finally got my lathe up and running need a little help with cutting techniques please
I finally got my lathe all set up working properly
I made a few little things on it just to play around with
I want to start making a few pieces for my old chopper project Im building
I need a little help as to what techniques and tooling that I should be using to
1. cut the end of a piece of tubing flush ( I think this is called facing ?)
2. drill an accurate hole in the center of a piece of solid round tubing (how do you stop the drill bit from shaking while its in the chuck of the tail stock ?)
3. simply turn down the outside diameter of a piece of round bar evenly ?
4. bore out the inside diameter of a piece of round tube ?
If anyone could post up pics of the right pieces of cutting bit that I should be using for each of these it would be greatly appreciated
also how the tool holder should be positioned to make these types of cuts
any help is greatly appreciated Ive never used a lathe before so sorry if this sounds like a stupid question
also this is a Logan 922 lathe and I have armstrong tool holders if that matters
I think you need to get a textbook of some sort. All of your questions are for very basic techniques.
One could recommend "Machine shop basics" by Carl Moltrecht as a starter.
I'd also include the "Machinist's Ready Reference". You probably won't use 99% of the info in it, but it will have everything you may need for calcs.
Cbell, Interesting post. I liked the part about the solid round tubing. I'll try to get you going. Think of the meatal as dirt and the cutter as a plow. The machine is ridgid enough to make the metal appear as soft plastic. You need to grind the cutter and set it into the tool holder in a way that allows to cutter to peel the metal away from the spinning stock. There are many books that describe how to grind the bit. If you have trouble finding a diagram, I'll post a snap shot of an image of a properly ground cutter with the various angles labeled. I'm talking about HSS bits, not carbide. If you're generally cutting soft steel, HHS bits are fine and are a lot easier to resharpen. You will need a good bench grinder with a fine grit wheel and a way to dress it to round. WWQ
1) Yes, that is facing.
2) The bit wobbles because it is off center. After facing it's often necessary to start your drill op with a center drill. These short and rigid little things really make a difference.
3) The evenness of your cut is provided by many things, primarily rigidity.
4) bore a hole with a boring bar.
Not to put a terd in the punchbowl ... But here is what i want to know...
I noticed over in the classified section there are rules against posting home or hobby type machines. After reading the rules I assumed this site was intended to be a place where professional machinist can assemble resources and experiences for the benefit of all machinist man kind.
With that said, It seams like there are a ton of people on here that are "home or hobby" machinists and have little or no experience at all. Not busting balls, but this guy knows absolutely nothing about the trade and would be "Almost a hobby machinist." I don't want to sound like a tool, but some of these "hobby" guys chime in when they really have no clue what they are talking about and its sometimes aggravating to weed through the clowns and get to the true practical machinists on this forum.
Its a great resource for people in the business to trade tips and experiences, but sometimes there are many posts that should not really be here. I don't mind helping people out, But I think that giving some people too much information is contributing to many small shops going out of business. I seen many people in different forums basicly teaching Chinese and India how to take more work away from us.
Thats my rant for the month!
I guess its time to find a new website if this is the general attitude on here by most members.
I am by trade a full time machinist and have been in the trade since I left high school alot of years back.
I have a full "hobby machine shop" that I make model engines and whatever I want or a friend needs.
Sometimes I even make a few spare dollars with the machines.
What brings me to this site is to talk with others interested in machining for whatever reason.
Than I read this and just say the hell with the site and Ill go somewhere else.
What pisses me off is I bet that if this "hobby machinist"
had a nice Blake coaxial indicator for sale for a very good price then I bet you would be willing to read his post.
I thought the name PRACTICAL MACHINIST was for everyone interested in practical machining.
My mistake,Ill find a new home
we all have to start somewhere,like myself,i have the need to learn.
if found inappropriate,the mod will soon take care of it.
not my place to make judgements here.
books and references are all readily available.
first and foremost,learn how to operate it safely,and develop good habits while operating your lathe.
As a home shop machinist that has come a long way, I'd like to suggest that there really should be a forum for Questions From Beginners. The pros can visit, or avoid, that forum as they desire.
I learned early on to respect the time and knowledge of experienced practical machinists by doing a lot of research online, reading books, etc. There really is no excuse for asking for basic advice when it's already online. if you can ask the question on PM, you can just as easily type it in Google Search.
If you can't find the answer, then come and ask here, imo.
Fact is that using PM's search engine can often get you the answer, without having to post any questions.
Go to a website " Lindsay Publications". This company reproduces books and magazines on many subjects including machining. You will see a paperback book from South Bend called "How to run a Lathe ,by South bend". This is a worthwhile $8.00 investment.It will answer the questions you posed here and more.
Start with this book, then practice with scrap.Even an old broom stick cut down to a reasonable length will teach you some things. I don't advocate using your lathe to turn wood, but just starting out like you I think it may help.You can turn between centers,then chuck your work and have some fun without breaking the bank.
There are many websites that show you how to grind your cutters correctly.Also there are many videos on the net showing you various techniques.
As far as I can tell 'tooling and/or technique' threads have never been locked.
Originally Posted by jamie76x
The metal doesn't change its properties based on weather its being machined in a home shop or a professional shop. It behaves the same weather it is on a $300 POS from Harbor Freight or if its on million dollar integrex. Manual or CNC, all the same basic principals apply.
We're all cutting metal. How to cut metal is very important to this message board.
I kind of enjoy the "basic" threads, brings a lot of it back to the front of my mind, I see how other people see things that I take for granted, I get to rethink the things I take for granted, and most of the time I learn something, since there are so many ways to do the same exact thing. Everybody has a *trick* for how to do something simple, I want to know all those tricks.
Badda Bing, Badda Boom!!
Originally Posted by jamie76x
So, if I take a .125 cut on a 2" diameter piece of steel on a Rong Fu lathe, it's going to cut the same as on a Monarch lathe?
Originally Posted by Bobw
Welcome to the internet. ALOT of good people and info. Gotta learn to seperate them from the keyboard commandos
Originally Posted by jamie76x
Let's look at it another way.
Being a newbie with a small, obsolete starter lathe does not equate with "hobbyist". For those of us without easy access to trade schools and apprenticeships, it's the only reasonable way to start learning.
Do you want to continue watching the term "Machinist" sink into the same category as "Buggy Whip Maker"? If so, continue berating the new kids for not knowing the Politically Correct terminology or how to work the lame search engine with the right buzzwords.
Otherwise, instead of bashing the newcomer for being uninformed, take it upon yourself to inform the poor clueless doofus. He probably looks a lot like you did a few decades ago.
You learned something from somebody. Don't let the knowledge die. Pass it on while you can. The earthworms won't be interested.
You can be the kindly old sage dispensing wisdom, or you can be the cranky old curmudgeon giving headsmacks to correct stupidity. Just don't be the bitter old asshole who takes his trade secrets forever to the grave.
Yep, it just might not be the workpiece that gets cut...
Originally Posted by 67Cuda
Once upon a time, in a far away place, a green young man went to work in a machine shop that supported operations and production in a large consumer products company. He was not really looking to work in a machine shop, he just needed a job. He was silent unless spoken to, willing to get dirty every day, and he paid attention to what happened in the shop. The "old guys", slowly became friendly, and the young man learned the basics of most of the old-time manual machines from their owners (old guys). Only one lathe man refused to share his knowledge with the young man. He said that he had to learn the hard way, the young man could learn that way too. When the chance came to do some small operation on a lathe, the young man had to seek out another lathe man, or go to the toolroom to beg pieces and knowledge. The old lathe guy always demanded that he help him clean his machine, but he always refused any semblance of teaching or even help for the young man, and don't even look at "his" lathe. Time went by, and the young mechanic was able to go to school and learn things for himself. He became a competent, even respected machinist. Over the years, he became foreman of a shop, then manager, then division manager with a large machinery manufacturer. As he got older, the business left him behind when it turned to CNC, computer design, and lean manufacturing. He stayed in touch with the friends he had made in that first machine shop, but they too had been left behind by technology and the passage of years. The former young man became the youngest guy at the funerals of those old guys. One day, he learned of the passing of the old lathe guy that refused to help him long ago. When he arrived for the graveside funeral, the funeral director anxiously asked him if he would help carry the casket, as there were not enough attendees to do it. As the former young man, now just a hobby machinist, carried the body of his would-be mentor to his final resting place, he wondered: "I guess he never taught anybody how to run a lathe." What a waste of a life, what a bitter way to pass the years, sitting on a pile of knowledge, refusing to pass it on to the next wave of machinists. What a come down, to be carried to one's grave by people who you rebuffed at every turn when you could have been their mentor. Every member of this forum swept the floor, ground the rough castings, installed the bearings in impossible, hot places, even broke the favorite tap of their mentor. It would be a shame if we ever got so constipated and self-important that we could not stand the sight of a beginner's honest question. Stupidity and ignorance hang well, if not comfortably, on a rookie, but it is an embarrassment to see them being dragged around by an "old guy. Regards, Clark
I am with TPMX on this. I am a retired machinist, also have a complete home shop, and make a few bucks once in a while. We all had to learn this trade, and not one of you was born knowing one single fact about machining. And yes, if I make a cut with my South Bend it is the same process and same result as doing it on the 25"X34" gap bed lathe I ran for a living. I don't have any use for anyone who thinks they are too special to give advice to a beginner. BYE.
Most likely not, but the material is going to behave the same, Surface speeds, depths of cut, feed, they apply equally to both machines. Horsepower and rigidity and tooling geometry are just a few more things to deal with.
Originally Posted by 67Cuda
You can learn things on a 100horse million dollar machine and transfer them to a POS chinese lathe that will fit in your glove box. and you can learn stuff on a cheap ass piece of crap and transfer that knowledge to the most expensive rigid machines. Manual or CNC, doesn't matter, the material doesn't know where it is, it doesn't know how big it is, it doesn't know if there is going to be a profit made on it or not.
Its metal, a certain metal in a certain condition, pretty much has the same properties as the next piece. Doesn't matter if its in my back shed or in a nuclear power plant.
I take surface speed into consideration when deburring with a hand drill.... so it applies there too.
Quoted for the ages.
Originally Posted by sealark37