Colchester Triumph 2000 – Saddle Feedtrip

[Colin HeseltineParticipant @colinheseltine48622]

Need to pick a few brains on these machines.

I have the short bed version and my mate Tom has the long bed version and we have both just managed to source bedstops and the 5 position turret stop. In his case with the saddle moving towards the chuck and then hitting the bedstop the feed does not trip out and when testing it in screw cutting mode sheared the leadscrew shear pin. There is a knurled knob on the right hand side of the saddle which is supposed to adjust the trip out pressure. In his case this just keeps rotating. Looking at the drawings in the manual we think that possibly a small pin has sheared (was already broken).

I have not tested mine under power as yet but manually rotating the chuck the saddle pulled up to the stop but again did not drop out. The knob on my lathe does three complete revolutions from what should be lightest to firmest trip out pressure. What the manual does not say is which way to turn the knob to increase the trip pressure, so I do not know whether lathe is set to hardest or softest setting.

The other question is should this trip out work for both screw cutting and standard turning. The manual is not very helpful. Neither of us want to break anything so is there an easy way we can check what is happening without breaking gears etc.

Any help much appreciated.

Colin

[Colin HeseltineParticipant @colinheseltine48622]

[Brian GParticipant @briang]

Posted by Colin Heseltine on 11/02/2023 16:44:23:

…

The other question is should this trip out work for both screw cutting and standard turning. The manual is not very helpful. Neither of us want to break anything so is there an easy way we can check what is happening without breaking gears etc. …

Hi Colin

Looking at this parts list Colchester Triumph 2000 it appears that the tripshaft (P15) only operates on the apron gears and has no connection to the half-nuts (P13). This would make it work only on the feed, and not when screwcutting when you might want to keep the half-nuts engaged to cut non-standard threads.

Brian G

[DC31kParticipant @dc31k]

I would echo the above. The feed trip only works on the feeds (longitudinal and cross slide). It does not work with the leadscrew.

As stated above, the only way a trip would be useful on the screwcutting side is if it maintains synchronisation of the spindle and leadscrew (e.g. single tooth dog clutch).

The diagram on page 15 of the above manual (page 20 of the pdf file) is reasonably clear. Turning knob 56340-0 compresses or relaxes the 'clothes peg' 56540-0. This bears on spring 56820 which increases or decreases the force required to trip the mechanism.

One way to find out the direction is to determine the hand of the thread on part 56746. If it is standard RH thread, then clockwise rotation increases the trip force. If it is left hand thread, the opposite will be true.

Another way is to watch the 'clothes peg' as you rotate the knob. If it compresses, the trip force increases.

Edited By DC31k on 11/02/2023 18:10:26

[Colin HeseltineParticipant @colinheseltine48622]

I think we will get the bottom plate of Toms saddle and check the thread. Its that or drain remainder of oil from mine and stick the endoscope camera through the drain plug hole and take a look. Would like to start with the least pressure on the trip before test mine.

Colin

[Bdog507Participant @bdog507]

Good morning all.

I have a short bed Triumph 2000. On mine the more you turn the knob clockwise the more it increases the trip pressure.

Don't ask me how I know this, but when thread cutting towards the chuck make sure the bed stop is well away from the apron. For if the bed stop is clamped down and the apron touches it the lead screw lever will jam in the engaged position and you won't be able to stop or reverse he beggar fast enough!…….It cost me a new threading tool holder, and wrecked a rather expensive component that I had just spent an hour making!

However, if threading out from the chuck which is my preferred method, clamp the bed stop at your starting point and you'll be able to cut threads without the undercut that the tool requires when threading towards the chuck. Also if threading from a shoulder it looks far neater, and is of course stronger due to the lack of said undercut.

Cheers.

Stewart.

[Colin HeseltineParticipant @colinheseltine48622]

Stewart many thanks.

We did a test on Toms whilst testing screw cutting (without lathe tool in post) and yes it jammed and sheared the shearpin.

Useful hints.

Colin

[Bdog507Participant @bdog507]

Posted by Colin Heseltine on 19/02/2023 10:11:15:

Stewart many thanks.

We did a test on Toms whilst testing screw cutting (without lathe tool in post) and yes it jammed and sheared the shearpin.

Useful hints.

Colin

Well at least you won't do that again! (I know I won't).

When I bought my lathe some 15 years ago I got it cheap because the leadscrew wasn't turning. I took a chance and guessed it was the shear pin. So I called Colchester and they very kindly sent me a few FOC.

It's surprising how many parts they still keep for the older machines. A couple of years ago I had to rebuild the oil pump, and they still had the gasket and seal in stock.

Cheers.

Stewart.

[Colin HeseltineParticipant @colinheseltine48622]

It good to know they still have some spares for the older machines.

We put a brass shear pin in to play safe.

I guess i'll have to go and test mine

Colin

[Colin HeseltineParticipant @colinheseltine48622]

Hey It works. Tried with lathe running slowly and feedtrip knob turned fully anti-clockwise, kept hand on feed lever (just in case) and let it feed to stop. It halted quite happily. Turned feedtrip knob fully clockwise and tried again. Saddle hit the stop and lever dropped out correctly. The saddle bounced back about 1/8" from the stop.

We just need to sort out the feed on Toms lathe now.

Colin

[Bdog507Participant @bdog507]

Good show! Glad you've sorted it.

I use the bed stop on mine quite a lot, but have got into the habit of knocking the feed off manually just as it touches. If turning to a shoulder I advance the top slide a touch on the last pass & reverse the cross feed & back the tool out. This leaves a nice finish on the shoulder.

I'm often turning hard stuff like EN24, & the trip need to be wound in a fair bit on heavy cuts, or it'll trip halfway along.

Cheers.

Stewart.

[Colin HeseltineParticipant @colinheseltine48622]

Up to now I have stared at the DRO as coming up to a shoulder, but this means have have not got your eyes on the job. Hopefully with the micrometer bedstop I will actually be able to watch what the tool is doing. I'm sure manually knocking the lever out saves stress on the mechanism.

Colin

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