Good chart & info. Don't know about other moldmakers, but we were not
to concerneed with RMS. Its heat generated whilst grinding, directly
relating to flatness & size.
Yes its the dress, Alice.<g>
Don't use a "ball bearing" diamond, as many do. I like to finish
dress wheels above 100g with a sharp diamond. You can hear the
sound.... shooooooooo, & feel the grit hitting you in the face<g>
Simply put you are opening up the pores of the wheel instead of
pushing them over.
My fav all around wheel= Norton 46H/I - Hey Norton! ya Ralfy boy!
So that being said & done, WTF is the wheel to use on Titanium alloy?
mostly dry. We use the green silicone carbide 60g - soft wheel -
breaks down quick, but still gernerates heat like crazy! & loads, but
not as quick as Aluiminum oxide wheels. I've suggested, at least try a
"cold gun", they aint that expensive! Oh well...... the horses don't
want to drink. I've been looking to buy my own, damn local industrial
supply places aint open Sat. any more. The "rigged" air hose trick
helps in a pinch & also a mr. Misty or mrs. Misty, its personal
preference, mine is miss misty- cool,& always wet.<g>
Yeah, for truing the grinding chuck, I'd dress the wheel about as fast
an I could crank the handle, then come make a pass and move the table
over almost the full wheel width, make another pass, move out another
1/2" and continue. Very little heat and you'd end up with very flat
tables with a finish that had miniscule grooves in it that could trap
dust and grinding grits when "wringing" your part down on the table.
Temporarily drape a damp rag over the back parts "catcher" support,
then most of the grits hit the rag and fall straight down rather than
ricocheting all over the shop and under the grinder's ways. Don't
leave the rag there when you start grinding or you'll may set it on fire.
46H is sort of a universal wheel for Die Makers (which I was in a
former life). If you need sharp corners you'd go back in with a 100J
or if you REALLY needed a sharp corner a 120K wheel.
Did you try pushing some candle wax in the wheel and applying a light
brushing of oil on your part when grinding titanium? That I mentioned
about 3 months ago. It also works for aluminum grinding as well.
For corners I like an 80J with a negative 1-2 degrees on the face, so as you
dress the botton, the edge stays sharp.
I found the 100I get's me there. The wheel is a bit soft, but allows it to
But most of the time I use the 80J, and dress from the corner I want sharp
to the opposite corner. The diamond will lift the wheel, and as you come off
it, thats when it breaks the edge.
Lots of people say you can't get any sharper corner than the grit size, as
in you need a 120 to get a .0003 corner. Iv'e found that to not be true. I
can get down to a tenths corner with an 80. Maybe the grit is breaking and
creating sharp corners smaller than the grit size.
grinding titanium does require a cold gun, or coolent or something.
Oh well...... the horses don't
Yah but that stuff gets in your lungs. Maybe one of the newer models might
not do that. Maybe a micro drop.
I would try grinding with the face as opposed the bottom.
Try using something harder and finer, maybe an 80j. Dress the face smooth,
and the bottom dress a little rougher. As grinding, try to keep the spark on
the front tip of the wheel by feeding in as your traversing.
And use coolant or a cold gun.
If you have no coolant, get a cheap fish tank pump, and a bucket. Use rags
for the filter on top of the bucket.
I used to grind a lot of cpm10v, real nasty stuff, you couldnt side wheel
it whatsoever. But for flat grinding the above process would work great.
What you can do is set your diamond next to your part.
Dress your wheel.
Take a dust grind on your part, zero out your readouts or dial. Now go over
to your diamond using a stop and just touch it. record that number or put a
mark on the dial. (thats the relationship of the wheel to the part)
NOW...you can grind a pass, then go dress your wheel, when done dressing,
reset the dial or readout to the number you recorded or the mark you made.
You are exactly back where you were. Go grind another pass, dress, reset the
It's real fast... homegrown wheel comp.
Good stuff! Thx guys. Vinny your a manual CNC head.<g> I do the same
with the diamond setup outside my work travel, come over & feed into
it, longitudinal, continue dressing by down feeding, then back over to
your work,move light to left,looking down the work from the right, can
usually eyeball within a few tenths. Why do people put the light on
the right? Opitidressers are the ticket for form grinding, if you have
an xtra 10k?
I have tried oil & crisco on Ti like Al grinding. not much difference.
But.... the light show is fantastic! You'd swear it was the 4th of
july! The burning little sparks of oiley Ti actually make a snapping
I turned the light off & had fun.- od grinding on the AB/harig
spinner- The service tech guys were ready to call the fire dept<g>
Let me start off by saying that personal preferences can vary all over
the map, and still work for each person.
An old time rule of thumb is that you use hard wheels (J) to grind
soft material and soft wheels (H) to grind hard materials. In Die
making 90 percent of what you grid is hardened (RC 62-65) A2 & D2.
Are you primarily grinding graphite? The sharp edge you create would
tend to break down pretty fast in hardened materials, and you have to
constantly adjust your Y in feed.
I always liked to dress a small (.050-.1) lip on the back surface. It
will last for a number of dressings with adjusting the Y position.
Good point, you always want to START at the corner you'll be using.
Since the corner your diamond comes off the wheel on can tend to take
chunks of wheel with it due to pressure. Kind of like flaking flint by
pressure in making arrowheads. That parallels what you said, but from
Soft grinding wheels tend to wear down the grits until the point that
they are flung out of the wheel when enough pressure is exerted. I
would say you could easily get away with keeping your corners sharp
grinding graphite, where they would be much more likely to break down
when grinding hard materials. Hence my use of fine grit wheels on
Misters are pretty common in most of the shops I've been in that have
some surface grinders. The evaporation of the liquid from your parts
really helps to draw the heat away. But you're right, some people have
a hard time dealing with mist though. You can always use a vacuum
apparatus on the grinder, and/of use a breathing mask.
Full face side wheeling on hardened material is asking for trouble.
Burning the material can create heat-checks and weaken the material,
even if later light cuts remove the evidence of the earlier burn marks.
Wet rags and a pan of cold water can do for some materials in a pinch,
but SOME sort of cooling is important. And make sure before you do the
finish pass that the part is at ambient temperature, even if you have
to go away and do something else for awhile.
That's a good tip. You have to have a very stable diamond (that won't
move during dressing forces), and an accurate X stop.
I tended to just count the hand crank revolutions (up or down) to
reach the diamond. That would get me close and a little 1/2" wide
Magic Marker line would help me pick up where I left off. You don't
want to mark the whole length of your part (unless it's warped), since
you don't want to load your ultra-fine wheel with Marker ink.
I'm actually surprised! A relatively On-Topic thread lasting more
than two posts in here. LOL
Not really what I meant. When grinding I would use a wheel with a flat
dressed face, still grinding like normal, but while traversing, cross feed
in to the point the spark is on the face of the wheel.
Not sidewheeling, but technically it is.
Even if just taking a 1/2 a thousandth, keep the spark on the front of the
wheel. Cross feed too slow and it will wear the wheel.
Same concept as hard milling, keep the spark out front and the heat is
concentrated in front of the wheel, and that part grinds away.
AH side grinder head! joke when you see your co workers trying to push
back heels on inserts.
When alot of stock has to be taken off a face, I hand relieve the face
with carborandum or the diamond holder standing up on the magnet, till
just the corner of the face has a small flare, like making a cup wheel
out of it. It wears but can really remove stock without that burn/heat
checking. Feed right into the work-(side grinder head)<g> not down for
roughing. The finish will be an X pattern on your part if your square
to the spindle, not just a C pattern(one side of the X) is what you
get most of the time, spindles not quite sqr to the cross travel?
Thats ok for shoulders & heels that dont require an nice surface
finish. Ya kinda screw up the wheel & you cant dress too much off the
bottom before loosing the flare.
Oh well its a perishable cutting tool!
Same kinda thing when bottom grinding like HSS. - releive the bottom
so only a small area like 3/16-1/4 of a 1/2"wheel contacts
I just pushed a 40mm R back on hardened CPM10v last week 1/2'! I was
amazed. Ya it got hot, but a couple of norbide swipes, by hand to de
glaze the wheel & it was good to go! OD plunge grinding. It was not a
critical R. I found a 1" 46h wheel in the cabinet all dressed from my
predecessor(retired now, but was a moldmaker in previous life-go
Old moldmakers/diemakers don't go away they just .....???? <INSERT
Exactly, place the wheel close to the part & let it run. The wind from
the wheel helps cool it down a little faster. Now work on G job.<g>
Ok, sweep or clean something if the boss is around.
Also not much input from the usual crowd either? Hmmmmmmmmmm wonder
Their taking notes? Copy, Cut & pasting to other more popular most
read BLOG's? Ah FYI: guys thats cntl<c> cntl<x> cntl<v> on your
keyboard "PEBCAK" still ROFLMAO
Ya how come were talk'in manual stuff then?
because good manual machinists make great CNC machinists- end of story
.0003 with a 80 grit wheel? I think you had a zero too many, Vinny.
A 90 degree corner is one thing, but when it comes to grinding really
fine threads or detailed profiles, we use 150 or even 250 grit.
Iv'e gotten below .0005 with an 80j no problem.
2-3 tenths with a 100I.
Of course..(no pun intended).
The problem with a v type form or a thread shape is there's no bond to
support the corner, so it basically falls off on rougher wheels when
When it comes to stuff like that it's basically a comprimise between what
a wheel can support and it's ease of dress.
As far as 250 grit goes, ok for an orange wheel grinding round stuff, but
for flat I would never
go higher than 100.
But it's way more complex than that.
For regular flat stuff I'll use a 32 hardness bond, but for round stuff I
use a 38 bond hardness.
A good wheel for grinding threads on round parts is a 38A120L.
A good wheel for flat grinding and holding a dead sharp 90 degree corner is
If you have butloads of round parts on a centerless grinder where there's
tons of pressure I'd use a green wheel(silicon carbide).
Lots of variables, lots of wheels.
Last place I worked had a 400 grit wheel. I wonder what dumbass bought that
wheel. Looked like cloth.
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