Lathe not turning properly

[benjames]

I was turning my first piece of metal, trying to part a piece of the end of a long bar when the metal just stopped turning. I am thinking that maybe I advanced the tool too far and it jammed.

The motor was still heard to be running and now when I try and start the lathe it turns for a second or two and then stops and just makes a clicking noise.

Can someone shed some light on what has happened? I tried turning by hand to see if everything went back into place but it seems that I get one hard to turn revolution for every two or three easy to turn revolutions.

I have posted a short video of the problem on youtube:

http://www.youtube.com/watch?v=GvFT6tPMsNI&feature=youtu.be

Any ideas?

Ben.

 

[canadianhorsepower]

you could have broke a gear or
check your lever at the back if its fully engage
good luck

 

[Tin Falcon]

Wow:

First of all Never part between centers and never part with more than 2.5 times the diameter unsupported.
Looks like the parting tool is too low.

A bad setup likely broke the sacrificial gear.

download a copy of army TC 9-524 of some other basic machining manual. Read up on the basics ask questions .
And get a online or hard copy of the Machinery handbook.
If you have a setup you are not sure of take a pic and post it here . We can help.

Looks like you should have just used a saw.

Tin

 

[benjames]

OK guys thanks.

TIN:
Is this the book to which you refer?
http://www.amazon.co.uk/dp/0831128003/?tag=skimlinks_replacement-20

I have downloaded the army TC 9-524 and will give it a read.

Luckily for me Luc was right when he said about the lever at the back not being fully engaged. I thought it was going as far as I could push it when I moved it to LOW but when I applied some more force it budged over more and clicked into place. Now it spins fine every time. I was moving it towards low and stopping at the resistance I felt.

This episode has however been a wake up call for me to learn everything I can about each technique before I attempt it rather than learn all the mistakes myself.

Thanks for your help guys. I got lucky this time!

Ben

 

[MachineTom]

You need a real parting tool, what you are using there looks like a chinese E type tool, that is used to weigh down scrap buckets. If the steady rest were moved to with an inch or 2 of the cut, you had a correct parting tool, and did not use the center, and back gear was fully engaged, then you would have been successful.

Make Chips.

 

[benjames]

You need a real parting tool, what you are using there looks like a chinese E type tool, that is used to weigh down scrap buckets. If the steady rest were moved to with an inch or 2 of the cut, you had a correct parting tool, and did not use the center, and back gear was fully engaged, then you would have been successful.

Make Chips.

OK that's good to know, thanks Tom.

 

[canadianhorsepower]

you were lucky this time around
this hobby is fun but can be dangerous
the download that Tim sugested is more than what you need
after all their is 300 and some pages of information

enjoy

 

[Tin Falcon]

Well Ben IMHO no need to buy the latest edition.
There used to be copies of the older editions on line .
Just make sure you are buying the handbook not the companion guide unless you want both then buy both the guide is a textbook of exercises based on the reference book.
The machinery handbook is a reference not a how to. It will not tell you how to set up a part but is will give specs and tolerance for every thread known to man . And it will give lots of speed feed info for many y many metals.
It is not a sit down and read book but it has answers to lots of questions related to math engineering an machining.
Seems like you should be able to find an old copy for 10 pounds or so.

http://www.amazon.co.uk/gp/offer-listing/083112492X/ref=tmm_hrd_used_olp_0?ie=UTF8&condition=used
1914 edition
http://www.evenfallstudios.com/woodworks_library/machinery_handbook_for_machine_shop_and_drafting_room_1914.pdf
Tin

 

[bazmak]

Parting off is one of the more difficult operations.Avoid when you can.Make sure everything is to the book
if you have part/off or deep groove and take your time

 

[benjames]

TIN:
Thanks, I bought that one. That was really cheap! Thm:

BAZMAK:
I will be much more likely to use a saw next time and leave the parting off for when it is absolutely necessary!

Ben

 

[Wizard69]

Parting off is one of the more difficult operations.Avoid when you can.Make sure everything is to the book
if you have part/off or deep groove and take your time

I tend to agree with this perspective. However don't put those parting tools away, I often use a parting tool to cut a grove and then finish up with a hack saw or power saw. This works out well with larger diameters and and difficult metals like stainless. Of course
you need to clean up afterward by facing but usually you have to do that anyway.

Implemented properly, you can cut off smaller diameter stock no problem. You don't want to eliminate the technique just because of one bad experience. As others have mentioned feed rate and tool grind are very important. You need to remember you are generally taking a fairly wide cut with the parting tool. This means the chip load is significant. So when it comes time to buy blades consider the thinner offerings.

 

[benjames]

I tend to agree with this perspective. However don't put those parting tools away, I often use a parting tool to cut a grove and then finish up with a hack saw or power saw. QUOTE]

Would it be possible to make a sawing tool that you could put in the tool holder to save manual sawing?

Something like this:

If a small section of saw was soldered into a piece of metal would it work or is it a waste of time. I am thinking more of thicker pieces of metal.

Ben.

 

[Tin Falcon]

what you are proposing is not practical. You can if you desire make a parting tool from a hacksaw blade or utility kine blade.
Parting is al little funny . Not hard takes some practice. a thin blade is easier because less material is removed less work for the machine. But make it to thin the blade flexes an oscillates and then catches on the side and ugly things happen.
Like any other tool proper hight as stiff as practical and clearance everywhere but where the tool is cutting.
Tin

 

[benjames]

what you are proposing is not practical. You can if you desire make a parting tool from a hacksaw blade or utility kine blade.
Parting is al little funny . Not hard takes some practice. a thin blade is easier because less material is removed less work for the machine. But make it to thin the blade flexes an oscillates and then catches on the side and ugly things happen.
Like any other tool proper hight as stiff as practical and clearance everywhere but where the tool is cutting.
Tin

Thanks for the info Tin. So would the above work if it was a hacksaw blade?

Ben

 

[Swifty]

The trouble is Ben, that you would be only working mainly on 1 tooth, fine until that wears and then the trouble starts.

Paul.

 

[Wizard69]

It has already been mentioned but the problem here is that only one tooth will be cutting and that tooth will quickly clog with chips.

I tend to agree with this perspective. However don't put those parting tools away, I often use a parting tool to cut a grove and then finish up with a hack saw or power saw. QUOTE]

Would it be possible to make a sawing tool that you could put in the tool holder to save manual sawing?

Something like this:

Nope. I might have over stated my position above. I have no problem parting off small diameter stock where the stick out of the blade can be minimized. The problem comes with thicker stock that can not be easily cut all the way through nicely with a cutoff blade. In these cases I cut a groove, channel really and then finish the part off with a saw (bandsaw or hacksaw).

If a small section of saw was soldered into a piece of metal would it work or is it a waste of time. I am thinking more of thicker pieces of metal.

Ben.

In any event you really should look into some instruction on how to sharpen and set up a parting off blade. Once you get the hang of it it works good for small diameter stock. It is only with large stock that you need to find alternatives on these small lathes.
In general:
1. The blade stick out should be no more than required.
2. The actual cutting edge must be on center.
3. All required clearances need to be ground in. The blades seldom come from the factory ready to go. ALSO the cutting edge must be square to the blade body.
4. Don't even bother without lube if this is steel or aluminum.
5. Pay attention to feed rate.

Using a cutoff tool isn't impossible but you need to know the limits of the blade and the machine.

 

[benjames]

ok, thanks for your comments everyone. Very helpful. I think I will stick to a hacksaw and vice.

Ben. Thm:

 

[Philjoe5]

One point not mentioned is that when parting you are using a slow spindle speed (or should). Your feed rate needs to be slow enough so the blade doesn't climb up onto the work.

Watch the tool tip. You'll notice that the tool keeps removing material even when you've stopped advancing it. Don't feed faster than the cutting allows otherwise something will break.

Parting takes a little practice, then it's fairly easy.

Cheers,
Phil

 

[Philjoe5]

Ben,
Don't give up on parting. Although parting is not usually carried out with a center, there are times when you can use one.

Here I'm parting a water tank flange that's 0.157" thick. Without the bull nose center I was getting a lot of chatter. No surprise, there's a lot of work hanging out. So I basically cut most of a groove 0.4" deep, removed the bullnose, and cut the remaining 0.020" slowly until the ring dropped off



It would be tricky to make this part with a bandsaw.



Cheers,
Phil

 

[benjames]

Ben,
Don't give up on parting. Although parting is not usually carried out with a center, there are times when you can use one.

Here I'm parting a water tank flange that's 0.157" thick. Without the bull nose center I was getting a lot of chatter. No surprise, there's a lot of work hanging out. So I basically cut most of a groove 0.4" deep, removed the bullnose, and cut the remaining 0.020" slowly until the ring dropped off



It would be tricky to make this part with a bandsaw.



Cheers,
Phil

Cheers Phil. I guess being selective on when to use parting is the way I should go.

Ben Thm: