On 2008-03-13, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:
[ ... ]
Surface grinders can be had around here for reasonable money, but no
place to put one.
Mine is a 4x8" one (or is it 4x6" -- a benchtop one made by
Sanford (now out of business but in business when I got the grinder, so
I got perhaps the last set of manuals from them before they went under.
What is the footprint and weight?
Without going down to measure it I'll try to work by memory.
Width of the base is about 12" (with the table overhanging
each side by about 8" at the extremes of travel).
Front to back is probably around 24" because the motor is behind
the base with a flat belt running up to the spindle. This design keeps
the center of gravity lower.
Height is probably about 24" with the vertical handwheel on the
top.
Weight? Never measured it, but it was just possible for me to
lift and carry it from the back of a SUV with the X-axis table set aside
and rejoined with it after moving. There is no way I could have lifted
it from sitting on the ground, but the SUV kept it at just about the
right height, and it took only a couple of niches of lifting to get it
on the workbench.
Hmm ... I do have the manuals scanned somewhere.
O.K.:
Dimensions: 20x24x22-1/2H
Net Weight: Approx 160 pounds
It has an electro-magnetic chuck, powered from a circuit in the
base (which I had to re-design for more modern parts).
If you want to see the manual, flyers and quote sheets:
http://www.d-and-d.com/misc/MANUALS/...NGS/index.html
or
http://www2.d-and-d.com/misc/MANUALS...NGS/index.html
[ ... ]
It was *because* mine was supplied with a bed turret that almost
all of the wear was on the cross-slide -- under power feed to part off
parts formed by the turret tooling.
OK. Different histories.
Yep.
Ahh. Interestingly, the Dorian Tool catalog of toolposts has an
annotated drawing of a lathe naming the various parts of said lathe.
And what names do *they* use? I don't have that catalog.
Moving up from the bed ways, the items are called the cross-slide and
the compound respectively. Same as your terminology.
Good!
Yes. But my underlying point is that Dorian felt compelled to devote a
catalog page to a drawing naming the parts of a lathe.
You have the catalog -- does it list the company URL? I got
something about opera when I did my first guess. :-)
I'm going to Aloris as well.
The better way for almost everything. Unless you get to one of
those really expensive toolposts which let the tool holders lock at 15
degree intervals. :-)
Like the MultiFix.
Yes. I never seem to remember the name of that one. If I had
one, I would be searching for more tool holders on eBay, so I would have
the name refreshed easily.
And the bank account depleted regularly. Not that Aloris is so cheap.
I wonder who handles MultiFix ()and QuickFix) in the US, if anybody.
Google didn't say. I assume that these toolposts are still made. Not
that I will buy one soon, but some iron porn is in order.
Well ... I know that Enco *used* to handle them -- back around
the early 1970s. Since I don't have the current catalog, I don't know
for sure.
O.K. Here is one in the USA.
http://www.emachinetool.com/accessor...onFamilyID=296
It looks as though size 'E' (200-400mm swing) or 'C' (300-500mm
swing) will fit our machines. They only list a price for the size 'C'
set:
$799.00 Post, three standard holders and one "Vee" holder. Hmm
.... they are shipped from Canada, so US duty will be added to the charge.
[ ... ]
Interesting. Why 16N versus plain 16?
Simple -- with the plain 16, you have to use inserts which have
a relief angle ground on them. With the 16N, the relief is formed from
right-angle edges by tilting the insert to provide the negative rake.
When used with inserts with the proper chipbreaker groove, it is in
effect cutting with a positive rake, even though the insert is held in a
negative rake position. Since the edge of the insert is square to the
plane of the insert, it can have a chipbreaker groove on each side, so
the triangular insert can provide six working points, instead of three
-- you use the first three, then you flip it over to use the second
three. At the price of good inserts, this is a worthwhile saving.
Plus, it will let me try true negative rake inserts some of these days
to see how they do in my machine.
Ahh. What inserts (make and model) do you prefer, and why?
Hmm ... I started with 200 of the TNMG 322 style and size by
"BAiLDONiT" (their capitalization, not mine) with the numbers:
S30S TNMB 160306
Q8819 G5 TNMB 322
on the label, but I picked up a couple of sets of a newer style from a
MSC sales flyer:
07080062 (MSC part number)
TNMG-322 C6 TiN
TMNG-322 NN60
Carbide Turning Inserts
on the top label, and
TNMB-322A-NN60
11/04 LB
153721 10
on the end of the box.
These seem to last longer before rotating to a new tip, but it
may mean that the older ones were optimized for a different workpiece
material, and the ones from MSC are better for the general run of what I
cut.
The older ones are 0.1245" thick, and the newer are 0.129"
thick, not enough to make much difference. But the newer ones *are* TiN
coated, which means less wear from abrasive materials.
BTW While I was down there I checked the bearings of the DuMore
toolpost grinder, and find that my relubrication of the bearings
seems to be holding up nicely.
And -- I was *already* using negative inserts with the positive
chipbreaker groove (and had 200 of them) with previous tooling, two of
them straight ahead, which provide two equal angles on either side of the
tip making them good for beveling edges, and one each of the right and
left turning holders, which have been mostly retired with the 16N tool
holder, which holds two inserts -- one for turning, and one for facing,
with a single common height adjustment working for both.
The lesson here is that the added flexibility of the #22 isn't proving
worthwhile to you.
Right -- but that is, at least in part, because of the presence
of the straight-ahead insert holders which provide some of the angles
which I would otherwise get from the #22. If I did not have those, I
might go for a #22 to add to the collection of holders.
The BXA-22 strikes me as disturbing the indexing of the tool
every time you change its angle, which negates one of the major benefits
of the quick-change toolpost -- that each time you replace the tool, it
in precisely the same position, so when you are making a production run
on something which requires multiple tools you can keep using the same
readings on the dials or on a DRO or dial indicators mounted to display
cross-slide position.
I bet the BXA-22 repeats pretty well, but it cannot be so good as a
block of steel. Nor can it be as rigid.
And in particular if you are loosening the clamp screw and
changing the insert angle frequently.
My thinking was that there are lots of things I will need to do only
rarely, so a fiddly but flexible tool does have a place. But your
experience with the 16N implies that the added flexibility is not
necessary.
Remember -- I do have the two straight-ahead holders in BXA-1
blocks -- one mounted for turning, one for boring, so I get 30 and 60
degree edges from those without rotating the toolpost, so I can keep it
locked square to the axis. If you don't luck into those, you may want
the #22 just for those operations -- mostly beveling.
[ ... ]
I've thought of that, but I have lots of tools with cylindrical shanks,
especially boring bars.
Well ... there is a holder specifically for the larger boring
bars. The BXA size has a 1" bore, plus a sleeve to reduce it to the
next size down.
I did buy a Dorian #36 (same as Aloris 5C). It does work, holding
round-shank boring bars quite securely. The only worry is that the BXA
#36 (5C) toolholder is quite large, reducing vertical adjustability. I
don't yet know if this is going to be a real problem.
Hmm ... can you position the T-nut so the block hangs past the
edge of the compound T-slot block?
[ ... ]
I did get a BXA-2, and have used it with a 0.5" round-shank boring bar.
It worked quite well, but does scar the bar shank.
The V -- or the setscrews?
[ ... ]
I already can see the need for multiple #1 or #2 holders. Is there any
reason not to have only #2 holders?
Well ... I have a mix because of what comes up at good prices
used. Otherwise, I would not care, unless I was trying to use a 1/4"
HSS lathe tool, in which case the 'V' might be a problem.
I hadn't thought about BXA-13. I'll look into it.
It is worthwhile when you need more reach without sacrificing
rigidity -- such as when threading something near the live center end.
Without it, I've had the toolpost hit the bulge of the live center.
Of course, a right-hand side dovetail would also deal with that
nicely.
[ ... ]
BTW -- I note that the BXA-4 does not specify how far the
centerline of the bore is from the dovetail, so the are not promising
that you could use a set of them as a replacement for a turret. :-)
Right. Aloris' turret replacement is the "Indexable" line.
Well ... that is their replacement for a turret *toolpost*, not
for a bed turret which is what I was talking about. Set the cross-slide
so the bore though the boring bar holder is concentric with the spindle,
and use that to hold the various turret tooling. And if they are truly
the same distance from dovetail to the center of the bore, you could
have multiple tools set up and just change them -- at least until you
need to use the cross-feed to part of the workpiece, after which you
have to re-establish the centering again.
Note just above the 5C holder is the #35, which holds a drill
chuck, but in such a way as to have better clearance from the the end of
the workpiece in a short bed leg. (Yes, I am looking through the PDF
file of the catalog.)
I have a long enough bed that I can use a Albrech chuck with 0.5"
straight shank I already have with the #36 (5C collets) in place of the
#35.
Yours is probably longer than mine. Mine is 24" between
centers, and I suspect that yours is 36" between centers -- encoded in
the last two digits of the model number.
Note that the BXA-22 also uses negative rake inserts, so if you
get that, it would be worth while also having the 16N so you could share
a single stock of inserts between both holders.
The #23 looks interesting -- offering two different angles of
attack in a single holder.
Again, I'm wondering if the difference over #16 is sufficient to own
both.
Again -- only if you don't have two of the straight-ahead
insert holders. I've got them, so I don't need it.
Hmm ... the #15 looks as though it would hold the PCD
(PolyCrystaline Diamond) inserts which I have. Those are very nice for
non-ferrous workpieces, but not for ferrous.
That was my impression too.
So -- I have to get a holder so I can use my two. :-)
[ ... ]
The #7 cut-off tool holder is good with the right blades.
I have a #7. Which blades are right, are wrong?
The ones which I like are the 'T'-profile ones. And in
particular, the Cleveland Mo-Max ones, which seem to no longer be in the
MSC catalog -- but there are some import copies which *might* be good
enough.
[ ... ]
The latest observation is that if I pry the workpiece up wrt the
cross-slide, the workpiece moves far more than the 3-jaw chuck, so it
may be that the workpiece is too irregular for the 3-jaw to get a firm
grip on.
Hmm ... this sounds like bell-mouthed chuck jaws -- ones more
worn at the tailstock end than at the headstock end, so it can't keep
the workpiece from tilting a bit under load.
It's possible for sure, although the chuck didn't seem that much used.
But it's easy to check.
It's always possible that a chip got between spindle and chuck.
That can cause chatter -- but it also causes loosening of the
pull-in ring.
Does your three-jaw chuck have two-piece jaws? If so, the first
test is to install soft top jaws and bore them to a reasonable fit on
the workpiece before clamping the workpiece. If this makes a big
difference, it is time to get a new set of hardened top jaws for general
use, and use the soft jaws when it really matters.
The jaws of both 3-jaw and 4-jaw chucks are indeed two-piece. I have
not yet figured out which top jaws will fit, and there are many choices.
Pull off a jaw, and measure the dimensions of the interface.
There should be a central ridge to keep them on center, and a raised
projection in the middle of the length to set the radial position
correctly.
MSC has them in catalog pages. Or -- you could machine up your
own on the mill. :-) Some of these days, I'll set up to make a few sets
of aluminum ones for really soft jaw use. I have two sets of steel soft
jaws waiting for the next project which really calls for them. (And the
Taig 3-jaw chuck is two-piece jaws, but without the precision placing of
the jaws. Just before boring the soft jaws, stamp them wit numbers
matching the master jaws which you mount them on, so you can repeat
precisely if you don't need to re-bore for a different workpiece size.
This was discovered while I was trying to figure out why the
cutoff bar in the BXA-7 holder chattered so badly. This theory that
it's the workpiece will be tested. What will also be tested is cutoffs
using a collet chuck. I did tighten the various gibs a bit, to no avail.
Did you try something soft, like mild aluminum or better soft
copper between the jaws and the workpiece?
Not yet. I've been machining steel on the theory that it is the more
severe test, and thus is useful for diagnostics. I haven't tried the
copper sheet approach yet, though I did think of it. First, I want to
try a less irregular steel bar, probably by turning the rough and rusty
outer surface off, and then chucking the newly machined bar in the 3-jaw
chuck. This will tell me if it's the bar, or the chuck.
Agreed. Be sure to use a live center to stabilize the workpiece
while turning it before you turn it over to get the truly cylindrical
part into the chuck jaws. Oh yes -- also check with a micrometer to
make sure that you haven't produced a cone instead of a cylinder.
Enjoy,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. |
http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---