Hi all,
I have finally got around to re-arranging the workshop with my M250 mounted on proper feet, levelled and have taken a first cut to see how it performs.
Dia 40 mm black MS bar in the 4-jaw with 100 mm protruding and unsupported.
A worn tangential HSS tool without coolant at 240 RPM with 0.1 cut at 0.07 feed.
I had planned to machine a boss at either end, then change tools, add coolant and do a final finishing cut on just the bosses to assess the parrellism.
But the finish was much better than expected, so I just measured what I had - 0.05 over 100 mm taper with the outboard end smaller.
My understanding is that such a taper means the headstock needs to be rotated on the bedways.
I won't be doing anything about the problem anytime soon as a negative taper is in the correct direction when checking bearing fits.
Can anyone comment on:
- my diagnosis,
- taper not excessive for typical ball bearing fits,
- and how a similar problem was corrected?
Happy machining for the season,
John.
I have finally got around to re-arranging the workshop with my M250 mounted on proper feet, levelled and have taken a first cut to see how it performs.
Dia 40 mm black MS bar in the 4-jaw with 100 mm protruding and unsupported.
A worn tangential HSS tool without coolant at 240 RPM with 0.1 cut at 0.07 feed.
I had planned to machine a boss at either end, then change tools, add coolant and do a final finishing cut on just the bosses to assess the parrellism.
But the finish was much better than expected, so I just measured what I had - 0.05 over 100 mm taper with the outboard end smaller.
My understanding is that such a taper means the headstock needs to be rotated on the bedways.
I won't be doing anything about the problem anytime soon as a negative taper is in the correct direction when checking bearing fits.
Can anyone comment on:
- my diagnosis,
- taper not excessive for typical ball bearing fits,
- and how a similar problem was corrected?
Happy machining for the season,
John.
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