My new lathe stand

[chunkolini]

Awful.
Has to be confiscated immediately.
Green is soo yesterday, and chequer plate? so nineties.

I will happily rescue and look after this poor abused lathe.

Chunko'.

 

[GeorgiePorgie]

I was told you don't use a small lathe for parting off, you saw them oversize and use the lathe to true the ends up.. This is from a friend who has a small lathe but used to use large ones.

Tell your friend to do a headstock mod ie change the headstock bearings to needle roller cage bearings,the standard bearings that come with the small hobby lathes are naff,also a carriage locking mechanism mod has to be done also if parting off is poor on the bog standard lathe.

Sorry forgot to add the the standard spindle and chuck has to be changed as well.

 

[GeorgiePorgie]

The Super C3 Mini Lathe is fitted with Ball Races as standard. Taper roller bearings improve the machine by running more accurately and producing less vibration - especially important when parting-off.

This applies to most machines.

http://www.arceurotrade.co.uk/Catal...Model-C3-Mini-Lathe/Model-Super-C3-Mini-Lathe

http://www.arceurotrade.co.uk/projects/C3_BC/pages/index.html

 

[GeorgiePorgie]

Here's what Myford have to say about their machines and parting off....
http://www.myford.com/meu/Tools/article_01-0014T.html

Bit of a mystery about their machines in respect to parting off as they're well built and rigid and its a bit odd the parting off at the front is the same difficulty as the clones of these hobby lathes.

 

[jugs]

Here's what Myford have to say about their machines and parting off....
http://www.myford.com/meu/Tools/article_01-0014T.html

Bit of a mystery about their machines in respect to parting off as they're well built and rigid and its a bit odd the parting off at the front is the same difficulty as the clones of these hobby lathes.

they're well built and rigid
Mmmm ! thast's a matter of opinion - narrow bed, flat ways, that gap a small spindel ..... rigid IS NOT the word that comes to mind for myford.
Dont want to start a flame war ...but
I have a smart & brown, (same work envelope as my new Myford ) 10" wide vee bed no gap, 4" head bearings, & 5 times the weight. I can take 0.120" cuts (myford= 0.015") & have parted 5" dia with no probs on it - THAT'S rigid .



The forces shown, [fig 9 on that link] say it all.

With parting, the main problems are

1 - chip evacuation. - so grind a shallow chipbreaker vee on top of tool.

2 - intermitant feed, overloading tool - dont do by hand, use power feed.

3 - lack of lubricant. dont spray or squirt - flood.

 

[GeorgiePorgie]

narrow bed, flat ways, that gap a small spindel ..... rigid IS NOT the word that comes to mind for myford.
Dont want to start a flame war ...but

Apart from this how does the saddle,tool post,carriage measure up?

I'm going by one I used 3 years ago,maybe it was tuned by its previous owner? the lathe had no history so I don't know if it was in original state or as I said tuned.

I have learnt that the factory standard machines are poor and a bit of tuning and modding can make them sing, and as you pointed out "the spindle" its one of the reasons I changed my spindle over to accomodate a larger thickness of stock.

Most of the mods I have done are from this page....
http://www.toolsandmods.com/mini-lathe-mods.html

and it parts fine now with mild steel but I struggle with Stainless...thats one tough cookie to part.

 

[Shox Dr]

I find it easier in some cases to use the parting tool to place a grove into the material and then cut through the rest with either the bandsaw or leaving it in the chuck and use a hacksaw, then face the piece off. obviously this is only suitable when it's the bit in the chuck that you need. Or the offcut part is big enough it can be re-chucked to face that off

 

[GeorgiePorgie]

Yeah but its defeating the object of what the machine was made for.

I mean imagine having a car without the brakes working properly....what do ya do? hack a hole in the foot well and assist them better with your feet.

 

[Shox Dr]

Very true but if it gets the job done, and done faster without breaking stuff

 

[garethp]

Nice looking stand!



As for the parting off, I can do it fine on my Myford. The Myfords are a well made hobby machine that works straight of the box, I find a lot of the imported chinese stuff is poorly made / finished and needs tweaking to get it to do a really good job. Stuff like Smart & Brown is good quality industrial kit, the weight and massive construction says a lot

 

[brookie456]

they're well built and rigid
Mmmm ! thast's a matter of opinion - narrow bed, flat ways, that gap a small spindel ..... rigid IS NOT the word that comes to mind for myford.

Can't argue with that Jugs, one's a "hobby" lathe, the other isn't

 

[gordsgarage]

Whats the parting off like on it?

I am a self taught machinist and do not claim to always do things by the book. My experience with parting off is just that...my experience. I have very few issues parting off with the machine. I always run low SFM, make sure everything is locked down, use a sharp cutter, and a moderate amount of lube. After struggling the first few times and having the work piece ripped from the chuck I finally got a feel for it. I think the biggest key, for me, is the feedback I get and, with practice, I was able to figure out just how much pressure I can apply in order to get a good cut without doing damage. I have no complaints with the parting off capablties of the Craftex.

Gord

 

[Pete.]

I see no problem with having shelves of stuff behind the lathe - if you can't reach stuff safely turn it off, if you can't and you don't then you should keep away from all rotating machinery.

Parting is quite feasible with a small lathe too. I made a parting tool by slicing a piece out of a skil saw blade. My lathe's a bit bigger than yours but not a great deal.

Cuts aluminium at high revs and powered cross-feed:

http://peterrimmer.myby.co.uk/vids/parting.wmv

and steel too, at lower revs but still powered:

http://peterrimmer.myby.co.uk/vids/partingsteel.wmv

 

[gordsgarage]

Nice work Pete, the videos are great. Gets me thinking I may need to speed up my RPM a bit. Thanks for posting.

Gord

 

[Pete.]

Using a rear-mounted toolpost is even better. Instant chip clearance and none of the tendency to grab.

 

[gordsgarage]

Using a rear-mounted toolpost is even better. Instant chip clearance and none of the tendency to grab.

Can you explain what the difference is between using a rear mounted tool post as opposed to running a conventional set up with the lathe in reverse and the part off tool mounted upside down?

Gord

 

[Pete.]

When you use a rear mounted toolpost, with the parting tool upside-down, the chuck doesn't un-screw itself because you are turning the lathe the normal direction.

 

[gordsgarage]

Thanks Pete, that makes sense. In my case my chuck does not screw on therefore I may try the parting off technique with my lathe in reverse.

Gord

 

[jugs]

Thanks Pete, that makes sense. In my case my chuck does not screw on therefore I may try the parting off technique with my lathe in reverse.

Gord

You'll end up with the same problems ( but in reverse )


The forces shown, [fig 9 on the link below] say it all.

Here's what Myford have to say about their machines and parting off....

http://www.myford.com/meu/Tools/article_01-0014T.html

QUOTE]

 

[gordsgarage]

You'll end up with the same problems ( but in reverse )QUOTE]

Not sure I follow jugs, the forces will be exactly the same. With the lathe in reverse and the part off tool mounted upside down the tool will be forced to lift thereby relieving the strain just as it would using a rear toolpost and the lathe running in the conventional direction. Am I missing something here?

Gord