How accurately can a steel ring be rolled?

[Agroshield]

If you are worried about HAZ and machining after welding, bung the whole thing on the BBQ until it is red and throw into a bucket of vermiculite for slow cooling.

If you want the spindle to go slowly, drive it via a cordless drill on the end of the leadscrew with the gearbox set for the coarsest thread the lathe will cut. That will get you a slow speed but you will not be able to power feed your MIG gun. You could put a threaded rod out the back of the spindle with a coupler nut on it to move the MIG gun (you might need M20 or bigger as that would give you 2.5mm per revolution feed).

 

[Dee J]

273 x 6. 3 is the nearest here

Steel Tube suppliers - CHS - Circular Hollow Section Mild Steel tube

steel tubes - CHS circular hollow section, cold and hot finish tubing supplied from stock. Mild steel tube (inc. S355) supplied supplied to the construction industry throughout the UK.

www.steelexpress.co.uk

 

[addjunkie]

Could you get them metal sprayed professionally, then reground or machined to the size you want. If pressing in machined tube and plug welding then machining back

 

[Gritineye]

If you are worried about HAZ and machining after welding, bung the whole thing on the BBQ until it is red and throw into a bucket of vermiculite for slow cooling.

If you want the spindle to go slowly, drive it via a cordless drill on the end of the leadscrew with the gearbox set for the coarsest thread the lathe will cut. That will get you a slow speed but you will not be able to power feed your MIG gun. You could put a threaded rod out the back of the spindle with a coupler nut on it to move the MIG gun (you might need M20 or bigger as that would give you 2.5mm per revolution feed).

You're right annealing it should work, I may be over thinking this.

Good theory with the drill but this light lathe just would't last very long driving it that way.
I dug out and fitted the back gear to the positioner just now, but of course it doesn't work being driven by the spindle However if I drive the back gear spindle with a couple of small steering UJs that would work, and leave the lead screw usable, so that's the next thing to try.

The head stock back gear ratio is 6 to 1, the slowest speed is 28 rpm, so if my maths is right a second back gear should give me 4.67 rpm.

An on line calculator comes up with this:

A disc of 11" ( 11" ) Diameter
spinning at 5 RPM
has a Surface Speed of:
13.4 feet / minute
0.2 feet / second
161.4 inches / minute
0.15 MPH
4.1 meters / minute.

How does that look chaps, still too fast I reckon?

 

[Gritineye]

Could you get them metal sprayed professionally, then reground or machined to the size you want. If pressing in machined tube and plug welding then machining back

I could, but past experience has led me to try every way to do things myself to avoid undue expense and disappointment..

 

[Agroshield]

Good theory with the drill but this light lathe just would't last very long driving it that way.

The stress on the machine will be less driving it that way than driving it the conventional way. There is exactly zero cutting force involved in what you are doing.

Just for the sake of discussion, assume that the leadscrew is 8tpi and you want to cut an 8tpi thread. The overall ratio would be 1:1 in either drive direction.

If the gearbox allows coarser than 8tpi (let us assume 4tpi), in the conventional drive direction, the spindle will drive the leadscrew at 2:1. Reverse the direction of drive and the leadscrew drives the spindle at 1:2, a reduction.

It is a proven technique. Look up the Quorn cutter grinder - it has a 1 tpi square thread on the column for raising the head. The instructions show how to cut this on a Myford by driving the spindle via the leadscrew.

On the speed issue, say you were MIG welding in a straight line. What would be your travel speed there? The brake drum will be the same, just wrapped around a circle.

If you want to feed the torch across as it is rotating, you will need a coarse 'thread'. What width is the weld bead? How much overlap does it need? Let us guess at 6mm wide and 1/3 overlap. That means you need to set the gearbox for 4mm pitch (let us say 6tpi). That is what will stress the machine.

 

[Gritineye]

The stress on the machine will be less driving it that way than driving it the conventional way. There is exactly zero cutting force involved in what you are doing.

Just for the sake of discussion, assume that the leadscrew is 8tpi and you want to cut an 8tpi thread. The overall ratio would be 1:1 in either drive direction.

If the gearbox allows coarser than 8tpi (let us assume 4tpi), in the conventional drive direction, the spindle will drive the leadscrew at 2:1. Reverse the direction of drive and the leadscrew drives the spindle at 1:2, a reduction.

It is a proven technique. Look up the Quorn cutter grinder - it has a 1 tpi square thread on the column for raising the head. The instructions show how to cut this on a Myford by driving the spindle via the leadscrew.

My lathe has die cast ZAMAK gears, maybe if they were steel.

Anyway will get 6 to 1 via the back gears but even that may still be too fast,

 

[Gritineye]

I would say that you'll need to preheat this, one to minimise distortion/warping, two because you've got that cast iron/steel hub, you want everything to be nice and plastic (ductile). Once welding, you'll need decent amperage, i'd think 180+ amps, to keep the heat in.

If you get stuck. Bring them up to me, Id set them set up on the semi-automated positioner. Sussex isn't a million miles away.

Could even skim them if they're too small for your lathe.

The whole thing is a steel stamping/pressing, you may just have talked yourself into a job!

 

[dyno-tron]

If you end up welding a strip (rather than getting a piece of tube) you may want to consider a slash joint (scarf??), that way you won’t get a clonk clonk clonk at the joint.

 

[PhillipM]

Maybe worth skimming the hot rolled surface off after and then heat soaking the part too before a finish pass, it'll warp from the brake heat after a while otherwise, exhibit A, my brake discs

 

[sako243]

11" x 2:1/4" x 5/32" (it's American) or approx 280 x 60 x 4mm.

There are no unworn areas to measure so thickness is a guestimate. Figures aren't my strong point.

Would an 11" brake drum off a series Land Rover be usable? @Wildefalcon is the resident Series expert. The only ones I have to hand are on the Sandringham which being a Stage 1 / Sandringham has bigger brakes than standard. There are 2.25" wide shoes available (and I think they did a 3").

 

[Gritineye]

Would an 11" brake drum off a series Land Rover be usable? @Wildefalcon is the resident Series expert. The only ones I have to hand are on the Sandringham which being a Stage 1 / Sandringham has bigger brakes than standard. There are 2.25" wide shoes available (and I think they did a 3").

Good call Sako

I have been looking at them on line, I have a LR dealer friend but not got around to taking mine over and having a proper look in his sheds for a direct comparison yet. If anything's available his lads will know for sure.

The main problem is I need 11" OD maybe a 10" one might work, dunno till I have a look.

 

[sako243]

Don't forget the handbrake drum is another possibility.

 

[Wildefalcon]

I'll measure up when I'm back in blighty. On a waterbus in Venice at the mo.

 

[Wildefalcon]

Standard 10" drums (genuine, original swb):

OD is 10.75" ish.

ID is, well, 10".

Brake contact width is 2 1/8"

Offset from mounting flange to start of brake width is 1 1/8"

Aperture is 4 1/2"

Max of hub 8 1/8"


Standard 11" drums:

11 1/2

11

2 1/2

1/2

4 1/2

9 1/2

I can measure some stage 1v8 and some 101 one tonne, just not yet.