Sidney 16 or Does anyone use big lathes here?

[nsfr1206]

My neighbor has a 16x40 Sidney for sale. It has herringbone gears and is about 10 feet long. My question is will a lathe this large work ok for small steam and ic engines? It has a round a 14 inch 4 jaw chick on it. Another thing is it's top speed is 562 rpm. Is this too slow? I have posted this elsewhere and get both answers on it as far as speed.

 

[Stan]

If your model engine needs a 18" flywheel, it is not big enough.

 

[Brian Rupnow]

That size of machine is both too large and too slow for model work.

 

[Tin Falcon]

depends on what scale you want to do. also do you plan on taking your models to shows in the future. I hear the old guys complaining about hauling 80 and 100 lb models to show.
just keep in mind the laws of scaling. Take a model with a two ince fly wheel . Make it a 6 inch fly wheel say the original model wieged two pounds the scaled up version now weighs 54 lbs.
Hmm
Tin

 

[nsfr1206]

Not gonna build em that big! Can't I do precision work on one this big? I understand that the rpm is a little slow for carbide on a small item.

 

[ShedBoy]

I have a 9 x 36 I think (dam imperial) and it is border line too big for model work but I also do alot of jobbing work so need the room and weight. Big machines require bigger tooling which equates to bigger costs. As Brian said it is too big. I need a smaller machine with more speed to go with my current machine 1500rpm is not enough really small bits. If you can get it for a decent price sell it on and get a smaller machine with tooling.

Brock

 

[Brian Rupnow]

Would you use a 5 pound sledgehammer to drive a thumbtack, or perhaps a chainsaw to sharpen your pencil?

 

[steamer]

Well generally I agree it's too big....but mostly because it's so slow

My 12" Logan goes to 2000 which is plenty fast enough.....but the tooling can be expensive

I usually say go for the bigger lathe....but maybe not this big.

Dave

 

[Jeremy_BP]

My opinion is that you can do fine small work on a lathe of that size. The only issue is that top speed. You'll need to be faster.
I've made some of my smallest parts on a 24" cincinatti, but it went up to 2500rpm.

 

[nsfr1206]

Ok. I'll probably pass on it. So what is too big? The way I understand it the size isn't an issue just speed.

 

[steamer]

Yup the old adage is you can do small work on a big lathe , but not big work on a little lathe.


but 500 rpm........geez that's slow.

Dave

 

[steamer]

Ok. I'll probably pass on it. So what is too big? The way I understand it the size isn't an issue just speed.

Well 9" anyway, should be good but 1500 - 2000 rpm top speed ought to be the low end ....I think.

There are 12" lathes out there that will go that fast. You could do worse. 5C collets are cheap but the chucks get pricey at that size range though.

Even a SB 9 is a bit slow in that regard at 1500
What say the rest of you

Dave

 

[Sshire]

As a new, first time lathe owner I'm just beginning to get a sense of feeds and speeds. When is the 2000+ rpm used. Is it because of the small parts diameter?

 

[steamer]

As a new, first time lathe owner I'm just beginning to get a sense of feeds and speeds. When is the 2000+ rpm used. Is it because of the small parts diameter?

Yes.

 

[Brian Rupnow]

I'm going to jump in here and offer up my advise. This is not advice from a professional machinists perspective, but from someone who has been machining for about 4 years now. I have built 10 air/steam engines, two gasoline engines, and 4 novelty devices to power with my engines. 90% of the material I work with is less than 1/2" diameter, and 90% of it is either brass or aluminum, with the remaining 10% being cold rolled steel. My lathe is a 9" x 18 Craftex Chinese unit from Busybee tools in Canada. I very seldom use carbides, because of the inability to get good surface finishes. I do occasionally use them when turning steel, but never on brass or aluminum. I sharpen my own HSS lathe cutting tools from 3/8" square blanks. My machine has 6 speeds---115, 210, 350, 550, 970, and 1620. I only use the 115 speed for parting off with an HSS .094" wide parting off tool. I never use the 210, or 350 speeds. I use the 550 for turning heavy cuts on steel, and take my finish passes on steel at 970 RPM. On brass and aluminum I generally do most of my turning at 970 RPM and take a light finish cut at the 1620 RPM. For drilling with a tailstock mounted chuck I use either the 550 or 970 RPM settings depending on the diameter of the drill and the material being drilled. I have only done a very little single point threading, but found that the lowest speed of 115 RPM is still to fast for me to consistently engage the half nuts and prevent a double start thread. -----Brian

 

[steamer]

I think we agree Brian

25 - 2000 rpm or perhaps higher

Most small lathes really prefer HSS. They usually are not rigid enough for carbide.

Dave

 

[Tin Falcon]

well maybe I was taught to be a bit conservative. when I was in tech school we had to calculate speeds and feeds IIRC about 1000 rpm for aluminum 1 in diameter. but then we set the rpm to 5oo. i probably tend to run slow on my south bend lathe 9".
My 7 x10 has a speed range from 250 -2500
my little 5" bench lathe 250 - 4000
and the SB I am thinking 60 - 800 or so
You do have to be careful though large chucks have speed limits run them too fast and ugly things happen.
Tin

 

[lathe nut]

nsfr1206, if the price is right get it, you can make do, you can do little work on a big lathe but you cannot do big work on a little lathe, course don't take my advise, this is coming from Lathe Nut, I will buy ever lathe I find if the price is right and the wife is in the mood.

 

[shred]

Once you get above 12-14" swing (US measure), then the chucks and such start to require hoists and rigging equipment to change...

 

[nsfr1206]

Wow. Lots of great advice. And I appreciate every bit of it. :bow:

So if a lathe is hard to thread with at 115 rpm and certainly want one slower than that.