ER32 Adapter(purchased)

[b4dyc]

Hi again,
freezing cold down the workshop :(
Here is a picture of the ``tool`` as for the register, then I dont know what it is seating on? I assume it is the flat face at the rear that is perpendicular to the spindle.


I tested the diameter size of the end that enters the spindle compared to my 3 jaw chuck and they were very close to being the same within 0.0005``
I popped the Er adapter on once, measured the ``high spot`` marked and then removed + replaced it again. Tested and it came back to the mark so i am thinking that the tool is registering right?
I tested my 3 jaw again and it was closer on the silver steel, just thrown in! Then i added the collet adapter to the free end and saw a lot of movement again.
Tested the runout at the taper end of the ER adapter and I think I am getting repeatable errors of .0085``
It seems that the 3 jaw has a fair bit of wobble when putting it on yet it does seem to be fairly accurate when seated home
There is a video of what was going on here - vvv


Apologies for the twat in the background (radio DJ)

[stevec]

(02-02-2013, 04:42 PM)DaveH Wrote: Just to confuse everyone - there can only really be one register.

DaveH

I don't know if I'm the only one but I'm certainly confused!

b4dyc, If your 3-jaw has the same "slop" going on and repeatedly gives the nice dial indicator reading on the "Silver Steel" rod. wereas the collet chuck does not, then I would have to conclude that the later is woefully inaccurate.
Unfortunately, I can't think of a viable way to rectify it other than making your own collet adapter on your own lathe.
Steve

[DaveH]

Andy,
It looks quite well made, so don't trash it yet.
It does seem that the ER chuck is using the flat face as a register, whereas your three jaw chuck is using a spigot ( for want of a better word) for a register.
Just to make it a bit clearer there is a spigot on your lathe nose spindle that locates into a recess on your 3 jaw chuck. The spigot and the recess are a very good fit so that when you tighten the chuck it registers between the spigot and the recess - this makes and keeps everything concentric. The flat face allows the item being screwed on, something to be tightened against.

Now there is a recess in your ER chuck but it seems to me that it does not register with the spigot on your lathe nose spindle.

DaveH

[b4dyc]

Had a little thought about using a coaxial indicator from the mill. Put a 2mt ground bar into the tailstock and put the coaxial into a collet.
The video shows it wobbling around a lot!
Not sure if this is even a reasonable test, but it shows around .004 runout and i had .0085 total deflection, so its in the ball park. Useless to me , but in the ball park

[DaveH]

(02-03-2013, 07:58 AM)b4dyc Wrote: Hi again,
freezing cold down the workshop :(

Yeah, I know what you mean its 84F / 29C in my workshop
So you send me some of your cold and I'll send you some of my hot

DaveH

[stevec]

There is something different about the way the chuck registers and the way the collet chuck does.

I would never recommend comparing inside measurements of a bore to outside measurements of a shaft/spindle with a vernier if any kind of precision is required.

I was thinking of you locating another Myford owner and taking your chucks over to do a test or two on his Myford but I really don't think there's anything wrong with your Spindle or 3-jaw. It just boils down to the collet chuck adapter.

[Highpower]

(02-03-2013, 09:46 AM)stevec Wrote: I would never recommend comparing inside measurements of a bore to outside measurements of a shaft/spindle with a vernier if any kind of precision is required.

I feel the same way. Going by the measurements shown in the video, the cylindrical section of the spindle measured 1.2485" while the bore of the adapter showed 1.2460"? If that were correct it wouldn't fit over the spindle.

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You also cannot use a co-ax indicator to make direct reading measurements. They are only good for showing changes relative to position. Slipping a shim under the tip of a short arm vs. a long arm in the indicator would give you totally different readings.

Andy, setting your camera down on a solid surface or tripod would go a long way in helping to see movements and measurements in your videos. The camera shake makes it hard to get a good look at what is going on.
Although even with the camera movement, you can still see the wobble in your adapter when it's spinning on the lathe.

Just in the way of research - try finding the high spot on the OD of your adapter when it's on the spindle and mark it. Loosen up the adapter and slip a piece of tissue paper between the lathe spindle collar and the flat of the spindle adapter at the high spot, and tighten it down again. What kind of run-out do you get then?

[f350ca]

I use callipers for inside measurements BUT they probably aren't accurate enough in this case to directly compare the bore of the adaptor to the dia of the spindle.
Chucking the silver steel in the three jaw and grabbing the free end with the collet chuck should show errors in alignment of the mount and the collet taper. To improve the test chuck a larger piece and turn the free end down to fit one of the collets. The turned end should show zero runout, when you mount the collet chuck to this runout at the end has to be error in either the collet or chuck. If the bore runs true the problem has to be with the fit of the mount. Turn the free end down to fit a smaller collet, if the error changes the collets may be at fault, if the error stays the same the chuck is at fault.

[EdK]

(02-03-2013, 11:14 AM)f350ca Wrote: I use callipers for inside measurements BUT they probably aren't accurate enough in this case to directly compare the bore of the adaptor to the dia of the spindle.
Chucking the silver steel in the three jaw and grabbing the free end with the collet chuck should show errors in alignment of the mount and the collet taper. To improve the test chuck a larger piece and turn the free end down to fit one of the collets. The turned end should show zero runout, when you mount the collet chuck to this runout at the end has to be error in either the collet or chuck. If the bore runs true the problem has to be with the fit of the mount. Turn the free end down to fit a smaller collet, if the error changes the collets may be at fault, if the error stays the same the chuck is at fault.

That's good advise.

Ed

[b4dyc]

Okay, I have spoken to the supplier and they have asked for it back so they can give me another. They do say that it should be within 0.0005 out of true and saw my videos and thinks something is wrong with the adapter.
They asked that I test the register first with some marking blue (used a lipstick ) and it had a lovely ring all the way around :) so I think my myford is good.
Lets see anyway *crosses fingers*