On 2010-05-21, Searcher7 wrote:
On May 20, 10:41*pm, GeoLane at PTD dot NET GeoLane at PTD dot NET
wrote:
[ ... ]
Yes. that's the screw. I assume it is there for a reason. It is
definitely not loose.
Also I have no problem putting on any of the included toolholders.
When I do, the range of the approximate 180 degree swing of the
locking bar becomes a 90 degree swing between locked and unlocked when
a toolholder is attached.
O.K. That is reasonable. But based on what you say later in
this article, I find myself wondering whether you have checked the
locking angle with the same holder in *both* stations.
But the genuine Aloris AXA12N toolholder I have will only fit on one
of the two sides. I thought it was because the locking bar was in the
way, which it is. But even when I open the wedge completely and then
unscrew the locking bar the Aloris toolholder still will not fit down
on that side. ?!?
This is why I ask about the locking angle for one of the
supplied holders tried in both stations. Normally, you should have the
same fit in both stations.
And when on the side it does fit on the swing distance of the locking
bar between locked and unlocked is only about 10 to 15 degrees.(Though
I don't know how important that is).
Given the starting angle, I consider it quite important, as the
lever will be over the tailstock -- and perhaps hitting a drill chuck or
live center mounted in it.
Ideally, the unlocked position should be something like 3:00
o'clock (parallel to the bed, pointing towards the tailstock end of the
bed), and the locked position should be with the lever pointing out at
the operator.
Milling the Aloris holder would increase that swing range and allow
the toolholder to fit on *both* sides *if* I unscrew the locking bar.
(Sigh).
And -- this would have to be repeated for every genuine Aloris
holder which you subsequently get -- and all of the better clones as
well.
Now -- if you get different locking angles for a supplied holder
depending on what station it is on, I believe that one of the wedges is
too far down.
If you have two lengths of round rod of the same diameter (e.g.
drill rod), set the lever in the fully locked position and try measuring
the width of the two dovetails. Do this using the rods as follows
(view with a fixed pitch font like Courier to avoid distortion):
______________
( ) \ / ( )
________\ /_______
(the rods should be bigger, but that is the biggest that I can show
using ASCII graphics.
Anyway -- place the rods into the Vs of the dovetails, and
measure the width across the outside of the rods (using a caliper or a
larger micrometer).
The measurement across the rods should be close to the same on
the two dovetails. If it is not so, then one of them is improperly set
on the threads.
Now -- just for the fun of it, do the same kind of measurement
*inside* the dovetails on both the supplied holders and the genuine
Aloris. I suspect that you will find a somewhat wider measurement on
the supplied holders based on your fit experiments.
None of the photos show your post from the needed angle. Look
at the toolpost diagonally from the corner between the two dovetails, so
you can see both wedges at the same time -- ideally with the viewpoint
at a level about half-way up the toolpost.
If you can easily see that one wedge is higher than the other,
you have one started on the wrong thread -- an assembly problem at the
factory. You *can* go back to the vendor and see if he can supply you
with a replacement one.
But what *I* personally would do is to disassemble the toolpost
to the point of removing the wedges (I described how to do this in an
earlier article today) and re-installing them so you get both starting
at the same time, and so the lever angle winds up more reasonable.
Note that if you do this, you will probably void the warranty,
so if this is important to you, try the vendor route first.
And if it turns out that the screw is not present in others, it
might be that the screw caused the wedges to be put in with this offset.
It might help to know how these work internally:
1) The lever turns a cylinder inside the body of the toolpost
which has a multi-start thread on its outside diameter.
2) The wedges have partial mating threads on the inside, so
when the lever turns the cylinder, the wedges move up and down.
3) The wedges move in contact with an angled surface which causes
them to increase or decrease the width of the dovetail as they
move down or up.
Since the thread is multi-start, it is possible to get the two
wedges started out of step, so one remains higher than the other. And
-- it is also possible to remove the wedges and re-start them so both
move at the same height.
If the wedges are not at different heights, but the dovetails
measure significantly different widths, the cure would be to use a
proper dovetail mill to narrow the one which is giving the problems.
This problem would *certainly* call for a vendor replacement as the
first approach.
And if it comes to a choice between a proper fit for the
supplied holders or a proper fit for the Genuine Aloris holders, I would
go for the latter as this would increase the number of holders available
through surplus and eBay channels.
Good Luck,
DoN.
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