Kondia FV-1 Head disassembly

[PixMan]

Wow! Great progress and looking fantastic.

Your photos don't show it, but I assume from your description that you did put the collar with the ball detent and spring onto the feed direction shaft and it's in the correct position. Given the variations of the dimensions given among the prints and original part, I was worried that heights of the counterbore on the bracket I'd made might throw the collar out of position (inward or outward) and be either loose or tight. If too loose you'll have to make a round shim for behind it, too tight would be easier to fix by taking a light facing cut off the back of the collar in your lathe.

My other big concern (as we discussed @ my shop) is the relative location of the Ø5mm engagement lever pivot. I see it on there so clearly you reamed that hole when you got to working on it. Does it actuate the clutch as it's supposed to?

[Mayhem]

Thanks Ken,

Yes, the hub locates perfectly and the detent has three distinct stops, as it should. I did indeed ream the pivot pin hole and the pin slipped right in. However, the lever doesn't actuate the plunger. The lever tip it too long, so I need to shorten it a little. Interestingly, the lever is a new one from Kondia, so I would have expected that the position of the pivot pin would suit this lever, given that the print for the feed trip bracket was obviously a revision of the one for my machine.

I'm not fussed at all and I know the feed trip bracket you made me is a massive improvement on the cast ones. I'm confident that I will have it working soon.

[PixMan]

I was just thinking about the Acme screw and nut set we made. Do you need to schedule a friend to come help with the installation of the knee onto the base? Does the new nut fit snugly into it's nesting place on the base?

It's going to be a delicate operation trying to get the thread started without damaging the thread start, given the size and weight of the components. I would advise putting a guide mark between the knee and the base as a "limit" when you get at least 1/2 the length of the nut engaged with the screw. That way you could avoid the kind of damage there was to the original by observing the marks if you ever needed to raise the knee very high. You could even put a steel block on each the base and knee that would act as a "mechanical limit" which would only be removed if it had to be disassembled again. (Though I'd hope you never have to do that.)

[Mayhem]

The plan is to hoist the knee up high and install the gibb and then lock it off to limit movement (weight still held by an engine lift) and then install the screw. Next the nut will be threaded on by hand and the whole assembly lowered into position. If need be, the knee can be loosened once the screw is fitted and lifted up to ensure adequate clearance.

I actually think the damage to the original nut was caused by the knee being cranked too high, so that the screw disengaged. There are threaded holes on the column that I believe are for stops but if they are not, I will certainly make sure that I fit some. I had thought about drilling and tapping a hole in the bottom of the screw so that I could attach a disc that would stop the screw being un- threaded from the nut. However, I wonder if this will limit my Z axis too much. What is the minimum length of thread that I should keep in the nut at any one time? My conservative guess would be 50% but I really don't know. My disc idea would see 100% of the nut being engaged with the screw at any one time.

I haven't actually tested the fit of the nut to the pedestal, as it is in my shop at my Mum's house, where it was part of my show and tell

[PixMan]

I'm not an engineer so I can't say with any authority just how much thread engagement is the minimum requirement. I won't let that stop me from throwing out an uninformed SWAG of 1.5x the diameter.

So for a 1-1/4" thread I'd say roughly no less than 1.875" engagement?

[wrustle]

Looks like things are coming together now for you Darren. Hope to see some projects being made in your machine soon!

Best Regards,
Russ

[DaveH]

(11-04-2014, 08:11 AM)PixMan Wrote: I'm not an engineer

Yes you are - you are a Machining Engineer par excellent

DaveH

[PixMan]

(11-04-2014, 05:06 PM)DaveH Wrote: Yes you are - you are a Machining Engineer par excellent

DaveH

While I appreciate the comment, I'm still just a machinist and not an engineer.

I can make a face like one though!

[EdK]

(11-06-2014, 07:56 PM)PixMan Wrote: ... I'm still just a machinist and not an engineer.

I can make a face like one though!

I'm neither. I'm a hack but I enjoy hacking and my face has always looked hacked so I guess I fit the mold.

Ed

[Mayhem]

OK.  I got a few hours yesterday to work on the mill.  First job was to put the parts back that I had disassembled in order to remove the selector shaft, which I toll with me to the US so that Ken and I could fix it.  Ken actually has the pictures of the repair job, which I will have to get from him, so I can post them here.


Putting it back together taught me a very important lesson: Don't remove the quill, without first removing the two screws that locate the quill skirt.  The result is torn off tabs  The good thing about this lesson is that I actually had two made up, as there was a minimum job cost when I had them made.

Once the head was back to where I had it previously, I decided to install the quill micrometer screw and the various parts that trigger the trip.  This is where I ran into some issues.    First, it became evident that the hole for the reverse trip ball lever cover screw had been drilled/threaded crooked, so that the screw had to be modified to stop it locking up the whole assembly.  The nipple at the end of the screw had to be turned off.

   
   

With this fixed, I turned my attention to the bottom lever, which looked like it had been flame cut and dropped into a bag and shipped as is!  The hole in it needed enlarging, as the hole in the head, through which the pivot it installed is drilled on an angle.  A lot of filing, sanding and colourful language got it to fit.  

   

I had to leave it there and there is a lot of work to do to get this section sorted out and working.  One thing I did note, it that Kondia have changed the design of their reverse ball trip lever.  The original one (as you may recall) had a small hole, with no threads, making its removal difficult.  The new one has a larger, threaded hole, the same as the Bridgeport ones.  Here you can see the new one on the left and the original (bent) one on the right: