Hello welcome to Enots engineering I'm Alan
Today we use our tramming gauge which was made in previous videos to set the mill spindle true to the table
now this has not been changed since I had the machine
and I've decided its a good opportunity to check how accurate the machine was
when he was supplied
This mill trimming gauge consists of steel bar center spindle that's pressed in
dial indicator a bronze or brass bush that holds the indicator which is split
and on the end a cap head that clamps the indicator
now by inserting a bronze Bush or brass bush into the bar
when you clamp the indicator the bush will close onto the dal indicator and hopefully prevent damage to the indicator
so let's go to the workshop and see how we do it
tramming the mill is setting the spindle square to the table
and we do that by using this gauge all it is is a spindle and the distance between the dial indicator
and the centre it's enough to cover from the centre of the table to the edge of the table
so that you can get a full sweep with this on the table
so if you've got a wider table
This distance needs to be wider a narrower table you can bring that dial indicator in
I fitted the test bar into a ER 20 Collet held in the collet holder in the spindle
I've put two parallel strips across the table
one on each side and I've made sure there are no bumps or lumps on the parallel strips or the table
so what I'm doing now is I'm lowering the spindle
if you look at the clock on the right I'll just lower it till that clock goes to zero
this is in 0.0001"
so that's zero there
using a spanner on the draw bar at the top rotate the spindle around
Until it's parallel again with the table
if you look at that dial indicator it's not touching the parallel strip
What I'll do is lower the spindle I've set the spindle to zero
and I'll lower the spindle until the clock goes back to zero
just about there that's telling me that that's is 0.35mm out
so that means that this side of the table is 0.014" higher than this side
so I'll have to move the spindle about 0.007" to get them equal
and that's over a distance of 8 inches
now we need to adjust that to see if we can get it a lot better than 0.014"
on this side of the head you can see there's a nut there which you slacken off
so you can tilt the head
there's another nut just inside the castings under here to slacken off
on the other side it's just here
so that looks just over the thickness of the line just over zero
so I've undone the bolts and just tapped the head when you tighten the bolts up the dial indicator moves
so now I'll come down onto the parallel strip and get the clock to zero
set my spindle to zero
using a spinner on the top of the drawbar rotate the clock round
untill it's parallel
you can see that finger is past and that is now
it's about 0.0025" passed the zero over 8 inches
so before it was 0.014"
and now it's 0.025"
so when adjusting the mill the way I did it is
this is the thickest part the casting here this is hollow so I didn't do it on this part
I just put a block of wood on there with a rubber mallet just tap the wood
with the nuts slackened and just looking at the dial indicator
that's already on the machine bed you can tell when it moves
just tapped it there to move the dial indicator
so I could get the reading down to an acceptable level
once you've adjusted it with a spanner just put spanner on and make sure it's tight
on the three nuts to hold the head
turn the dial indicator around then until it touches the other side
Now that says the head is 0.001" over 8 inches out of square
so for 0.001" it's not worth messing about with it
I'll go back round again and just check that the other side is still zero
I've tighten the three nuts but the scale doesn't look as if it's moved
While I have the dial indicator in the machine I thought I'd just check the
Vice jaw run out so I've lowered the clock down onto the top of the back jaw
just found out if I remove the guard it still thinks the guards there
so we then let's the power on so now I can
now that's showing a run out of 0.0007" over the top of the rear jaw
and when you finished undo the nut
and remove the bar from the collet
well that's it for today
I hope that was interesting and hope to see you next time
On Enots engineering