Lathe: checking for taper with new bed

[GrifterGuru]

Check taper by measuring with a mike.

Would that be a 6' 225lb Mike with brown hair per chance?? LOL

I get what you mean, just having a little fun is all

 

[dml66]

Check taper by measuring with a mike.

Great idea!

 

[dml66]

Using a Mitutoyo 0.0001" resolution digit (not digital) mic, I'm at 0.7871" diameter on the left side of the turn, 0.7869" on the right side, over 2".

That's good enough for what I do .

 

[GrifterGuru]

Two tenths over two inches? thats one tenth per inch. Not too bad.

 

[VicHobbyGuy]

Check taper by measuring with a mike.

Excellent point.
If the headstock was angled toward the operator, the workpiece held in the chuck would be tapered, but the distance of the closest side of the workpiece from the carriage and tool would be constant.
Similar situation exists when using tailstock offset to cut tapers.

 

[ddickey]

Using a Mitutoyo 0.0001" resolution digit (not digital) mic, I'm at 0.7871" diameter on the left side of the turn, 0.7869" on the right side, over 2".

That's good enough for what I do .

A smaller diameter on the right, or the tailstock end is not acceptable under any circumstance.

 

[SouthernChap]

A smaller diameter on the right, or the tailstock end is not acceptable under any circumstance.

Okay, it's possible I might have got the maths wrong here, and if I have, apologies, and if you're being ironic, well, use some emojiis, that's what they're there for.

If not though...

...don't be daft.

Now, I'll grant 0.0001" over an inch might not be adequate for some people. However, on a mini lathe, with for most people, a practical work envelope of at most 14" (and usually a fair bit less), that would mean a taper of about a thou and a half over the length of the maximum work envelope , which is likely to be fine for most work done on such a lathe.

But you're actually saying, for example, 0.0001" over 40" should be unacceptable to everyone or even 0.00005" (a teensy bit more than 1 micron) over 40".

Put it back in yer pants and stop willy-waving, mate!

 

[VicHobbyGuy]

A smaller diameter on the right, or the tailstock end is not acceptable under any circumstance.

I don't understand. Please explain why the direction of taper matters.

 

[SouthernChap]

I don't understand. Please explain why the direction of taper matters.

Fella was either doing what the kids used to call a 'weird flex'

Or he was being being ironic for humorous effect but forgot that an Internet forum post requires the use of emojiis to signal such an intent.

Or maybe he was being sarcastic, because, we were talking about a mini-lathe and to get into 'Proper Machinists heaven' one must of course, pour derision upon such distracting toys. (and yes that was irony!)

I dunno, all a bit weird really.

 

[ddickey]

@SouthernChap If you're testing your lathe for taper and it is cutting a smaller diameter on the tailstock end then that is unacceptable. If it is larger then there is a tolerance that is acceptable. I think it is .0005" over 10 inches but I'd have to check. Yes, a mini lathe im sure has different acceptable tolerances but cutting a smaller diameter on the TS end is not one of them I bet.