Hello welcome to Enots engineering I'm Alan in today's video I have to sort a
problem out with my pedestal drill the Jacobs truck on the pedestal drill has
been running out since I've had it and I can never figure out what's wrong with it
So in this video I've decided to get to the bottom of it and try and fix the run-out
Let's go to the workshop and see how we do it.
with the spindle in the up position the run-out on a dowel held in the Jacobs Chuck is 0.4mm
this has got worse over the last few years
so I will strip the chuck out and see where the run-out coming from
I've held the Jacobs chuck on the tang in the vice
To remove the chuck from the Morse taper what I've done is I've
just got a nut and bolt put that down into the Chuck jaws tighten the Chuck
jaws up on the nut and with a socket turn the bolt
if it's tight or when you turn it won't come undone
just hit the bolt with a hammer to shock it and it should break the seal
Once you've removed the chuck the next thing I will to do is hold this in
a morse taper, because this centers been drilled out so I can't put it between centres
Check whether this taper is running true to the Morse taper or
whether it's the chuck that's been just poorly made and the taper on the inside
of the chuck is not running true to the jaws
here's a tip on this small taper the center hasn't got a tang on the end
so you can't use your drift to remove the center
so the way to get the center out is to just drop a nut in there
then you can put your drift on top of the center and extract it
that's a number 2 to 3 Morse taper I've checked the spindles clean so that fits
in there and that's the 2 Morse taper which holds the Jacobs chuck put that in there
make sure its in the next thing we need to do set a dial indicator up on here to see what the run-out is
I've put my magnetic base on the top slide with the dial indicator and
I'm just going to put this expanding mandrel in the headstock so I can turn the headstock
from the other side with the handle
I'll turn the headstock you can see the run out on that is 0.3mm which is
just over a thou so nothing like the run out when fitted in the pedestal drill
The next thing I need to do is see with the Chuck on there and a dowel held in the chuck jaws
whether it still runs out
Iv'e fitted the Jacobs Chuck to the spindle
put the dowel in so I'll check the run out on this you see now that dowel is
running out
0.07mm which is about 0.003" nothing like it was running out in the pedestal drill
so that's proved that the chuck is okay
I've put the chuck back in the pedestal drill and I'll just rotate it you can still see
the run-out so obviously there's a problem with a spindle on the pedestal drill
To remove the spindle undo this nut
on this side remove the washer take off the spring housing then on this machine I can pull
the handle and the gear out in one go hold the spindle because there's nothing
to hold that spindle from falling out that's the spindle this part goes
through the pulley at the top of the machine and the drive comes through the
spline on there a bearing in this end and a bearing in this end so what I want
to do now is see whether this spindle is running out to the outside I've just set
it up on the lathe what I've done is puts a V block on the top slide the
spindle and the quill in the V block mounted the dial indicator in a Jacob's
Chuck and I just want to check the run-out you see there it's running out
about 0.04mm which is about 0.0015" that's the play in it which is
about 0.05mm 0.002"so that seems to be okay
when I fit the Chuck in the spindle you can see the run-out I get on that dial indicator half a millimeter
so for some reason the chuck's not mounting up to the spindle correctly
I've checked the spindle run out on its own and that's running within a couple of thou
so something's wrong with the chuck and the spindle mounting
I've put some micrometer blue in the bore when I fit the chuck in you can see
it's only touching on the outer edge of the hole this end there are no marks at all
so it looks as if the Morse taper in the drill spindle is only touching on the front
that means when that goes in depending
on how this lies that the top bit lies it'll give you the run-out
let me explain they set up I've put a 4 jaw chuck on so I can centre this bearing diameter.
here and the other bearing diameter is just at the end here
because there are different diameters this diameter that diameter there's
another diameter here where the bearing goes and another diameter right on the
end I can't set my steady on this and then slide it along so I've clocked this
up true that's true as I can get it which is about 0.01mm 0.0005" something like that
this is the diameter where the bearing locates you can see
from that there it's doesn't locate on the back end because that's clear
it locates on the front end so I'll use the bearing diameter as the steady area
I'm moving the steadying in until the dial indicator moves
that's just touching nip up that one and do the other one the same again it's just touching there
lock up the top of the steady.
and lock that cap head
and the runout on the bearing diameter is
0.02 0.03 which is about 0.0015" check the run-out in the bore.
0.075mm which is 0.003"
okay - roughly set the taper what I've done is put a centre in the most taper that I wanted to machine
A revolving centre in the tailstock and a Morse taper between centers
so I can now come on to the Morse taper and move it across and roughly set the
compound slide to the correct angle
okay I've done the taper I found out what the problem was I'll show you
The problem was in the hole this slot here
What was happening with this morse taper
they hadn't gone deep enough on the hole I've just machined that deeper what was happening
this was hitting the end of the slot and still wobbling about at this thing like that
now I've machined a bit more out the back it's gone in further
it's gone up about another quarter of an inch.
they had just machined up to here so that last quarter of an inch wasn't deep enough
although it must have been very close but not close enough now that
and considering the chuck is running out about 0.003" I don't think that's too bad
well that's it for today thanks for watching and we'll see you next time
on Enots engineering