Mark Davison
Member
- Messages
- 160
- Location
- London
Inspired by Andy Pugh's CNC conversion of his Harrison Universal mill I embarked upon converting my Harrison vertical mill.
X Axis - This is where I started but I can't find the photos at the moment so they'll follow later.
Y Axis - I knew this was going to be tricky from readying Andy's account and looking at the photos. That said i the bits that caused me issues I didn't see coming. The main problem was the lack of length in the recess in the knee. The first ball nut that I bought was too long, luckily Zapp Automation has a 'special' froma cancelled order that proved to be just what I needed. The screw is a 1605. I went for a single piece screw (albeit made up of 2 piece permanently joined prior to installation. To make sure I could assemble the saddle onto the knee with leadscrew already in place, i machined a male taper on the nut carrier's spigot that mates with the a female taper that drops down through the hole in the saddle. I used the same angle as an ER collet.
You'll see from the photos that I had to take a die grinder to the inside of the recess in the knee casting. I have only 'cleaned it up' which removed just enough material to allow clearance around the ball nut carrier.
knee before i took the die grinder to it. The corrosion on the right hand side was there when I bough the machine. Coolant had got under the sliding plate the cover the recess and rusted up.
After the die grinder. I thing i had to attach both ends again after this to open up the corners a bit more.
Mock up of the carrier block for the thurst bearings. This is the original lead screw still. The two holes either side of the thrust bearing pockets are the attachment point for the original item. I drilled and tapped 3 new holes to take the weight of a NEMA34 stepper that now hang down on a plate from the the front of that block.
Machining up the front half of the new ball screw, This was EN8 round bar that glued and pinned to the 1605 screw to increase the diameter to take the thrust bearings. You'll see there was only just enough room for the bearing OD.
ball nut carrier. Width and depth were limited as i didn't want to remove material from the recess in the knee. This is before I decided to make the spigot in two pieces (male and female taper)
Turning the taper.
The female taper in place. I remade this about 15mm longer later on so it came right to the top of the corresponding locating hole in the saddle. I also cut a slot in each side to enable it to expand slightly in the locating hole to prevent any movement (it was a snug fit even before that).
X Axis - This is where I started but I can't find the photos at the moment so they'll follow later.
Y Axis - I knew this was going to be tricky from readying Andy's account and looking at the photos. That said i the bits that caused me issues I didn't see coming. The main problem was the lack of length in the recess in the knee. The first ball nut that I bought was too long, luckily Zapp Automation has a 'special' froma cancelled order that proved to be just what I needed. The screw is a 1605. I went for a single piece screw (albeit made up of 2 piece permanently joined prior to installation. To make sure I could assemble the saddle onto the knee with leadscrew already in place, i machined a male taper on the nut carrier's spigot that mates with the a female taper that drops down through the hole in the saddle. I used the same angle as an ER collet.
You'll see from the photos that I had to take a die grinder to the inside of the recess in the knee casting. I have only 'cleaned it up' which removed just enough material to allow clearance around the ball nut carrier.
knee before i took the die grinder to it. The corrosion on the right hand side was there when I bough the machine. Coolant had got under the sliding plate the cover the recess and rusted up.
After the die grinder. I thing i had to attach both ends again after this to open up the corners a bit more.
Mock up of the carrier block for the thurst bearings. This is the original lead screw still. The two holes either side of the thrust bearing pockets are the attachment point for the original item. I drilled and tapped 3 new holes to take the weight of a NEMA34 stepper that now hang down on a plate from the the front of that block.
Machining up the front half of the new ball screw, This was EN8 round bar that glued and pinned to the 1605 screw to increase the diameter to take the thrust bearings. You'll see there was only just enough room for the bearing OD.
ball nut carrier. Width and depth were limited as i didn't want to remove material from the recess in the knee. This is before I decided to make the spigot in two pieces (male and female taper)
Turning the taper.
The female taper in place. I remade this about 15mm longer later on so it came right to the top of the corresponding locating hole in the saddle. I also cut a slot in each side to enable it to expand slightly in the locating hole to prevent any movement (it was a snug fit even before that).