Kondia FV-1 Head disassembly

[PixMan]

Given the inadequate engineering seen in other assemblies of your machine anything you can do to improve is time & money well spent.

You're getting so much closer to having a milling machine now, Darren! You must be getting excited.

[Mayhem]

I am Ken and I will have one of a kind! I'm contemplating drilling and tapping the bottom of the elevation screw and fitting a thick washer to prevent it from lifting out of the nut. It looks to me like the damage to the last nut was caused by the knee being raised up too high. The PO told me that he did a lot of drilling with the spindle parallel to the table.

[PixMan]

I'd also thought about that but there may be a time when you need just a little bit more height and it would be safe to raise it until you've got no less than 2/3rds of the nut's thread engaged. What I'd do then is calculate where the knee casting would be under that condition and simply put interfering blocks on the knee and column castings to stop it.

[Mayhem]

Actually, that would be fairly easy to do, as with the knee in the position it is in, I have room to do that.

[Mayhem]

Some pics of the difference in the bearing thickness, recessing the gear to offset the difference, and the tool I built to install the bearing and the elevation screw as one assembly.

New bearing (top) and old bearing (bottom).

   

Here you can see the difference in terms of the shaft length.  The bearing carrier should be flush with the top of the bearing.  

   

I could have turned down the corresponding amount of thread from the actual screw but there is a locating pin for the carrier that I would have to move as well and it wasn't worth the hassle.  Recessing the gear was a much simpler solution.

   
   

As usual, my 'special tools' are cobbled together from scrap bits laying about.  It was a bit of a challenge to find enough bits to incorporate the length of pipe with the outer diameter to ensure the outer race of the bearing is being driven into the casting.  Not pretty but it worked a charm  

   
   

Now that big heavy chunk of cast iron is back on the column and it is starting to look more like a mill.

   
   

I've still got to make a tin hat to cover the gears.

   

The most difficult part was plumbing the oiler.  The copper going from the oiler into the knee and the plastic line from the knee junction to the elevation nut were trashed.  Finding compression fittings for this size pipe has been difficult but I managed to find a coupler, which enabled me to connect the broken plastic line to the inlet of the junction in the knee.  

   

As I had to put a new oiler on, I managed to do away with the need for a junction on the side of the knee (oiler to junction, junction to knee and saddle).  I didn't have any of the armoured sleeving to cover the re-purposed plastic tubing, so I used a spring.  I'm pleased with the result.

   

I still have to fix up the line to the elevation nut, as the olive that fits the plastic line is too small for the metered oiler (it is an automotive oil gauge line).  Once that is done, I can pressure check the system and ensure that the metered oilers are not blocked.

[PixMan]

What great progress!

Please tell me you gave the elevation a couple of cranks and it felt smooth....or not?

[Mayhem]

Thanks Ken.

Given that the oiler isn't working just yet, I only turned the handle a few times after manually oiling the screw/nut. Going up it was very smooth. Going down it stepped a little but this is due to me not having set the gibs yet. It did the same thing when lowering it down with the engine hoist.

Also, I took your advice and marked the screw at the point where 2/3 of the screw was engaged in the nut (about 45mm). This corresponds with the top of the knee being flush with the top of the ways.

In the new year I think I am going to get one of the hydraulic shops to make me a short length of hose with the correct fittings to go from the knee to the elevation nut. Once I am happy that the metered oilers are working on the knee/nut I will then test the ones on the saddle.

Exciting times

[Mayhem]

Went out and gave the screw/nut an oil and cranked the handle.  It didn't want to move, so I double checked that the lock was off (which it was) and tried again.  Tried working it both up and down and was able to get some movement but it wasn't easy.  Then all of a sudden there was a loud crack, followed by a brief moment of panic and subsequent colourful language 

My concern was that perhaps I had broken the screw, or worse, cracked the casting.  I rigged up the engine hoist and unscrewed the elevation nut from the pedestal and lifted the knee with the hoist.  Once the nut was clear of the pedestal, I gave the handle another crank.  The problem remained.  However, I was pleased to have eliminated the screw/nut as the problem.

It then dawned upon me that the issue may be with the bearing retainer that bolts to the underside of the casting once the elevation screw has been installed.  As the bearing was thicker, it finished flush with the bottom of the casting, so I installed the retainer upside down, as it had a raised section that was required for the thinner bearing but would not allow a flush fit with the current bearing.  I stuck my head under the knee and saw a crack straight through the center of the retainer that confirmed my suspicion.  

Originally, the space between the bearing and the retainer had enough clearance for the bearing retainer.  With it installed upside down, it effectively locked down on the bearing carrier, causing the problem.  I had installed this after I tested the elevation nut/screw, which is why I reported no issues the other day.

Well, I have a lathe, so making a new retainer is no problem!  The old retainer. You can see where the bearing carrier has rubbed.

   

A suitable replacement found in the inventory.  Top left of this picture you can see the other side of the original retainer, with the boss that fits against the outer race of the bearing.  You can also see the crack!

   

Centre bored (oversize) to ensure that there is sufficient clearance for the carrier.  After the hole was bored, it was dunked in the de-rust tank, which is why the metal looks very different (I didn't bother with a facing cut).

   

Bolt holes drilled.

   

Painted and installed.  

   

[EdK]

Nice work Darren. That's the beauty of having machines to fix machines.

Ed

[stevec]

Not doubting or challenging Darren but, I don't see no crack?

Steve