Hello welcome to Enots engineering I'm Alan
Last week I visited the Doncaster model engineering show and came away
with a bargain I'll show you that later I also had a parcel of aluminium
some plate aluminium cut to sizes that I asked for because I decided to remake my rotary head
which I used on the lathe and on the CNC machine and now I want to make it to be used on the milling machine
But being made out of MDF its's not strong enough to be clamped down to the table
and give a good hold without the MDF crushing
So lets go into the work shop and see how we do it
Last week I went to the Doncaster model engineering exhibition at the Doncaster racecourse
and I purchased a micrometer this one a standard More a Wright metric
and that cost me £5
this box is a rotary head dividing head whatever you want to call it
It's electronic, this end is just a protector. The thread on here and the spindle on here
matches the Boxford lathe so it's got the same thread as the lathe I think that's one and a half diameter register
Number 3 Morse taper in the end
so all the equipment I have for my Boxford regarding chucks 3 jaw chuck
four jaw chuck collets will all fit onto this the only thing I need to
adjust for a collet is the length of the drawbar for holding the collet into the spindle
So this one I made about three years ago four years it was a
experimental one so it was made in MDF copied the lathe spindle because that
gives advantage's I'm not having to purchase other parts
on the end there you see electrical connection on the end of the spindle so if I take this out
this is just a small extension to the cable so I can remove the back
completely the back is just got the socket for the motor
so inside here we have a toothed pulley two toothed pulleys and a toothed belt and this is a tensioning
device which came of a car cam belt adjuster that's just been modified to do this
I thought this sort of dividing head would come in handy
but obviously for a mill MDF is not strong enough to clamp down
so if I'm machining steel a bit more force on it so I've decided to remake this in aluminium
and add a few more features on it the first one being I found that
having the plug on the bottom was a disadvantage because this head if
you look at the spindle it's offset this was made for the lathe so I could clamp it to the
cross slide and then by moving it on the correct side and clamping it down
It would put the chuck in line with the headstock on the lathe it will come in handy on mill as well
and I'll make virtually a replica of this but being in aluminium
I don't need 20 mil thick sides I could get away with 10 and that means
it'd be slightly smaller so what we have is a spindle and the bearing on this end
spindle goes straight through to here we've got two nuts and a toothed pulley
there and the motor stepper motor is located inside the only thing holding
the front panel inside here is the pressure between the two bearings to
hold the spindle the first job is to take this apart just put some four mill
drills in the hole and put the drill in there to lock the spindle
it's not tight and now I can remove this
Now this is on a cam so as I turn the cam you can see the belt has come loose
I can take this out completely
this is just a bearing with an offset hole so as you turn this round it pulls the bearing
in and out tightens the belt up
that's the belt
This hole at the back here goes through in to the hole where the grub screws are
the grub screws are on the other side of the pulley
so if I take the two grub screws off
slacken them off
there's a grub screws right on the edge
So now the spindle will come out through the front
A hole in that locks it
see it's just a bearing recessed and the front board
The stepper motor inside
a cable
the other pulley that matches the first one
these blocks stop the bearing pulling through the board
being MDF if there's nothing behind there and you put force on the bearing to pull it in
it would just go into the hole
But with these blocks it gives it something to stop butt up against and stops it crushing the MDF
the stepper motor has a part number on there
It's a 3.1 Nm motor
the bearings SKF bearings I purchase bearings that have a seal
so any dirt and bits doesn't get into the bearing
A parcels arrived
this is the plate aluminium for the replacement
Two pieces for top and bottom
Two pieces for the two sides
they're all 10mm thick aluminium
two pieces that are 15mm thick
I've just noticed outside that the blue tits are back in the nest box this is the second year they've returned
it shows we are well into spring now
I've put some parallel strips on the table and these strips are to hold the plate off the table
so I can go below the edge of the material without cutting into the table
I'm putting the long edge onto the outside of the table like that
I will clock this edge up true and then I'll machine this edge to give a better finish
and then I'll move to the back of the table and machine that edge while
this is still held in position so I have two edges that are parallel
Now what I've done is I've moved the cutter from the front of the workpiece
and gone to the back I know this front edge is parallel
to the table so now I will machine the back edge and do exactly the same with a 5mm x 5mm cut out on the end
I've machined the back and the front
Now I will turn it round and square up the other two ends
When I've done that on the four plates that make the outsides of the box
I can then start to machine the slots across for the dividers
I'm clocking this side up to zero so I know it's true to the machine axis
Then I will machine this face to get a better finish than the sawn off piece
and put a 15mm wide slot in there The same as this 5mm deep but 15mm wide
For the end piece
This is the first plate that I've nearly finished it just needs the back part finishing
I've done the front and the two sides and I've machined the 15mm slot at the end
and another 15mm slot in the middle
and the way they slot in together
I will show you with the plate that's half done
That fits in to the other piece like that
and then when I've milled a 15mm slot up this side and level with the one in the middle.
This 15mm thick piece will fit will fit into there
and one in the middle so each side interlocks with the other side
Then to hold them together all I will do is screw through the side
One screw in each side holding the 15mm piece
and then the compression on the bearings pulling the spindle in one the back plate here will hold it in possition
and then the back door will just be a push fit in.
I'm coming along quite well with that
If I show you on the prototype
The 15mm slot will be all the way around you can see in the corner down here
they interlock and then the spindle front face panel just goes in
and then the bearing when it pulls from the other side pulls that panel in
And on the other side this is a fixed panel its got a slot all the way around and It can't move backwards or forwards.
So the two bearings tighten up on each other compress the box together
And then the door on the back just goes in to keep the dirt out
Well thats it for today hope thats interesting and hope to see you next time on
Enots engineering