Lathe chatter

[TraditionalToolworks]

Willie,

This sounds XLNT! I hope some of my dribble was able to either inspire you or help in some way.

That threading tool is still up for grabs if you want it, check your lantern post and see if it will work. You would need to use it in there most likely as it's pretty big, like 1-1/8" tall which would require a really large quick change holder. Measure the slot on your quick change as well as the size on your lantern square hole.

This shank on the Williams threading tool is: 1-1/8" Height x 1/2" Thick

Not useful for turning, only for cutting external threads. Would be a good match for your machine though.

[Willie B]

Willie,

This sounds XLNT! I hope some of my dribble was able to either inspire you or help in some way.

That threading tool is still up for grabs if you want it, check your lantern post and see if it will work. You would need to use it in there most likely as it's pretty big, like 1-1/8" tall which would require a really large quick change holder. Measure the slot on your quick change as well as the size on your lantern square hole.

This shank on the Williams threading tool is: 1-1/8" Height x 1/2" Thick

Not useful for turning, only for cutting external threads. Would be a good match for your machine though.

I'll make it work! The lantern is probably 2.5" tall, but has a curved shim to fill a gap.

I've got quite a pile of not for my machine tooling. If I knew what fits, the rest is up for grabs.

Dad claimed his being an electrician was punishment. He worked for Mac Molding 1953 to 1963. He moved around a bit in the plant, but refused to join the union when the Mafia moved in. The old electrician was said to be impossible. Difficult people were my father's greatest expertice. (He stayed married to my mother, I'd have shot her!) His WWII & Korean conflict aircraft mechanic background, he had some tooling. His brother went to CT before WWII, enlisted, but spent his working years as a hired gun millwright in hundreds of factories. He set up machines, and repaired them later. A close friend bought a defunct ice cream plant, and set up a machine shop. He was getting very old by the time I was involved in his struggles with the State electrical inspector, then town Zoning officials. The machine shop was mostly building cotton candy machines, refurbishing carnival snack wagons, calliopes, organs, steam engines, etc. by the time I was involved. I ended up with a few buckets of stuff that cost a fortune but wasn't very valuable.

I befriended an 80 year old bus driver when I was in high school. I had passing acquaintance with his machinist son. He was never a machine shop to pester with one of a kind projects, he built snow guns production, couldn't keep up with orders. At 75, he decided to move to Utah where all the other Mormons go. I acquired a couple buckets of tooling then.

The lathe was a matter of not being quick enough to say no. An electrician friend was selling a building. It had to be empty.

Most of what I've bought in tooling was unusable on my slow lathe.

Yes! You & a few others have been invaluable in my stumbling education as a turner.

Thank you, and thank you to all the others who have provided some insight. Don't imagine your work is through.

Willie

[TraditionalToolworks]

I'll make it work! The lantern is probably 2.5" tall, but has a curved shim to fill a gap.

It's yours. Send you a PM with your addy, I'll even pay the shipping, no worries.

[Willie B]

Today didn't go so well.
I began cutting a 1-3/4" hole with a hole saw through a piece of hot rolled mild steel. That went fine. After passing through 1" steel, only a few hole saw teeth lost their paint, and still feel sharp. Truing it to 1.972 went very well.

I then wanted to make a facing cut on the plate to create a surface perpendicular to the bore. The plate is vaguely shaped like a capital R. Doing a facing cut was impossible. I eventually figured out my 300 LB carriage was walking away. After resolving the problem, the tool kept sticking, locking the whole lathe up, and slipping the belts. It took hours. I tried numerous grind shapes, & honed the tool several times. Ultimately, I cut .080" off the legs of the R, before I got .002" from the center of the faceplate.

I mounted the odd shaped piece on the 18" faceplate by bolting four 1/2 X 2 X 4.5" pieces with $9.00 each bolts for the purpose from Mc Master Carr. Holding eack piece of 1" stock in place with the tailstock, I MIG welded heavy tacks to the bolted tabs. Not yet sure what went wrong.

[TraditionalToolworks]

I then wanted to make a facing cut on the plate to create a surface perpendicular to the bore. The plate is vaguely shaped like a capital R.

This is a very difficult cut as it's interrupted, if I understand you correctly. You will only be able to get a very small cut with such large interruption. This might have been better suited for a surface grinder if you could get it mounted completely vertical.

I wouldn't think you could get more than .002"-.003" without causing real issues. Some tools are not very well suited for interrupted cuts also.

Not yet sure what went wrong.

The lathe was the right tool for the bore, but not sure it was the right tool for this job given the shape. Probably should have been taking .001"-.002" on each pass. Once you cut past the interruption, it should turn cleanly into the center. I may be envisioning this incorrectly, that happens on the Internet.

[Willie B]

This is a very difficult cut as it's interrupted, if I understand you correctly. You will only be able to get a very small cut with such large interruption. This might have been better suited for a surface grinder if you could get it mounted completely vertical.

I wouldn't think you could get more than .002"-.003" without causing real issues. Some tools are not very well suited for interrupted cuts also.



The lathe was the right tool for the bore, but not sure it was the right tool for this job given the shape. Probably should have been taking .001"-.002" on each pass. Once you cut past the interruption, it should turn cleanly into the center. I may be envisioning this incorrectly, that happens on the Internet.

I believe you've got it, a big 1" thick irregular shaped piece of plate bolted with 1/2" tabs welded on to a faceplate. I've done two now, the first I used a carbide triangle cutter. It left thousands of strings of steel sticking off the surface, I had to clean up with a flap disk on a angle grinder.

This one I used a cobalt cutter in the lantern holder. I think I started wrong on cutter height as the lantern pretty much sets you at one height.

[TraditionalToolworks]

I've done two now, the first I used a carbide triangle cutter.

Honestly, this is probably one of the worst tools you could have picked. Carbide is actually not very good for interrupted cuts, and the reason is that it's very brittle. I'm surprised you didn't break the cutting edge off one or more of the corners. Carbide will often crunch the cutting edge if you run it into the work abruptly. Also, most triangular carbide tends to be negative rake, another attribute that is probably not good for your lathe. I don't know what you used those...I digress. Just because carbide is brittle it wouldn't be my choice on an interrupted cut.

This one I used a cobalt cutter in the lantern holder.

I'm not sure what type of cobalt cutter you used, I've seen some brazed on square shanks that could work, but wouldn't be my choice either.

For an interrupted cut, I would probably pick something like this HSS toolbit I'm showing here. Ignore the opposite end where you can see it, that was used as a small grooving tool, but notice how simple and rounded the cutting edge is? The top is dished out with a small dremel cutoff disk to add clearance behind the edge, and you can see clearance on the front and sides where the sides slope down and in. This is just a good all around toolbit which I would grab if I needed an interrupted cut. I would also slow down the speed as HSS can tolerate and likes slow speed, carbide likes higher speeds. This toolbit could use a touch up, I could have used it on an interrupted cut last. Toolbits don't need to be perfect, but HSS with a nice edge will act more as a sheer. This is a great geometry for all types of turning, facing, even the corner of a shoulder. Simple and strong.

[Willie B]

Just a random piece of square stock like the one in your post. I ground it more square than yours, yours is more a spoon. and the holder tilts it at 20 degrees so top angle not needed. Barely legible, it might be 50 years old I made out the word Cobalt.

I haven't yet grasped whether I want a tight radius point doing the cutting, or a rounded spoon. The old South Bend book shows cutting with the blunt side of a cutter. Others cut with the tight radius part of the cutter.

A wood lathe makes sense, rub the bevel, roll the shavings diagonally across the edge.

[TraditionalToolworks]

Just a random piece of square stock like the one in your post. I ground it more square than yours, yours is more a spoon. and the holder tilts it at 20 degrees so top angle not needed. Barely legible, it might be 50 years old I made out the word Cobalt.

Willie,

Yes, now that you state it that way, I have seen blanks that were Cobalt. For some reason I was thinking it was TiN coated like drill bits and end mills. That would work fine.

I haven't yet grasped whether I want a tight radius point doing the cutting, or a rounded spoon.

Ultimately the actual cutting is done by only the section of the edge that catches the work, but this blunter spoon shape is stronger and more tolerant to an interrupted cut than a sharp point, IMO. I don't have any scientific studies on it though, I just use what works for me. There are many geometries that will work for this. With an interrupted cut it's always better to use slower speeds as a precaution, and that's one reason carbide is not always the best choice. It can work though, depending on the job at hand. Think of your Cobalt blank being similar to an HSS blank, it will work better at slow speeds than a carbide insert, in most cases. Also you don't need to dish out to a spoon shape, you could leave the top flat and it will still work on this. Spooning out the top will weaken the cutting edge also, but it seems to act as a chip breaker from my view. I had another tool ground like this one. In fact, I once bought a toolbox from an old machinist and inside were a lot of very clever geometries he had ground with various type of chip breakers ground in them...it helped to study those designs, many I still use to this day. This spoon design is one I borrowed from those toolbits. I like it. I've used this for cutting stainless, or other harder materials to turn. Carbide is not always the best tool for the job, IMO. Others may feel different, and always best to listen to someone that does this day in, day out, which is not me.

[Willie B]

It is my intent to avoid interrupted flat surfaces in future.

Thank you for your package. I got it. It'll fit my holder fine. I've only made one foray into threading, a pin for an 8' sheet metal brake I bought from KD Welding.

[Willie B]

This lathe stuff is sure full of peril! Resizing my pin. From 2" 4140 to 1.973. I first went in with a 3/8 center bit almost to the shoulder, leaving a conical 60 Degree hole. I then drilled a grease galley 4.5" deep 3/13" Diameter. I'll drill for the grease fitting & tap later.

I brought the center into the hole being careful I thought to make it not too tight. Oiled it & kept it oiled. Something went wrong. I noticed a bit of smoke, shut down, it was tight. I re set it, a few times, but the damage was done. The point is now missing from the center, and the 3/16" hole is welded shut. I haven't yet tried to drill it out. Not sure what the center is made of. Looks like it has been shortened before, only half of the ____ CO is legible. Elsewhere, someone etched "tail".

I've ordered a ball bearing center, but while I wait I'd like to proceed. Can I grind a new point on this? What are the odds I'll be able to drill out the stuff in the end of my pin?

[Willie B]

Wow! my keyboard needs cleaning!

[TraditionalToolworks]

I've ordered a ball bearing center, but while I wait I'd like to proceed. Can I grind a new point on this? What are the odds I'll be able to drill out the stuff in the end of my pin?

You can, but you will need a toolpost grinder. Funny thing is I mentioned above in this thread I had a toolpost grinder I would sell for $400. A guy contacted me on this forum and asked for pics. I gave him all the info, but he was in LA or FL. I told him it would cost about $60-$70 for shipping. No response. I put the toolpost grinder on craigslist for $500 and sold it the next morning. The guy was tickled pink to have found it, they list for about $3500 and it and the entire assembly was literally new, but the spindle was bought on Ebay.

I took that money and bought myself a Primeweld 225.

Just deepen the center drill and/or drill some clearance with another bit for the point and use this as-is. As long as it supports the end you'll be fine. Or wait for the live center you ordered, either will work.

It is possible to cut a 60 degree using your compound, but other factors come into play and I think it best for you to use yours as-is or wait for the live center at this point.

A lathe is like any other tool, even welding. You need to keep learning one thing at a time until you get proficient.

[Willie B]

You can, but you will need a toolpost grinder. Funny thing is I mentioned above in this thread I had a toolpost grinder I would sell for $400. A guy contacted me on this forum and asked for pics. I gave him all the info, but he was in LA or FL. I told him it would cost about $60-$70 for shipping. No response. I put the toolpost grinder on craigslist for $500 and sold it the next morning. The guy was tickled pink to have found it, they list for about $3500 and it and the entire assembly was literally new, but the spindle was bought on Ebay.

I took that money and bought myself a Primeweld 225.

Just deepen the center drill and/or drill some clearance with another bit for the point and use this as-is. As long as it supports the end you'll be fine. Or wait for the live center you ordered, either will work.

It is possible to cut a 60 degree using your compound, but other factors come into play and I think it best for you to use yours as-is or wait for the live center at this point.

A lathe is like any other tool, even welding. You need to keep learning one thing at a time until you get proficient.

I'm in the autumn of my years. I may not live long enough to learn from my mistakes. Each new lesson feels good, those that don't end in failure are best.

I just now used the center rest to finish.

I switched ends to cut to length, drill grease galleys, groove for the retainers, counter bore to protect the grease fitting, bore & tap.

The cut off was frightening, and the HSS parting tool chatters something awful. Near final cut off, It broke in half, locked up. The lathe went into flat belt slip. I killed it, When I started it again run out was visible. I went through the process of centering all over again, and somehow it appears to be straight.

The pin is finished except drilling two radial holes to meet the longitudinal grease galleys. Don't want to do those until the hoe is dismantled & I can get accurate measurements where bearing centers are.

[TraditionalToolworks]

The cut off was frightening, and the HSS parting tool chatters something awful.

It's the tool height, you're not on center.

[Willie B]

I put a lot of effort into getting center. If I'm off it is by a few thousandths. I don't know the reason, but I don't believe center is it. I have two HSS cut off tools. One fits the aloris tool holder. The other fits the Lantern tool post. The height adjustment on the lantern is a cupped ring with a crescent shaped caul. moving the caul changes the height of the cutter.To my eye, I'm dead center of the center punch mark I spent considerable time getting right.

[M J D]

Your parting tool may not have been perfectly square. Parting can be tricky especially when you start getting deep in a cut. You also need to use LOTS of cutting oil.

[TraditionalToolworks]

Your parting tool may not have been perfectly square. Parting can be tricky especially when you start getting deep in a cut. You also need to use LOTS of cutting oil.

Yes, that would be another reason, I was figuring it was square, shouldn't figure that...

Good to square it up with the chuck face using a 1-2-3 block, then tighten up the tool post.

Use the Aloris for that if you can. Make sure the cut off tool is sharply ground also.

[leightrepairs]

Also need to have a very rigid set up, and the shortest stick out of the cutting tool.

[idacal]

I think you said earlier that you have a couple of thousand play in your head stock bearings that will make parting almost impossible like you experianced, lots of broken cutoff blades and pour the oil to it may get a2ay with it sometimes then for no reason that i could see it would jam up and snap. i have when running my first lathe was use a course hacksaw while spinning the chuck It at least cut straight that way if i didnt need a faced cut

[TraditionalToolworks]

I think you said earlier that you have a couple of thousand play in your head stock bearings that will make parting almost impossible like you experianced

I have to disagree, .002" runout isn't very bad at all, many lathes are worse than that. I could be wrong though, but I'd hate to think a lathe with .002" on the spindle would be almost impossible to use.

[Willie B]

I'm not sure whether the grind shape was a factor, It appeared to be square, but I don't have 123 blocks, & any square I own is too big to fit in the space. I squared it by eye. There is zero run out in the shaft turning by hand, but there is a little motion in it when I lift with a 2x4 pry. I'd say .002 loose.

[TraditionalToolworks]

I'm not sure whether the grind shape was a factor, It appeared to be square, but I don't have 123 blocks, & any square I own is too big to fit in the space. I squared it by eye

Winner winner chicken dinner! Award to MJD

Yeah, you need a better way to square it up, by eye only works in horseshoes, unless you continue to adjust it until it cuts correctly.

Another way is to square up the Aloris to the chuck face, if it will fit between the jaws. You need to make sure the toolholder is square to the work. If the cutoff tool is ground correctly and sharp it should peel off metal which will curl cleanly without chatter, even when fed by hand.

[Willie B]

Also need to have a very rigid set up, and the shortest stick out of the cutting tool.

The whole operation is heavy duty. Lathe is 3000 LBS. I set every cutter up to barely clear moving parts. No stick out beyond absolutely necessary. This is not a mini lathe.

Thinking about it, small shaft, at center, Do I need any relief below the cutting edge?

I can't change the angle of the cutter, might it help to grind a bit of angle into the top of the cutter?

[William McCormick]

My lathe is an antique. It's heavy, handles 20" diameter, by 52" between centers. Chatter is a problem. I believe bearings are Babbitt. Anything longer than a foot will chatter. Between centers is better, but not cured. Is there anything I can do to improve?

I need a longer pin for a backhoe thumb. 2" diax14" needs to be .010 smaller to fit the bushings. Carbide cutter was awful! HSS, cleaner, but almost like a thread cut in it. I think I've got to throw it away.

I have an old one too, I bought the best heavy synthetic gear oil made no more problems. Unless the lathe hits 40-degrees, then it is a bit slow starting.

Sincerely,

William McCormick