Modifying a Master Roundhead

[Bernard WrightParticipant @bernardwright25932]

I've had several problems with my Colchester Master cross-slide arise since fitting a DRO.

I noticed with disappointment the readout on the Y axis alter as it traversed under power.

I thought of incorporating a slide stop, after taking several steps to try and eliminate the movement, through minimising backlash on the feed screw and nipping up the taper turning arrangement, but discounted that idea as potentially damaging.

However, I stripped it down again this week, with the intention of eliminating the play in the thrust bearing, which is housed in the taper turning trunnion, by replacing the two magneto type open bearings, to a single double angular contact bearing in a new housing, I also did a few mods to the slideway to aid lubrication, by grinding grooves and cross drilling for oilers.

I've Cadded up an alternative trunnion housing to my satisfaction, and will proceed this coming week.

I'll post my progress with a few pics, I might do a YouTube collage of the photos to save space on this website…

Bernard

[Bernard WrightParticipant @bernardwright25932]

Cross-Slide conundrum

[Bernard WrightParticipant @bernardwright25932]

Added a small collage of pics of the proposed conversion and Cross-Slide prep..

**LINK**

Bernard

[Michael GilliganParticipant @michaelgilligan61133]

Nicely done, Bernard … I look forward to the progress reports.

MichaelG.

[Bernard WrightParticipant @bernardwright25932]

Thanks Michael.

Before embarking on this latest route of trying to get things how I want them now I've retired, I set about moving the Headstock over slightly to guarantee unsupported parallel turning, seems to have worked.

Then I moved the Drive Motor out of the base of the lathe to a position on the rear of the bed below the headstock.

The reason for this was to try and eliminate a vibration problem I posted about earlier, the drive belts were 78" long making the pulley centres about 3' apart, the belt wip generated by the VFD driven motor was of concern to me.

I'd almost eliminated most of the vibes but still wasn't happy, anyway I've cobbled together another YouTube photo collage…..

**LINK**

Bernard.

[Bernard WrightParticipant @bernardwright25932]

Made some progress on my Cross-slide mod.

Machined a new thrust bearing block, to fit in its carrier on the taper turning slide.

This new block houses a single Double Angular Contact bearing, as opposed to 2 open ballraces that require preload.

However, I've now eliminated that perceived play, but that mow highlights the wear in the cross-slide screw threads.

There is an anti-backlash adjustment, but when adjusted to near zero in one spot others are too tight.

So I'll have to make another leadscrew and nut in the near future, here's a couple of links to a photo slideshow of the various stages of progress…

**LINK**

**LINK**

Bernard

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