Custom collets

[Screwdriver]

I spent a lot of time <not working> on getting that sorted...

 

[Screwdriver]

You shouldn't be because some of the dims are quite obviously wrong.

Enlighten me.

 

[Pete.]

Enlighten me.

1/2" converted to 12.61mm

 

[Screwdriver]

I see so you predicted the fine measurement of 12.61mm should have been 1/2" which I only posted after your insult?

Sounds like sour grapes. What is your problem?

 

[Pete.]

It's not sour grapes, What on earth would I have to be sour about? The guy wants a spindle made so I looked at the drawing in metric and and it was clear right away that it had been poorly measured or converted, I didn't need your imperial drawing to see that. The age of that machine means it would be drawn in inches and fractions, or decimals where a fit was necessary. Very few of the metric dims convert directly to inch fractions so it stands to reason that it was either poorly measured or poorly converted.

Sorry if you feel insulted or offended but I'm hardly going to sit back and keep schtum when there's a chance that someone might use a poorly dimensioned drawing to produce the man a new spindle.

 

[Pete.]

It's slightly possible that the intended size of 0.5" could have been intentionally undersize and adjusted with a shim or two...

Or it's been subject to some wear.

There's not much to wear on a spindle that has no quill. The threads and the taper, possibly the keyslot. Everything else should measure exactly as it was made.

 

[Screwdriver]

It's not sour grapes, What on earth would I have to be sour about? The guy wants a spindle made so I looked at the drawing in metric and and it was clear right away that it had been poorly measured or converted, I didn't need your imperial drawing to see that. The age of that machine means it would be drawn in inches and fractions, or decimals where a fit was necessary. Very few of the metric dims convert directly to inch fractions so it stands to reason that it was either poorly measured or poorly converted.

Sorry if you feel insulted or offended but I'm hardly going to sit back and keep schtum when there's a chance that someone might use a poorly dimensioned drawing to produce the man a new spindle.

Well that's obviously nonsense. You looked at 12.61mm and it was "obviously wrong"? Rubbish. The 12.61mm is the precise figure, quite how you dare to suggest it must be wrong because it's nearly but not quite 1/2 inch I honestly don't know. You must be some sort of psychic. Predicting that it really should be 1/2 inch (which I posted later). The crude inch measurements are pretty much all wrong I should expect.

As are you.

 

[Pete.]

If you had ever looked at drawings of machine parts from that era you would know that they use fractional inches on all non-critical dims. This stuff was drawn on drawing boards not CAD and they followed a convention. Why would there be two shoulder dims of nearly-half-an-inch?

Fact is that you've now put up two drawings, one metric and one inch - and they don't agree with each other. They can't both be right.

 

[Freddy0309]

Additional - if I was to be making that sort of part and I was supplied with those figures, I would want the original part and/or the parts it fits to for verification purposes

For what it's worth the drawings are excellent and should be more then enough to get a quote but I would still send the original quill so they can take their own measurements and match a copy to the original. Although I'd need to get a couple of quotes to see if it's something I can afford to do straight away or if I need to look at modifying a collet chuck and make a drawbar

 

[Screwdriver]

Seized bottom bearing at some point in the past?

I'll stop clutching at straws in a minute

You should stop now. Pete is confusing the issue by insisting a correct figure of 12.61mm is "obviously wrong" when he is the one with no idea what he is talking about.

After his insult, I posted a second diagram which was the base drawing I used for building a model and THEN measuring. It is in fact the 1/2inch is not correct. Unless Pete is staring into a crystal ball, his insisting that 12.61mm is obviously wrong has no basis is logic and is factually incorrect. It was just a vehicle for him to support an unwarranted insult.

 

[Pete.]

Here's a drawing, drawn by a draftsman in the '70s.

 

[Screwdriver]

It's obviously wrong.

 

[Pete.]

It's obviously wrong.

No need to get childish, I was just putting it forward as an example of how stuff was drawn back then. To explain my initial reasoning. Non-critical dims are almost always fractions. Why would they do anything else?

 

[Screwdriver]

You started it.

 

[Pete.]

I pointed out what I saw was a mistake in the drawing. Stick it under a CMM and we'll all have a laugh at one of us.

 

[Screwdriver]

I pointed out what I saw was a mistake in the drawing. Stick it under a CMM and we'll all have a laugh at one of us.

Fine. You said it was "obviously wrong" before I posted the other drawing. I have deleted that to avoid any confusion or claims of psychic ability. What's "obviously wrong" with my drawing?

 

[Pete.]

You're the only one claiming phsychic ability, and the only one hurling actual insults. I've already said why I think the drawing was obviously wrong and now you've deleted the drawing that contradicted the one you've left up I don't see that there's much more for me to add. I'll leave you to your gainsay.

 

[Wendelspanswick]

Ding Ding round 2?

 

[Screwdriver]

You're the only one claiming phsychic ability, and the only one hurling actual insults. I've already said why I think the drawing was obviously wrong and now you've deleted the drawing that contradicted the one you've left up I don't see that there's much more for me to add. I'll leave you to your gainsay.

I have deleted it. It was confusing you.

You said the first drawing is "obviously wrong".

Explain.

 

[tinman123]

what size is the bore of the collet you do have freddy?
if it was big enough you could maybe get a ER collet set and modify the shank on one to suit, but it id want to be a decent enough in the one you have.