined for the rack feed do you indicate the setup sorry for the glare going into the hole finding the lowest spot so just the hundreds off so there there we are and then going in the hole you can go all the way down to where i see it's uh where you can see it at least there and then and down again you see i'm already like five hundreds of so that means that the column or the the head is tilting a bit [Music] let's see if i have a very this is a four sim here if i put the four shim underneath the column let me see now i put uh four hundreds of millimeter pair of shims you can see them down there in the front here okay moving again i guess it's hard for you to see but it shifted about two hundredths of a millimeter shame of course representing the inverse of what you have to scrape on the in this case the um the top side or the other side of the where you put the shim and of course then taking into account whatever area you have on the swing plate here with this purple plate here so [Music] if the dovetails match up with what we have on the underside here then i would rather take it on the swing plate i think it's better in addition uh to the fact that you can make this bridge piece here and uh secure you have a dead center you maybe you can make this like we have planned to make this namely with um the boar being a little bit offset not in center but a little bit offset just uh very much exaggerated but this means you can rotate the piece here around and then force the spindle in with whatever direction you want and then of course make locating pins or or screws maybe fixate it where you find it's the center and then bore out boring i was namely asked to to bore out this hole so that the this pinion rack pinion the gear shaft here could be uh moved up and down to get a more snug and precise fit so there he will make an elongated hole or no off-center hole so that he could turn this this big scale and around and then move this pinion up and down and this of course will help to secure a precise dislocated spindle without that much play so open up that hole to 50 millimeters so that we can make a boss here that you could use to off center and then force the pinion up so if you picked yourself this where the pinion rides in the uh on the rack here this fit was kind of sloppy and then the owner wants me to bore this hole bigger so that he can move this up because then if you pour out and then you can fit the sleeve instead of having that precise or this fit there you can fit a sleeve that is a little bit off center board thereby rotate it and you know tighten it but whether or not this will be directly i guess then opt-in and so that means that you will locate the spindle do this at this point and fixate it to whatever furthest point you have here what that would mean not sure but anyway it's very sloppy as it is now this quill uh no this um yeah the wheel with the rack and the the pinion here fit this will be much improved by this

Channel: Jan Sverre Haugjord

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Id: vW5U6uYifDk

Length: 17min 57sec (1077 seconds)

Published: Tue Sep 21 2021