Jim Timber
1/4 bubble off
My compound and CXA don't flex, but I always used the cross slide to move the tool except for threading.
What lathe?
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Lakeside53
Stihl Wrenching
HUH? Not useless but you have to be able to divide by 2 or other really complicated numbers, like 10:msp_ohmy:
If your compound is set to 30 degrees... Moving it one thou means it acually moves 0.5 thou to the work. Why, easy... sine (30) = 0.5
If your compound is graduated in thou, and you want it to read 10ths, that's dead easy. Set it to the 5.73917 degrees... Sine (5.73917) is 0.1
How do you set it to 5.7391 degrees? Use a sine bar, or a little trial and error and a micrometer. And of course, if you are shaving 10ths, forget carbide.
Personally, apart from threading (sometimes), for calibated (dial) tiny increments, for for profiling my compound is pretty much ignored.
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srcarr52
We can't stop here, this is bat country.
Brad, putting the tool at a more shallow angle will help your finish a lot but you can't expect a great finish on a cast piston using a small rake carbide. You'll need the hook of a CCGT insert or high speed steel with a large rake.
I too only use the compound for threading or to put a bevel on something. A dial indicator for the carriage makes life so much better but not as nice as a DRO would.
I too only use the compound for threading or to put a bevel on something. A dial indicator for the carriage makes life so much better but not as nice as a DRO would.
Lakeside53
Stihl Wrenching
I use CXA tooling on a very rigid lathe. Unless the material is difficult, thin section or other such issues, on greater than say 13tpi I just use the cross slide and plunge my threads.
On a light lathe, definitely use the compound with 29-29.5 setover for threading, and plunge only the last few thou for cleanup.
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Brad,
For aluminum kerosene, and mineral oil are good cutting lubes.
For aluminum kerosene, and mineral oil are good cutting lubes.
Only use carbide. Manual lathe. Have to split thousandths all the time in all materials.
6 TPI, no compound, no problems. ID and OD.
I don't understand the no carbine rule.
6 TPI, no compound, no problems. ID and OD.
I don't understand the no carbine rule.
parrisw
Tree Freak
LOL, I know there is a way with the math, but I wasn't going there. Who knows what his angle was??? I just saw him list he was taking a .005" cut and saw he was feeding the compound and thought, I bet its not a .005" cut.
Jim Timber
1/4 bubble off
Yeah, I forgot about cutting tapers without a taper attachment for the cross slide. I do that very infrequently with what I make. Dead center points and yes, an occasional bevel (I usually just use the edge of a tool for that) are good uses.
I learned threading @ 29.5 degrees, but there's no reason to use it if you don't have/want to. I do it because it's second nature and I get the results I want. CNC's go straight in, because you're right - they don't need to come in at an angle. The angle does help clear chips by only cutting on one side of the tool, and prevents galling/tears in softer metals.
I learned threading @ 29.5 degrees, but there's no reason to use it if you don't have/want to. I do it because it's second nature and I get the results I want. CNC's go straight in, because you're right - they don't need to come in at an angle. The angle does help clear chips by only cutting on one side of the tool, and prevents galling/tears in softer metals.
Tzed250
Addicted to ArboristSite
CNC turning centers only move straight in if they don't have advanced threading. An Okuma or other better machines thread by alternating cutting the front and backside of the lead. An excellent way to thread as both sides of the insert are used, but not at the same time. This leads to better accuracy and finishes.
Lakeside53
Stihl Wrenching
It's good to remember the 30 (or a little bit less if you do it that way) degree and 0.5 setup - that way you know how deep you are proceeding into a thread cut - just half of what you see on the dial, or just call the dial reading "diameter reduction" (but only at 30 degrees!). Very useful if you are using a thread mic.
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Lakeside53
Stihl Wrenching
Can
Not sure if you were refering to me, but I was"shaving 10ths", not splitting thou
Can you can shave a few 10ths in say 304 stainless with the type of carbide Brad has, or with most common inserts with min doc in excess of 3-4 thou? I can, but I prefer to cut it rather than rub it off. :msp_wink:I can cut all thread by just plunging, but my 16ER inserts would much rather run at speed, not at 28-180 rpm I typically thread at. The life is extended dramatically if I cut with the compound on larger threads. At the price I have to pay, I hate cruching the tips off.
Brad - to use your that carbide you should invest in a tool grinder (Baldor 500 or Chinese copy) and fit it with a diamond wheel (not CBN). I have a Baldor with a Diamond on one side, and CBN on the other (for HSS). Get a strong loupe to inspect the tips and edges. It's much harder to get a good edge on carbide (or at least, one that will last) than HSS.
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parrisw
Tree Freak
Yes. However I haven't tried threading much, only a couple times, with no success.
Not picking on anyone Lake;
I cut tenths too. Most all my work is .001 total tolerance. .002 when bigger. But when iris 9" long bore and the machine is 40 years old plus Monel or Hastalloy one tends to get intimate with types of inserts. LOL
Coatings is one thing that can caus chatter. Coated carbide has a radius on the edge. Carbide can be razor sharp. Diamonds too.
.0005 total tolerance on fits a foot apart with a TIR of .0005 and you use the the best cutter. Carbide is what is used. Diamonds when .000001 is needed.
I cut tenths too. Most all my work is .001 total tolerance. .002 when bigger. But when iris 9" long bore and the machine is 40 years old plus Monel or Hastalloy one tends to get intimate with types of inserts. LOL
Coatings is one thing that can caus chatter. Coated carbide has a radius on the edge. Carbide can be razor sharp. Diamonds too.
.0005 total tolerance on fits a foot apart with a TIR of .0005 and you use the the best cutter. Carbide is what is used. Diamonds when .000001 is needed.
confused
I am confused by the reference to the compound feed. The way I saw it, the cross feed was used, not the compound feed. The angle of the cutting tool may not be right, but it will move straight in. Correct me if I'm wrong.
I'm finding all this interesting as I have a mill and a lathe and am learning by doing. I have some photos to post on some machine work on a 272 cylinder that I did a little different where I cut the squish and base on the same setup. I just haven't had much time as I'm still trying to finish our house.
Larry
I am confused by the reference to the compound feed. The way I saw it, the cross feed was used, not the compound feed. The angle of the cutting tool may not be right, but it will move straight in. Correct me if I'm wrong.
I'm finding all this interesting as I have a mill and a lathe and am learning by doing. I have some photos to post on some machine work on a 272 cylinder that I did a little different where I cut the squish and base on the same setup. I just haven't had much time as I'm still trying to finish our house.
Larry
Jim Timber
1/4 bubble off
Carbide cutters are no different than saw chains in a lot of ways - you can have a razor sharp edge that cuts great for a short period but dulls quickly (chisel), or you can have a sort of duller tooth (semi chisel) that stays roughly the same forever.
If you want that razor edge, you aren't going to get it with the standard sintered carbide as it comes out of the molds (coating or not - they just aren't that kind of "sharp" as they're formed, it's simply a process issue with how they're made). You're going to need to lap it on a diamond wheel, or buy one that's been lapped from the get-go.
If you do end up doing a lot of manual threading, I highly recommend the aloris threading tool that uses a big chunk of HSS where you simply dress off the top edge to sharpen it (the cutter looks like an axe blade). I've had mine for several years and find it's awesome for both finish quality and longevity.
If you want that razor edge, you aren't going to get it with the standard sintered carbide as it comes out of the molds (coating or not - they just aren't that kind of "sharp" as they're formed, it's simply a process issue with how they're made). You're going to need to lap it on a diamond wheel, or buy one that's been lapped from the get-go.
If you do end up doing a lot of manual threading, I highly recommend the aloris threading tool that uses a big chunk of HSS where you simply dress off the top edge to sharpen it (the cutter looks like an axe blade). I've had mine for several years and find it's awesome for both finish quality and longevity.
Tzed250
Addicted to ArboristSite
Carbide inserts do not "cut" in way we are used to thinking about cutting. It is more a process of pushing the metal off of the part. The cutting action actually begins well above the edge, and the insert ends up using the metal to cut itself. This is one of many reasons why the inserts last so long and why they don't have to be "sharp" in the first place.
Any last minute suggestions before I buy this QCTP?
Tools4cheap LLC Online Machine Shop Tooling Store: Quick Change Tool Post Sets - Wedge Type,Quick Change Tool Posts and Holders
Tools4cheap LLC Online Machine Shop Tooling Store: Quick Change Tool Post Sets - Wedge Type,Quick Change Tool Posts and Holders
srcarr52
We can't stop here, this is bat country.
It depends on the type of insert. A CCGT 32.52 has a really sharp edge and can take a pretty small cut contrary to what has been said on this thread.
Here is one taking 0.001" cut. Sorry I had to stop the cut to take the picture for fear of crashing waiting for the iPhone to snap the picture. It was taking tiny curls off but they blow away as soon as they break off.
These inserts are supposed to be for aluminum and cast steel but I find they work well on finish cuts for most steel.
parrisw
Tree Freak
Nope go for it, just make sure you get the AXA size. They work well, you may want to order a few extra holders, I ended up picking up a few more off ebay.
Tzed250
Addicted to ArboristSite
The high positive rake inserts will take a very small DOC, but they are the exception rather than the rule in indexable carbide.
