Date
1 - 13 of 13
Carbide - Surface Finish - 9A
|
Mike Poore
Thanks for everyone's input. I did some more turning last night. I
increased the rpm to around 900-1000. I didn't calculate sfpm, but
it was much faster than my previous tests. The finish was indeed
better and close to good. The finish still felt torn, but not as
rough. I feel good using the advice that I am headed in the right
direction.
toggle quoted message
Show quoted text
Thanks, Mike On 7/14/2022 4:57 PM,
joebob4570@... wrote:
Part of what makes carbide so useful, besides its hardness, is it's resistance to heat. The higher speed you can run it, the hotter it is at the cutting edge. The heat softens the chip being removed, thereby making it easier to remove. The speed and chip load leads to vibration which requires mass to dampen the vibration. To get decent to good finishes on a lightweight machine requires a sharper cutting edge and lower removal rates than are standard for most carbide inserts which are negative rake. The positive rake aluminum cutting inserts can give good finishes, depending on exact material, part size, etc.; but they are weaker than negative rake inserts so you may need to sneek up in cutting lods determined by depth of cut, feed rate, and speed. |
|
|
|
joebob4570@...
Part of what makes carbide so useful, besides its hardness, is it's resistance to heat. The higher speed you can run it, the hotter it is at the cutting edge. The heat softens the chip being removed, thereby making it easier to remove. The speed and chip load leads to vibration which requires mass to dampen the vibration. To get decent to good finishes on a lightweight machine requires a sharper cutting edge and lower removal rates than are standard for most carbide inserts which are negative rake. The positive rake aluminum cutting inserts can give good finishes, depending on exact material, part size, etc.; but they are weaker than negative rake inserts so you may need to sneek up in cutting lods determined by depth of cut, feed rate, and speed.
|
|
|
|
Pretty sure that was before I put this machine in service. Not a great deal of history on it. All I really remember is that he lucked into a largish bag of inserts, low-cost or free, and is using what he has even if it isn't the best thing for his purpose... May have been on the homemadetools.net site, and my profile history there only goes back to mid-June. If it's one of those, I don't recognize it. Bill in OKC William R. Meyers, MSgt, USAF(Ret.) Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement. SEMPER GUMBY! Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better
On Thursday, July 14, 2022 at 12:04:34 PM CDT, mike allen <animal@...> wrote:
Check your history ? animal On 7/14/2022 8:33 AM, Bill in OKC too
via groups.io wrote:
There is a grade of carbide
insert for aluminum, and if you use it on cast iron or tool
steel it might not work well, might chip badly, etc. One of
the guys I was watching on youtube recently had a bunch of
that stuff and was using it for everything he did, but he
had to play with feeds and speeds to get it to work on the
material he was using, which was mostly not aluminum. Wish I
could remember who it was... Finding it might help you out.
Best of luck to you, and hope this helps you.
Bill in OKC
William R. Meyers, MSgt, USAF(Ret.)
Aphorisms
to live by:
Good judgement comes from experience.
Experience comes from bad judgement.
SEMPER GUMBY!
Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better On Thursday, July 14, 2022 at 10:02:52 AM CDT, Mike
Poore <mpoore10@...> wrote:
Ideally, I'd like to be able to use one tool to take
a heavy cut followed by an acceptable finishing cut. Is
that possible with carbide on a 9A?
You and Ondrej recommend 400-600 sfpm with carbide. I take it carbide cuts better at a faster sfpm? Maybe I misunderstood carbide usage. I thought it was capable of faster cutting, but faster cutting was not essential for a good cut. I know the speed effects the chipbreaking, but I did not know slower cutting will actually make the finish worse. So will cutting at a lower sfpm lead to the tearing finish that I wrote about originally? I have about 100# of various carbide inserts, so I'd really like to find something I can use rather than buying something else. Mike On
7/14/2022 10:10 AM, Bill in OKC too via groups.io
wrote:
I'm afraid that you need a much sturdier/more
massive lathe than the lighter SB lathes. My
experience is with Clausing-Colchester 13 & 15
inch school lathes. The smaller 13" lathe weighs
about 2700 pounds, the 15" lathes about 3800lbs.
My Heavy 10L weighs just over a third of what the
smaller CC lathe weighed and about has to be a
great deal less stiff. Mild steel, in our class
was specified 90SFPM for HSS, and 400SFPM for
carbide tooling. I could get a mirror finish on
the 13" lathe. I've not gotten to use my SB yet,
just the Atlas. It's about a quarter the weight of
the SB. Pretty much spaghetti comparatively.
Unless your SB is one of the newer lathes and a
14" or larger you're going to need slower speeds
and feeds, and shallower cuts to make up for the
lesser stiffness.
You could use carbide for roughing cuts, and
HSS for finish cuts if you really need or want the
fine finish. You can diamond hone HSS &
carbide if you need it sharper, but that can mess
up your repeatability with indexable inserts.
Arwarnerco.com sells HSS indexable inserts
which the folks who use 7x mini-lathes a lot seem
to find very helpful. LittleMachineShop.com sells
the smaller sizes appropriate for the 7" and
similar machines, and in smaller quantities IIRC.
HTH!
Bill in OKC
William
R. Meyers, MSgt, USAF(Ret.)
Aphorisms to live by:
Good judgement comes from
experience. Experience comes from bad
judgement.
SEMPER GUMBY!
Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better On Wednesday, July 13, 2022 at 09:46:54 PM
CDT, Mike Poore <mpoore10@...>
wrote:
I
am sure this is not the first time for this
topic, but I'd like to know what setup, if
any, anyone has found that provides a good
surface finish using carbide on 1018?
I have acquired a lot of carbide inserts and holders along with my QCTP. I have negative rake and no rake holders. I have chipbreakers and flat carbide. I turned some aluminum after rebuilding the lathe and the surface finish was as good as one could expect so far as it was nearly a mirror finish using the slowest feed. Then I tried 1018 with the same tooling and ended up with a fairly rough finish. It looked and felt like the metal was tearing rather than cutting. I have tried other combos and nothing yet is satisfactory. I have a diamond disc sharpener, but I think the carbide is sharp enough to do better than it is. There is plenty of HSS laying around that could be used, but the idea of indexable carbide would be preferred if I can make it work. There is plenty of experimenting left to do. I was hoping someone could give me a starting point as far as insert shape, rake, speeds (I am guessing it might be a little different than what the book says for an old WWII cast iron bearing lathe.), and tool angle. Thanks for any help. |
|
|
|
mike allen
Check your history ? animal On 7/14/2022 8:33 AM, Bill in OKC too
via groups.io wrote:
|
|
|
|
mike allen
I have a set of eh AR Warner HSS insert tooling for my SB
9A & I think rather highly of them . Had them 6 or 7 years now
& still using the inserts that came with the kit . I still
haven't got the recipe down for turning CRS & HRS , but that's me not the inserts . animal On 7/14/2022 7:10 AM, Bill in OKC too
via groups.io wrote:
|
|
|
|
When I got my first lathe, an HF 7x10, all I could afford was the cheap brazed carbide they sold, and it was definitely crap. The chips of carbide were not ground at all, and the they were brazed on blanks that presented the bottom edge of the carbide chip out in front of the top (should be cutting) edge. Everyone said you needed silicon carbide (green) grinding wheels to reshape them to be usable, but I was able to do it on an alox (gray) wheel. Still not the greatest tooling, but better than when I bought them. However, my 7x10 was not sufficient machine to use them, and I wasn't sufficiently good at machining to get any usable work out of them. Something about not being able to measure accurately... ;) I still have them here somewhere, may try them on the Atlas if I can manage to finish setting up the shop. I had my 2nd cataract surgery Tuesday, can't lift more than 10lbs, not allowed to bend 90 degrees at the waist, and not supposed to do anything like normal activities for at least a week. Good news, though, is that I can see well enough to drive and read with my old glasses. I'll get a new prescription in about 2 weeks, but no shop time for the next week, so I don't really need the new glasses. And I can read micrometers and calipers just fine as is! Bill in OKC William R. Meyers, MSgt, USAF(Ret.) Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement. SEMPER GUMBY! Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better
On Thursday, July 14, 2022 at 10:34:23 AM CDT, m. allan noah <kitno455@...> wrote:
I've had better luck using sharp, positive rake inserts intended for aluminum, even on steel. I've not found the negative rake or brazed carbide to be useful on a light lathe. On Wed, Jul 13, 2022, 10:46 PM Mike Poore <mpoore10@...> wrote: I am sure this is not the first time for this topic, but I'd like to know what setup, if any, anyone has found that provides a good surface finish using carbide on 1018? |
|
|
|
Ondrej Krejci <okrejci@...>
Greetings, And so, higher speeds lead to lower tool tip pressures and better finishes; hence, finishers have small nose radii. You may want to check the grades of carbide you are using if possible. There are various charts on the web.
|
|
|
|
m. allan noah
I've had better luck using sharp, positive rake inserts intended for aluminum, even on steel. I've not found the negative rake or brazed carbide to be useful on a light lathe. On Wed, Jul 13, 2022, 10:46 PM Mike Poore <mpoore10@...> wrote: I am sure this is not the first time for this topic, but I'd like to know what setup, if any, anyone has found that provides a good surface finish using carbide on 1018? |
|
|
|
I understand your concern! It depends on what you have. Some carbide is made a bit sharper than other carbide, but carbide is granules of very high-carbon material in a softer metal binder. The granules are usually some sort of crystal, so they may have sharp edges, but those don't necessarily present at the cutting edge of the tool. Grinders that are made for sharpening carbide tooling usually have diamond grinding wheels, but they may not be the finest grain. Personally, I use an Eze-Lap Super fine diamond hone on my HSS cutters, and cheap chinese import carbide inserts in cheap insert holders, so haven't worried about honing them. My home machines aren't large or heavy enough to take best advantage of carbide tooling. Your 9A is probably a better machine than my 10" TH42, but neither of them are super stiff. If you have a 10X loupe or magnifier, you can look at the edges and select inserts that seem to be sharper for your finish work. Carbide is mostly used in production shops to get maximum productivity in minimum time on heavy machines. You won't be able to take full advantage of it on the lighter machines, but you can do good work within the limits of machine. There are different grades and materials used in the inserts that work better for certain materials, and if you can identify what you have you can take advantage of those differences, but if they they're unmarked you'll just have to guess, and hope it works out. Carbidedepot.com used to have some really good info on selecting carbide inserts, but their site doesn't seem to be working anymore in the Brave browser I'm using now. Comes up fine in MS Edge, so you might want to check it out. There is a grade of carbide insert for aluminum, and if you use it on cast iron or tool steel it might not work well, might chip badly, etc. One of the guys I was watching on youtube recently had a bunch of that stuff and was using it for everything he did, but he had to play with feeds and speeds to get it to work on the material he was using, which was mostly not aluminum. Wish I could remember who it was... Finding it might help you out. Best of luck to you, and hope this helps you. Bill in OKC William R. Meyers, MSgt, USAF(Ret.) Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement. SEMPER GUMBY! Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better
On Thursday, July 14, 2022 at 10:02:52 AM CDT, Mike Poore <mpoore10@...> wrote:
Ideally, I'd like to be able to use one tool to take a heavy cut
followed by an acceptable finishing cut. Is that possible with
carbide on a 9A? You and Ondrej recommend 400-600 sfpm with carbide. I take it carbide cuts better at a faster sfpm? Maybe I misunderstood carbide usage. I thought it was capable of faster cutting, but faster cutting was not essential for a good cut. I know the speed effects the chipbreaking, but I did not know slower cutting will actually make the finish worse. So will cutting at a lower sfpm lead to the tearing finish that I wrote about originally? I have about 100# of various carbide inserts, so I'd really like to find something I can use rather than buying something else. Mike On 7/14/2022 10:10 AM, Bill in OKC too
via groups.io wrote:
I'm afraid that you need a much sturdier/more massive
lathe than the lighter SB lathes. My experience is with
Clausing-Colchester 13 & 15 inch school lathes. The
smaller 13" lathe weighs about 2700 pounds, the 15" lathes
about 3800lbs. My Heavy 10L weighs just over a third of what
the smaller CC lathe weighed and about has to be a great
deal less stiff. Mild steel, in our class was specified
90SFPM for HSS, and 400SFPM for carbide tooling. I could get
a mirror finish on the 13" lathe. I've not gotten to use my
SB yet, just the Atlas. It's about a quarter the weight of
the SB. Pretty much spaghetti comparatively. Unless your SB
is one of the newer lathes and a 14" or larger you're going
to need slower speeds and feeds, and shallower cuts to make
up for the lesser stiffness.
You could use carbide for roughing cuts, and HSS for
finish cuts if you really need or want the fine finish. You
can diamond hone HSS & carbide if you need it sharper,
but that can mess up your repeatability with indexable
inserts.
Arwarnerco.com sells HSS indexable inserts which the
folks who use 7x mini-lathes a lot seem to find very
helpful. LittleMachineShop.com sells the smaller sizes
appropriate for the 7" and similar machines, and in smaller
quantities IIRC.
HTH!
Bill in OKC
William R. Meyers, MSgt, USAF(Ret.)
Aphorisms
to live by:
Good judgement comes from experience.
Experience comes from bad judgement.
SEMPER GUMBY!
Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better On Wednesday, July 13, 2022 at 09:46:54 PM CDT, Mike
Poore <mpoore10@...> wrote:
I am sure this is not
the first time for this topic, but I'd like to know what
setup, if any, anyone has found that provides a good
surface finish using carbide on 1018?
I have acquired a lot of carbide inserts and holders along with my QCTP. I have negative rake and no rake holders. I have chipbreakers and flat carbide. I turned some aluminum after rebuilding the lathe and the surface finish was as good as one could expect so far as it was nearly a mirror finish using the slowest feed. Then I tried 1018 with the same tooling and ended up with a fairly rough finish. It looked and felt like the metal was tearing rather than cutting. I have tried other combos and nothing yet is satisfactory. I have a diamond disc sharpener, but I think the carbide is sharp enough to do better than it is. There is plenty of HSS laying around that could be used, but the idea of indexable carbide would be preferred if I can make it work. There is plenty of experimenting left to do. I was hoping someone could give me a starting point as far as insert shape, rake, speeds (I am guessing it might be a little different than what the book says for an old WWII cast iron bearing lathe.), and tool angle. Thanks for any help. |
|
|
|
Mike Poore
Ideally, I'd like to be able to use one tool to take a heavy cut
followed by an acceptable finishing cut. Is that possible with
carbide on a 9A?
toggle quoted message
Show quoted text
You and Ondrej recommend 400-600 sfpm with carbide. I take it carbide cuts better at a faster sfpm? Maybe I misunderstood carbide usage. I thought it was capable of faster cutting, but faster cutting was not essential for a good cut. I know the speed effects the chipbreaking, but I did not know slower cutting will actually make the finish worse. So will cutting at a lower sfpm lead to the tearing finish that I wrote about originally? I have about 100# of various carbide inserts, so I'd really like to find something I can use rather than buying something else. Mike On 7/14/2022 10:10 AM, Bill in OKC too
via groups.io wrote:
|
|
|
|
I'm afraid that you need a much sturdier/more massive lathe than the lighter SB lathes. My experience is with Clausing-Colchester 13 & 15 inch school lathes. The smaller 13" lathe weighs about 2700 pounds, the 15" lathes about 3800lbs. My Heavy 10L weighs just over a third of what the smaller CC lathe weighed and about has to be a great deal less stiff. Mild steel, in our class was specified 90SFPM for HSS, and 400SFPM for carbide tooling. I could get a mirror finish on the 13" lathe. I've not gotten to use my SB yet, just the Atlas. It's about a quarter the weight of the SB. Pretty much spaghetti comparatively. Unless your SB is one of the newer lathes and a 14" or larger you're going to need slower speeds and feeds, and shallower cuts to make up for the lesser stiffness. You could use carbide for roughing cuts, and HSS for finish cuts if you really need or want the fine finish. You can diamond hone HSS & carbide if you need it sharper, but that can mess up your repeatability with indexable inserts. Arwarnerco.com sells HSS indexable inserts which the folks who use 7x mini-lathes a lot seem to find very helpful. LittleMachineShop.com sells the smaller sizes appropriate for the 7" and similar machines, and in smaller quantities IIRC. HTH! Bill in OKC William R. Meyers, MSgt, USAF(Ret.) Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement. SEMPER GUMBY! Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better
On Wednesday, July 13, 2022 at 09:46:54 PM CDT, Mike Poore <mpoore10@...> wrote:
I am sure this is not the first time for this topic, but I'd like to know what setup, if any, anyone has found that provides a good surface finish using carbide on 1018? I have acquired a lot of carbide inserts and holders along with my QCTP. I have negative rake and no rake holders. I have chipbreakers and flat carbide. I turned some aluminum after rebuilding the lathe and the surface finish was as good as one could expect so far as it was nearly a mirror finish using the slowest feed. Then I tried 1018 with the same tooling and ended up with a fairly rough finish. It looked and felt like the metal was tearing rather than cutting. I have tried other combos and nothing yet is satisfactory. I have a diamond disc sharpener, but I think the carbide is sharp enough to do better than it is. There is plenty of HSS laying around that could be used, but the idea of indexable carbide would be preferred if I can make it work. There is plenty of experimenting left to do. I was hoping someone could give me a starting point as far as insert shape, rake, speeds (I am guessing it might be a little different than what the book says for an old WWII cast iron bearing lathe.), and tool angle. Thanks for any help. |
|
|
|
Ondrej Krejci <okrejci@...>
Hello, With finishing inserts, usually D or 55 degree tip, and 0.005" to 0.010" tool nose radius, about 600sfm and 0.004" to 0.008" feed/rev. work well on 10 series steels. OK
On Wednesday, July 13, 2022 at 10:46:53 PM EDT, Mike Poore <mpoore10@...> wrote:
I am sure this is not the first time for this topic, but I'd like to know what setup, if any, anyone has found that provides a good surface finish using carbide on 1018? I have acquired a lot of carbide inserts and holders along with my QCTP. I have negative rake and no rake holders. I have chipbreakers and flat carbide. I turned some aluminum after rebuilding the lathe and the surface finish was as good as one could expect so far as it was nearly a mirror finish using the slowest feed. Then I tried 1018 with the same tooling and ended up with a fairly rough finish. It looked and felt like the metal was tearing rather than cutting. I have tried other combos and nothing yet is satisfactory. I have a diamond disc sharpener, but I think the carbide is sharp enough to do better than it is. There is plenty of HSS laying around that could be used, but the idea of indexable carbide would be preferred if I can make it work. There is plenty of experimenting left to do. I was hoping someone could give me a starting point as far as insert shape, rake, speeds (I am guessing it might be a little different than what the book says for an old WWII cast iron bearing lathe.), and tool angle. Thanks for any help. |
|
|
|
Mike Poore
I am sure this is not the first time for this topic, but I'd like to know what setup, if any, anyone has found that provides a good surface finish using carbide on 1018?
I have acquired a lot of carbide inserts and holders along with my QCTP. I have negative rake and no rake holders. I have chipbreakers and flat carbide. I turned some aluminum after rebuilding the lathe and the surface finish was as good as one could expect so far as it was nearly a mirror finish using the slowest feed. Then I tried 1018 with the same tooling and ended up with a fairly rough finish. It looked and felt like the metal was tearing rather than cutting. I have tried other combos and nothing yet is satisfactory. I have a diamond disc sharpener, but I think the carbide is sharp enough to do better than it is. There is plenty of HSS laying around that could be used, but the idea of indexable carbide would be preferred if I can make it work. There is plenty of experimenting left to do. I was hoping someone could give me a starting point as far as insert shape, rake, speeds (I am guessing it might be a little different than what the book says for an old WWII cast iron bearing lathe.), and tool angle. Thanks for any help. |
|
|