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How much lathe is too much lathe?

adamgoldberg

Iron
Registered Member
#1
If, for example, I needed to trim a AL 16od8id 8mm spacer down to 5mm ... would a full-size lathe be too big?



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12bolts

Global Moderator
Staff member
Active Member
#4
Are you considering getting a lathe? What do you consider as "full size"?
#1 What do you think, or know, you want it for?
#2 Have you got room for the intended lathe?
#3 How much are you prepared to spend?
#4 What sort of machining experience do you have?
You can do small work on a large machine but it sure can be tough to do large work on a small machine.
A big lathe can make some small jobs difficult. We are here to help you, but a bit more info would help us too

Cheers Phil
 

4gsr

Global Moderator
Staff member
H-M Supporter-Premium
#6
A 20" Lodge & Shipley lathe may be a bit too much to do something in the 5mm range. But to trim up a piece of material 12" diameter, it's was perfect!

My 9" South Bend lathe may be ideal for trimming something 5mm in size.
 

BGHansen

H-M Supporter - Premium Content
H-M Supporter-Premium
#7
If you are planning on turning small diameters (5 mm is fairly small) consider the max spindle speed of the lathe also. Tom's Techniques (great site, Tom Griffin is an excellent teacher) recommends spindle speeds of " 400 / work diameter " for plain carbon steel. Math works out to around 2000 RPM's for turning a 5 mm diameter. You'll be hard pressed to find a 20" lathe (for example) that spins up to that speed. In fact, a lot of 12" gear head lathes only go up to 1400 RPM's. You can do your work at a lower speed, but the surface feet per minute of material removal will not be optimal. We're pretty much all hobby machinist's here, not production shops, so optimal goes out the window and we work with what we have. The math on drilling an 1/8" hole in brass works out to around 8000 RPM's, my highest spindle speed lathe tops out at 2000 and that works fine.

Like mentioned above and on many other threads on this site, look for the largest lathe you can afford that fits in your shop. If you're buying used iron, if everything is working you'll be able to get your money out of the machine if you decide to upgrade down the road. An in great shape, well-tooled South Bend heavy 10" from 1954 has depreciated to it's bottom dollar so the only thing you're losing is the interest on your money if it had been setting in the bank. Of course you'd be missing out on all of the fun running the machine! Happy Hunting!

Bruce
 

tq60

Active Member
Active Member
#8
What is the "work envelope" of your planned work.

What is your shop space budget and what about your wallet?

We have had the disease for years and lost count at 8 lathes years ago.

We get what we can find and are always looking for the next one.

Had a few craftsman variants and the small hf one that we gave away as it needed work.

You constantly upgrade and collect tooling as you go.

They come with whatever and go with less...

Currently have 3, a Logan on a bench we cannot get to...A 14.5 SB that an antique dealer begged us to take for $250.00 and our 16 X 54 L&S.

for the small stuff and fast find we suggest the small hf 4 X 10 lathe as it has not changed in years and they maintain a parts supply.

Ours had broken back gear inside and bad belt.

Was making crankshafts by offsetting work so nasty interrupted cuts.

The friend was able to order parts and is using it.

The 3 jaw chuck on ours was very repeatable meaning you could remove the work and return it with little error.

Variable speed via a know we great.

They do go on sale and never show up on cl.

If you need larger work then get the small one for now and watch for the next one...

We were not looking for the SB but had to help out a friend and take it...


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British Steel

Active User
Active Member
#10
You7 can always adapt a small chuck to a big lathe but a big chuck will not fit a small lathe. don
There's also spindle collets for small work, my 13" Holbrook has through collets from 1/16 to 7/8", from there up it's chuck work and I have those from 4" up to 10"...

In a hurry I've gripped a small 3-jaw chuck in the 10" 4-jaw and used the 4-jaw to set eccentrics, 3-jaw to grip (repeat) parts.

Dave H. (the other one)
 

heli_av8tor

Iron
Registered Member
#11
I make small parts (diameters down to 0.050" sometimes less) for cameras and musical instruments on my Jet 1340. I made a collet body for WW collets that fits into the spindle taper. Maximum spindle speed is 3000 rpm. It would be nice if faster, but is adequate.
 

Desolus

H-M Supporter - Premium Content
H-M Supporter-Premium
#12
For me, it's more about the ability to hold work securely than the weight of the machine, look for a machine that has the ability to hold your work securely and rigidly and then consult your budget. If you can rigidly secure the work in the chuck, it can be turned.
 

grumpygator

Global Moderator
Staff member
Director
#16
I'll let ya know if I ever get there...My old Sydney can spin an honest 20" just under 5' long...Not very fast but I ain't in no hurry...Your only limitation is your mind...I've spent more time thinking about how to do a job then actually doing it...**G**
 

Desolus

H-M Supporter - Premium Content
H-M Supporter-Premium
#17
You and me both, I'll spend 1000 hours thinking about a 3 hour job...

Especially if that job entails some expensive material like stainless, or gold, or silver, or gem material...
 

wrmiller

Chief Tinkerer
H-M Supporter-Premium
#19
While this is true, it is lacking. I believe it should read, It's not the machine, it's the OPERATOR. I know many people that are not Machinists or Tool Makers that are very adept at operating a lathe. I also know a few that aren't.

"Billy G"
Bill's probably referring to folks like me... ;)
 

wrmiller

Chief Tinkerer
H-M Supporter-Premium
#20
I machine very small parts on a 20x80 gap bed at work all the time.
Define small please.

I had to make two grip screws and a firing pin for a old Colt M1900 a while back, and I sure as heck would not have wanted to even attempt that on your 20x80. I had a hard enough time on my 1340GT. I'm just glad I bought that little ER32 collet holder a while back.

I even had to mount my large lighted magnifier onto the lathe in order to properly see what I was doing. :)
 

Bob La Londe

Active Member
Active Member
#24
To much lathe is:
... more than you can beg borrow and steel. (Mis-pelling intentional)
... bigger than will fit in your shop.
... takes more electricity to power than you can provide.

Other than that, there aren't many qualifications for having to much lathe. I can slide 2" bar through the bore of my 14x40 or take out the gap bed and turn gigantic plates, but it also does a fantastic job on a 1/4" OD high pressure injector. My 7x10 will do a passable job on that 1/4" OD injector with some care, and won't do any of the rest of that stuff.
 

wrmiller

Chief Tinkerer
H-M Supporter-Premium
#26
After doing this stuff for a bit, I find myself thinking that big(er) lathes are best for big stuff, and small lathes are best for small stuff. My current machines are great for the larger stuff that I do, but I am seriously considering getting another Sherline or maybe a Taig lathe. Or possibly a Boley watchmakers lathe. Something a bit smaller where the machine/tooling doesn't get in my way when I'm trying to make small parts.

I don't seem to have the same issues when making really small stuff on my mill. :)
 

GoceKU

Active Member
Active Member
#29
My definition for a too big lathe is: if you need a crane to load it and unload the workpiece is too much lathe.
 

f350ca

Active User
Active Member
#30
My definition for a too big lathe is: if you need a crane to load it and unload the workpiece is too much lathe.
I have an overhead crane to change chucks and load shafts in this lathe. The 12inch 3 jaw weighs 90 pounds, the 16 inch 4 jaw 140 pounds. Had 300 pounds of 3 inch shaft in it the other day. But it will still do relatively small work.


Greg