Help with fixing Colchester Lathe power feed

[j_e_f_f_williams]

Hello,

Back story:  I have had a 1960's Colchester Dominion 13x36 for several years and as long as I have had it it has sometimes jumped out of powerfeed.  Over time it got a bit worse, I knew I had to look into it though time wasn't really available and I knew I was going to move the lathe.  So the lathe is in its new location and the other week it started popping out of powerfeed more than I wanted to deal with.

Problem:  So I took the powerfeed shaft out of the lathe and dropped out the sliding mechanism that does the powerfeed.  The flaw in the design is that the powerfeed shaft turns all the time and when powerfeed is not in use the shifter mechanism (where the issue is) hangs from it and gravity pulls it enough that the feed shaft slowly has eaten the CI hole to be oval.  See attached Image IMAG0067 to see oval of shaft hole and IMAGE0070 for where it is located on the lathe and how it just hangs there.

Proposed Solution:  I figured I will bore a larger hole (boring head on mill) located where the original should be and then create a bushing to relocate the shaft.

Question(s):
1.  What's the thoughts on bushing material for this?  I would obviously prefer to wear the bushing (can always make another) vs the feed shaft so I was thinking bronze.
2.  I have having trouble in figuring out a way to mount the casting on the mill to align and bore the hole.

Currently I have created a temp shaft with key way and used some shims to force the outer face of the gear against the inner face of the casting which should be the preferred location. Then I used the temp shaft in the gear to locate the hole location, see IMAG0074.  But there are no good reference locations to use to mount the item on the mill table and I have am having a tough time getting the shaft to be X & Y perpendicular to the table.

I am trying to add pictures of this so bare with me as this is also my first post to the forum.

Any thoughts welcome on how to proceed as I really miss my lathe powerfeed  And until I fix it I also don't have threading capability as my gear box is apart to get the powerfeed shaft out.

Pictures:  0069 shows shifter out of lathe.  0070 shows location on lathe at bottom of carriage, 0067 shows empty oval holes, 0074 shows my current setup to determine hole location, 0076 shows the oval around the temp shaft

Thanks, jeff

[mike os]

you have the same carrage as my student.... how do you get it off? do you have to take the feed & lead out first?

or can you get is out with just the feed shaft out?

[j_e_f_f_williams]

you have the same carrage as my student.... how do you get it off? do you have to take the feed & lead out first?

or can you get is out with just the feed shaft out?

Hello,

The part I have removed falls out once the feed shaft is removed.  
To remove the complete carriage I had the feed shaft and lead screw both removed.  
If all you want is the top of the carriage to be removed you can unbolt it from the side and then use long allen keys to undo the side plates that hold the carriage on the ways.  (pain in the you know where).  I have not done this and I think getting the allen key up past the gears on the side would be tricky but I can't see why it would not work.

The feed shaft can be removed without disturbing the gear box except I forgot about that option when I did it recently.  When I did it 2 years back getting it all back together was the hard part as you need to press the 2 balls for the feed 'clutch' into the socket and its a pain though I am sure there is some trick I don't know of.

And yes, the Dominion, Student and Master are similar/same machines just with different dimensions or gearbox as far as I know.

TTYL, Jeff

[DennisWA]

Jeff...

Although I have a Student, I can't help you, but you may have more luck with these sites, particularly the first:

http://groups.yahoo.com/group/ColchesterLathe-User/
http://www.practicalmachinist.com/ Try a search here
http://www.lathes.co.uk/colchester/page36.html

Cheers
Dennis

[j_e_f_f_williams]

Hello,

Just in case someone searches and finds this thread because they have a similar issue ... figure I will complete the story.

I e-mailed Clausings who took my serial number and sent the oldest manual they had where I then let them know what part (by ID in manual) I was trying to fix.  They then got out the original blueprints for the part and scanned in the section I was trying to fix and e-mailed me the scan as a PDF.  Once I knew where the reference surfaces were and the measurements it was time to mount the casting on the mill, locate the hole as per the drawing and bore away.  Made some bronze bushings and it's all back together and cutting fine.

As a side note there is a guy in Texas with spare parts for this lathe though he wants $600US for the casting so I measured several times before cutting as $600 was the next step if I screwed it up.

TTYL, Jeff

[mike os]

any chance of a copy of the manual jeff?

[DennisWA]

Jeff...Glad to read of your fix. You were lucky with the excellent response from Clausings! That is what I call service.

Cheers

Dennis

[DennisWA]

any chance of a copy of the manual jeff?

Mike..I can let you have a pdf copy of a Student manual (old roundtop version) which is 4.2Mb. If you want it, send me your e-mail address by PM so that I can send it directly to you.

Cheers

Dennis

[mike os]

Hi dennis, thanks for the offer...jeff has sent me his copy & finally I have the right one