Damn disapointed

[Ueee]

I thought they were supposed to taper the other way, so there is less chance of the t/s moving backwards under heavy drilling loads. The mars and leblond are both thicker at the right end.

Ew

[nearnexus]

I just measured the CQ9325 and there's 0.65 mm difference between ends of the bed - tailstock ways.

Thicker at the headstock as Chris suggested.

I also measured the carriage ways and they were absolutely identical at both ends - pretty impressive machining.

I used my Mitutoyo mike to measure.

Rob

[cba_melbourne]

- Step drilling into something like brass will try to bind and violently pull the drill with tailstock towards the chuck. If the bed taper tightens towards the chuck, the TS cannot move and the chuck arbor will simply pop loose of the TS barrel and let the chuck/drill spin, with no damage done. But if there is a reverse bed taper, both workpiece and tool will be damaged as the drill with TS is pulled in.
- If the saddle accidentally collides under power feed with the TS, the TS will simply slide to the right. But if there is a reverse taper, the TS will bind up and something WILL have to break.

I just checked and admit there is no note in Schlesingers "testing machine tools" about this taper, since it does not affect accuracy. Nor is this taper mentioned in any inspection record. So I may have been wrong to say a reverse taper is to be considered a defect. An excessive taper however is certainly a defect, if it will makes it impossible to clamp a camlock tailstock at any random position along the bed. And it is at least a great annoyance on tailstocks using a spanner to tighten, because depending on position along the bed it will be necessary to reposition the spanner. Chris