Sidney 16 or Does anyone use big lathes here?

[Pappy Frank]

I have two lathes, one is a South Bend that was made in 1928 and originally was a 16 inch swing. Someone put 2 inch riser blocks on it and it now swings 20 inches. It runs on a flat belt and a cone type step pulley and I have rigged a motor on it with an intermediate shaft so I can get the RPM down to 40. Top speed for it is about 600. I use it a lot but hardly ever over 200 rpm. I wish it could go slower. When I get the back gear replaced, and put it on its slowest speed, I have never done the math, but it will be very very slow.

My second lathe is a 14 X 36 and it is a modern lathe and its slow speed is 70 and top speed is 1200. I use the 70 rpm a lot, and seldom go over 360 rpm. When I do, I have only once gone over 800 rpm in the 6 years I have had it. I wish it could go slower at times, but I have never had need for a faster speed. I could easily still use it if the top speed were in the range you are talking about.

One thing to consider is that large lathes usually mean larger diameters, and when you get larger diameters it means slower speeds. So sometimes the need for slow speeds is a good thing. You can turn a small diameter part at slow speeds, but you cannot turn a large diameter part at fast speeds.

If the price is good, I would encourage you to grab it up. If you do not like it, you can sell it later.

I had no real need for my large lathe when I got it, but about two weeks ago I needed to have my flywheel from my pickup reground, and I was able to set it up and do it myself, saving me a lot of money.

Pappy Frank

 

[sncf141r]

(Hey, I used to have an old pre-Sidney lathe (Sebastian Machine Tool Company), that, from what I read years ago, was at least 100 years old. I found this out from the Sidney archivist. I'll have to dig out old 35mm pics sometime... The name rings a bell, anyway)

Have two lathes - British made 11" did swing x 24", and an Austrian 8" swing x 18??".

Both have their uses. If I had to choose one, it would be a hard choice - depends on other circumstances, like *why* I'd have to choose one over the other. :-\

I've had lathes kicking around 40 odd years now; agree slightly bigger is better. While I'd agree that faster is better; rigidity over slop rules. 8)

Your Sidney with herringbone gears is going to be smooth, I'd expect. They were a respected maker. If the price is right, and you have the space and right electrical connections, it might be great.

JohnS.

 

[user 4756]

Hi Brian,

115 revs as the lowest speed, that is really fast!

I am surprised that you don't have a backgear; my old Drummond Ms run 12 speeds from 25 revs to 900 and the Myford S7 has 16 from 27 revs up to 2100 (though you should not run backgear on the two highest speeds).

You may get better finishes at that top speed but it frightens the hell out of me, everything hums like it is trying to take off! I rarely work above 600/700 but then I am chicken :big:

I can't imagine trying to thread at that speed, I would worry that the thread would run up the headstock! :big: :big: :big: :big:

Maybe it is time I got the girls wound up and see what I can do then!

Andy

 

[kvom]

Assuming it's got a 3PH motor that you'd control via a VFD, you could ramp up the speed by 50% or so without doing any harm, assuming the bearings are good. I'd also suggest looking for a small chuck when doing so.

I find turning at 500 rpm works for steel pretty well, although for smaller diameters or drilling that might take some care.

A VFD would also allow slowing down for threading.

If the lathe can hold tolerances pretty well, it could work for you, esp. if the price is right.

 

[nsfr1206]

I have an RPC. Slowest speed on the lathe is 14 rpm IIRC. Wouldn't need much slower than that. :big:

 

[bezalel2000]

Hi Brian

There is clearly a consensus here that a lathe for model work needs a wide speed range (slow for threading and fast for the little bits) but little in the way of explanation that would enable you to work out for your self what you might need.

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?

The slow speed for threading is almost obvious - you don't want to crash the tool into the headstock. it takes only 1/2 a second to cut 1 inch of 10 tpi thread at 1000rpm.

The fast speed, is based on best cutting result for the materiel being cut,
expressed in surface feet per minute (100 SFM for mild steel is the easy one to remember)

So if the main purpose of the lathe is turning 1/8 inch Mild Steel spindles then a high speed of 3000 rpm would be preferred.

calculated by
rpm=cutting speed in SFM/ circumference of the spindle in feet

circumference of 1/8" = 0.033 feet
MS cutting speed = 100 SFM
rpm = 100/0.033 = 3300 rpm

Material Average Tool Speed HSS (S.F.M)
Magnesium 300
Aluminum, 7075 300
Aluminum, 6061 280
Aluminum, 2024 200
Aluminum, Cast 134
Brass 400
Bronze 150
Copper 100
Cast Iron (soft) 80
Cast Iron (hard) 50
Mild Steel 100
Cast Steel 80
Alloy Steels (hard) 40
Stainless 60

Bez

 

[Maryak]

Hi Guys,

IMHO it is the low speeds which are far more important for hobby work and small machines. The cutting speeds and feeds listed in most publications are for production work with machines correctly mounted and possessing the necessary rigidity to achieve a good finish. 9 times out of 10 problems with surface finish chatter etc. are overcome by slowing down the speed/feed, (occasionally the reverse is true).

A larger amount of metal removal, (depth of cut), is better achieved by a slower speed and a higher rate of feed. Do the calc if you don't believe me. Again bearing in mind the size of the machine and how it is mounted.

For lathes so fitted it is amazing how much of a model is built using the backgear. With my current lathe I have not yet changed the belt to provide the upper six speeds of the twelve available in 4 years of operation.

Just my thoughts and probably worth what you paid for them.

Best Regards
Bob

 

[8ntsane]

Hello Guys

Seen this post on the Sidney lathe, and didnt think anyone on this board used such equipment. Now to start with, I will say that I dont build micro tiny parts, small engines like most on this site do.

I do how ever, own and Run a 41 Sidney Lathe. I started out with a 12x37 Busy-Bee lathe that topped out at 1200 rpm, that was yrs ago, back arourd 1984.

The OP, has asked about a 16X Sidney, and the top speed seems to be a issue. The Sidney,s of that size were available with a low & Hi range spindles. The one the OP mentions is the low speed set up.. The hi - speed runs up to roughly 1000 rpm.

Another thing that is noteable with a Sidney, is they were allso available with 1200, or 1800 rpm motors. I would think the lathe mentioned has the 1200 rpm motor. So, if he wanted a faster spindle speed, he has options. First, change out the motor sheeve, and get up to 1000 rpm. Not fast enough? Use a VFD to bring it up to a higher speed. Or, swap the motor out for a 1800 rpm model.

So this machine is a 16X , there is nothing stoppin him from installing a smaller chuck on that machine. I run 6 to 12 inch on my 14X30 Sidney. The machine can use what ever chuck he see,s fit really. Most likely has a L-1 spindle, so adapting up for any chuck is easy.

Tooling, I dont see any reason why he can use a elcheapo AXA tool post like most of you guys commonly use. I use a AXA with a spacer under it on my Sidney, and a CXA for bigger work. So I dont see why some are telling him the tooling will be expensive. He can use the same stuff you guys do, with a spacer under the tool post of coarse.

The Sidney you are referring to is the Herringbone geared head stock. These puppys are one of the smoothest gear head machines ever made. One word of caution be for yo buy it. Run the mache at all the speeds, and make sure its quiet and smooth. Pull the top cover, to check the gears for missing teeth, chips or any damage. If you get that far with out any issues your looking good.

The Herringbone Sidney is a machine that is built for heavy work, not like most are doing here. But make no mistake about it, That old Sidney will be around making chips long after a import machine that was built today craps out, and is remelted into something else.

If you are only building very small items, maybe the Sidney is too big for you. But in most cases, you can deal with it. The Bigger machine can get good surface finishes, just use HSS cutters in lew of carbide. I would get that machine to run atleast 1000 rpm though.

I have not had a lathe any smaller than a 12X37 @ 1200 rpm, But I will say this, The bigger stuff is more ridgid, and that old saying. You can machine small parts in a large machine, but you cant do large parts in a small .machine.

Making chips since 1984, and Id still perfer the big machines over the tiny not so ridgid machines.

 

[f350ca]

Hi,
Im not a full time model builder, some day hope to have the time, and I've never ran a micro lathe but I've built a few models and done lots of fine work on big machines. Yes the bigger machines are more cumbersome to work around (bending over the apron of my 18 x 80 to watch a 1/4 in boring bar or internal threading gets hard on the back) but you can't beat the rigidity of 7000 pounds of cast iron.
If you have the room go for it, you can always speed it up by changing pulleys if you need it. You should never have problems with chatter or parting with that machine.
If smaller is beter for modelling why do most want a Bridgeport mill but may not have the space.
Just my thoughts for what they're worth.

 

[nsfr1206]

Alright folks. I am very thankful for all the replies. I was just over there looking at it and the owner hooked it up to power for the first time in years. Ran it and checked it out and that big old thing is awesome. Power feed in forward and reverse, lots of thread choices, and power slide on the cross slide. The low speed of 14 is SLOOOOOOOWWWWWW. And top speed of 562 is not real fast. But it seems to run real smooth. For some reason the oiler made a big mess on the floor though. The owner bought it at an auction at Mississippi State college and had never hooked it up. Looks like it will take up residence in my shop!!! ;D

 

[nsfr1206]

BTW, what kinda spindle does this thing have? Its got 6 square head bolts going in toward spindle behind chuck. The bolts are like what the chuck takes to tighten. Can't think of proper term here.

 

[lathe nut]

What, no pictures, you cannot do that to us, come on where is the picture, give it up, hope you get it, I love lathes, Lathe Nut

 

[nsfr1206]

The man brought the lathe over today and put it in my shop. I hooked it up and ran it. It has a 4 jaw 12 inch chuck on it and it wobbles . Not sure why. He had a chain down between the ways and up behind the chuck. Is there any way he could have put enough side or end pressure on the chuck to bend it or worse, bend the spindle?

 

[Tin Falcon]

He had a chain down between the ways and up behind the chuck.

probably not the preferred way to move it.
how bad is the wobble is the chuck possibly a bit loos on the spindle nose
how is it attached?
Tin

 

[ShedBoy]

th_wwp there worth a thousand words. Remove the chuck and run it up see if the register wobbles.

Brock

 

[nsfr1206]

Think the chuck is a d-1 6 camlock. That make sense? It has 6 half inch square drives behind chuck. Haven't taken it off so don't know what that looks like. And I don't even own a dial indicator. Yet. And the lathe has no tool post. Need to buy a QCTP also.

 

[Tin Falcon]

with the d type they are not bolts but cams that lock on cutouts in pins. so loosen everything up remove the chuck check everything clean and remount.
the way I learned to mount and dis mount was similar to a car wheel
loosten the cam then return so it catches but not tight work your way around then loosten each one completely. the same with mounting tighten then back off a bit work all of them then tighten them all.
IIRC I worked with D1 4s
Tin

 

[nsfr1206]

Just went out to shop and looked at it. And realized this thing has a tailstock on it for a 14 inch lathe. How could I have missed that? Good thing the man is letting me try it before I buy. I have little hope of finding a 16 inch tailstock. Riser blocks anybody? Opinions????

 

[bezalel2000]

Just went out to shop and looked at it. And realized this thing has a tailstock on it for a 14 inch lathe. How could I have missed that? Good thing the man is letting me try it before I buy. I have little hope of finding a 16 inch tailstock. Riser blocks anybody? Opinions????

That ought to be fine - All you gotta do is design everything to have a taper :

oh and rig up your lead screw to drive the height adjust on the QCTP

The perfect project for the Christmas break - Just kidding :big:

Bez

 

[steamer]

Just went out to shop and looked at it. And realized this thing has a tailstock on it for a 14 inch lathe. How could I have missed that? Good thing the man is letting me try it before I buy. I have little hope of finding a 16 inch tailstock. Riser blocks anybody? Opinions????

Walk away from the lathe.....would be mine...it seems it's been hacked 12 ways to Sunday.....

Dave