Thread: Taster, Arbors and Repeatability

Yeah I agree it sounds like it's a bad taper on the arbour. You might be able to re machine it and need to start again, but if you do machine it I doubt it will be true in the bore and will need re boring again.

You might need to put this one down to a good experiment of boring in the mill.

Dave

Originally Posted by Dave J

Yeah I agree it sounds like it's a bad taper on the arbor.
Dave

Dave - how can you say such a thing! That arbor cost all of around $10. I can imagine that the taper on a cheap $5 arbor might be out but not an expensive one like that!

Bob, it will be interesting to see the arbor once blued up. I guess the other possibility (although slight) is the hole that the Taster shaft mounts in. If there is a little clearance and the Taster is only secured with 1 grub screw there may be the possibility of some movement. Does wrapping tape around the taster shaft (that is, decreasing any clearance) make it better? I was impressed with the fit of the cutter that came in that arbor - you could feel the cushioning as the air behind it compressed.

Michael

Originally Posted by Dave J

You might need to put this one down to a good experiment of boring in the mill.

Just to disagree, I think it will be ok due to the adjustment on the taster. (once the arbor is fixed)

Could be worse, my spindle needs a grind..... I'll get around to it one of these days.

Stuart

The one positive thing about this little adventure is confirmation that the 50 year old spindle runs true. I was fearful that the 13's accuracy might have been in question. This will spur me on to commence work again on the table lowering plate. It's a prick of a thing when projects lose their momentum and sadly I have a few that have.

BT

Good luck with it Bob. My experience is that the blue may not tell you the whole story, it's too thick. If the blue doesn't reveal all, I've had more luck by cleaning it up and then looking at the witness marks on the taper. Mind you my experience is with the shallow morse tapers, so perhaps a faster taper like that may be easier to blue. But it's certainly the same thing with spindles, once you start getting down to it, witness marks are your guide. Are you marking the taper and spindle and placing it in the same location each time?

Pete

Hi Bob,
I'm wondering if the taper wasn't quite seated properly when you machined it?
As for the blue, if canode/marko is too thick, try a whiteboard marker. Once dry it is very easy to wipe off and much thinner than the spotting compound.

Cheers,
Ew

...and for really, really fine markings, try using the haze left behind after wiping with metho. I am told that's in the micron neighbourhood...

Originally Posted by Pete F

Good luck with it Bob. My experience is that the blue may not tell you the whole story, it's too thick. If the blue doesn't reveal all, I've had more luck by cleaning it up and then looking at the witness marks on the taper. Mind you my experience is with the shallow morse tapers, so perhaps a faster taper like that may be easier to blue. But it's certainly the same thing with spindles, once you start getting down to it, witness marks are your guide. Are you marking the taper and spindle and placing it in the same location each time?

Pete

The tool can only be installed in two positions 180 degrees apart due to the drive dogs (?) on the spindle Pete. I had been replacing the arbor in the same location. Given the soft, free machining nature of the arbor I'm now wondering if it might be a home made ring-in. The machining appears well executed though. It is puzzling.

This could simply end up being as Dave suggests, a demonstration of using the mill for turning. And as I indicated in our email discussion during the week, it was great to get back in the shed and make something even if it does turn out to be a near fruitless exercise.

Bob.

ps. Ew and Gregor, thank you for the suggestions. I often use an Artline permanent marker for marking out. The ink has a thickness that renders it useless for bluing but for testing rough fits it works well enough. I will obtain a whiteboard marker.

The metho haze will be kept in mind. I like it GQ.

Hi BT,
I'm not sure you need to worry about wafer thin blue just yet(though I'm sure you'll get there), you're chasing thous and tens of thous, not tenths.
I'm wondering if the tapers are even meeting. the arbor looks longer and looks to be deeper into the spindle. If it was a ding in the arbor, shouldn't you still get repeatability*? (as opposed to the taper angle be wrong)

Your dogs are part of the spindle?

Stuart

*repeatability better than 10 thou I mean

Integral Stu, A precleaned photo.

(The spindle is double ended, 30 taper one end, P20 taper the other, hence the draw bar sitting there)

I'll head up the shed now for hopefully a discovery session.

Originally Posted by Anorak Bob

The spindle is double ended, 30 taper one end, P20 taper the other

Well now isnt that clever! Why wasn't I informed? (I was about to make a crack about the drawbar going in from the other end)

Stuart

Originally Posted by Stustoys

Well now isnt that clever! Why wasn't I informed? (I was about to make a crack about the drawbar going in from the other end)

Stuart

A bit more about it here Stu should you desire to be informed - https://www.woodworkforums.com/f65/sc...0/#post1166884

Originally Posted by Anorak Bob

The tool can only be installed in two positions 180 degrees apart due to the drive dogs (?) on the spindle Pete. I had been replacing the arbor in the same location. Given the soft, free machining nature of the arbor I'm now wondering if it might be a home made ring-in. The machining appears well executed though. It is puzzling

Ah yes sorry, my brain really must be mush today. I was just picturing in my mind how I do my tapers. I can see the "ears" would be a bit of a PIA in some ways, as I was going to suggest carefully rolling it along a surface plate, but that ain't gunna work!

I don't think it will take much up in the spindle to throw it out at the tool end.

Hi BT,

You probably did this already, but check for burrs and dust or other contamination... inconsistency is usually down to not seating properly, did it blue consistently?

Regards
Ray