I have a three part series on this modification:
9x20 cross slide dial Part 1
9x20 cross slide dial Part 2
9x20 cross slide dial Part 3
Taken apart:
In future, the spindle will be guided by two angular contact bearings which will be preloaded against each other. I expect a way better guidance and feel by that modification. And while I am working on the cross slide I will also make a new, bigger and better engraved dial with a vernier.
My design is based on drawings from G.H. Thomas, it is shown in his first Book, „The Model Engineers Workshop Manual“
The book is today a bit hard to get, I bought mine from Hemingwaykits:
This is my version of the design – I did it oldschool with pen on paper:
This chunk of free cutting mild steel is going to be the bearing block:
I didnot take much pictures turning the part, as its pretty straightforward:
The to be the vernier ring:
After boring and turning the first side, I put the part on the magnetic chuck to machine the second side parallel to the first side:
Measuring the thickness:
Of course I could not run the tool all the way against the magnetic chuck, so it left a thin ridge of material:
I removed that by flipping the part around once again and creating a roundover:
The drawing and material – again free cutting mild steel – for the dial:
Machined on the outside:
Parted off with the 2mm inserted parting blade:
And at this point I made a mistake – Instead of boring the dial to 10mm I went to 12mm.
I fixed that by opening the bore even more, up to 15mm and inserting a 15/10mm drill bushing. This mistake was in fact a lucky thing as the bore is now ground and hardened:
All the turned parts so far, the bearing block still needs a few holes drilled:
Drilling and counterboring the bearing block – I didn’t have a piloted counterbore of that size so I used the boring head:
There is a distance piece between the carriage of the lathe and the cross slide bearing. The holepattern in it didnt work out, so I plugged the holes with some roundstock that I glued in with Loctite 648 and redrilled/tapped the holes in their new position:
The cross slide screw needed to be extended – There was already a M6 thead in the end of the spindle that I could use for that:
The extension is just a piece of 15mm free cutting mild steel with an M6 thread in the end. Its fastened onto the screw with a piece of M6 threaded rod and a lot of Loctite 648:
As the cross slide screw is disassembled I had to change the top slide to 90° to act as a improvised cross slide:
Machined the extension and threaded it with a M12x1 fine thread:
Test fit, I will change the nut to a proper lockable nut (NOT a lock nut with the crappy nylon insert, that’s something for your bicycle not for a machine tool.):
Same test fit, just with the dial added:
And now for the locking mechanism of the dial, the end of the screw gets cross drilled and reamed:
All the parts of the locking mechanism – a 4mm steel ball from a bearing, a 4mm pushpin and a thumbscrew – The screw is just a placeholder until I machine a proper one:
Put together – The thumbscrew pushes the pin against the steel ball and that pushes the ball out of the cross hole against the bore of the dial (and locks it that way):
With the dial added, the end of the screw is still a bit long, I will cut that short later:
Setting up the rotary table with the indexing discs to engrave 200 lines (With 2mm pitch on the screw that gives me 0,02mm change on the diameter per division):
Setup on the engraving machine:
Engraving the lines, using a 90° pyramidshaped cutter:
Engraving the numbers:
Next is the ballhandle crank - Here roughed out:
Working all the spherical shapes with the ball turner:
Finished:
The pin on the end was sawn off:
Cleaning the sawn surface up with a file and emery cloth:
Then the handle was parted off, flipped around and cleaned up on the other side too:
Setup on the milling machine for drilling:
Spotfaced, drilled, reamed and countersunk:
Setup on a 10mm dowel pin to face the other side of the crank:
The handle was turned freehand with a graver:
Test fit:
The vernier was engraved:
Done:
The new bearings work great, the movement of the crossslide is way more sensitive and the new dial with its big diameter is very easy and accurate to read.