Don Young's Black 5

[gwr14xx]

Hi Brian,
Turning operations involving an interrupted cut are another example of jobs that lend themselves well to running the lathe in reverse with the tool inverted - give it a try, I think you will be surprised how much smoother the tool cuts! (Sorry Roger if the thought brings you out in boils, but the advantages far outweigh the disadvantages!)

Regards,
Eddie.

[Roger]

Mar 26, 2019 12:43:01 GMT gwr14xx said:

Hi Brian,
Turning operations involving an interrupted cut are another example of jobs that lend themselves well to running the lathe in reverse with the tool inverted - give it a try, I think you will be surprised how much smoother the tool cuts! (Sorry Roger if the thought brings you out in boils, but the advantages far outweigh the disadvantages!)

Regards,
Eddie.

Hi Eddie,
I'm a fan of anything that works, even if it's technically horrible.

[Jim]

To add to Pete's very sound advice I might add that with the set up you are using the bore tends to taper as the tool deflects due to the long over hang. With Pete's method the boring bar is supported on both ends and is more substantial giving you a parallel bore.

Jim

[JonL]

Just to put my oar in, I notice Brian mentions that this is the roughing cuts, so as long as the critical dimensions are not hit its a good quick way of removing metal prior to boring between centres. Adjusting the tool on a between centres boring bar is a bit of a pain!

[runner42]

Thanks for the replies so much advice that I shall put the response in one reply instead of addressing each individually.

Firstly, I am only using the the boring head for roughly boring the cylinder and piston valve bores because of the significant mis-registration between the cored holes and the drawing requirements. I intend to use between centres boring for the final 25 thou or so. Well spotted Nobby.

I shall give running the lathe in reverse and the cutting tool inverted for facing the backs of the wheels. But I am not optimistic that it will work. My reason for saying this is when running the the lathe in the forward direction that the interrupted cuts was effectively hammering the chuck tighter and tighter on to the lathe spindle so much so that I had to have a very long lever to get it off. This type of hammering in the reverse direction is going to unwind the chuck from the spindle and force the tool to dig in.

I don't have powered cross feed being an old type C Southbend lathe so I have to manually operate the cross feed. The size of wheels 6.5" on a 9" swing lathe puts the configuration of the compound slide and the cutting tool in a non optimized position. The cross slide is out to the very maximum that can be obtained, it touches the cross slide handle when starting the cut on the periphery and to prevent the cross slide hitting the chuck the tool overhang is greater than you would like. The backlash in the cross slide and compound causes the tool to be pushed back when reaching the spoked area of the casting.

I have considered using an angle grinder to reduce the amount of metal that I needs to be removed from the back face about an 1/8", but maybe I should consider that the lathe isn't up to it and get someone with a bigger and better lathe to at least do the back face.

Brian

   

[ettingtonliam]

A 6 1/2" wheel on a 9" lathe shouldn't be a problem. You haven't said what the lowest speed is. Backlash in the topslide shouldn't be an issue if you lock the slide, or at least tighten the gib adjusting screws. Is that tool with the trianglar tip the only one you have? Go for the tool set parallel to the bed, minimum overhang.

[David]

Irrelevant now but going back to your initial attempts on the bronze with the big carbide cutter, I had a similar problem two weeks ago although not as bad. I was trying to take a lot of material off a square bronze bar (would be same material as yours probably, also came from EJ Winter) to make axleboxes and had a similar looking result. It was more like rubbing than cutting even though the depth of cut was 1mm. I am guessing the inserts for the cutter were not working on the bronze.

I changed over to a flycutter with an insert suitable for aluminium and it was a different world. 1mm depth of cut was a bit scary and chipped the insert but they have 4 usable edges and going down to 0.5mm depth of cut it gave a beautiful finish. It was about 200 or 300 rpm and a fairly slow feed.

[Roger]

Mar 27, 2019 6:28:25 GMT David said:

Irrelevant now but going back to your initial attempts on the bronze with the big carbide cutter, I had a similar problem two weeks ago although not as bad. I was trying to take a lot of material off a square bronze bar (would be same material as yours probably, also came from EJ Winter) to make axleboxes and had a similar looking result. It was more like rubbing than cutting even though the depth of cut was 1mm. I am guessing the inserts for the cutter were not working on the bronze.

I changed over to a flycutter with an insert suitable for aluminium and it was a different world. 1mm depth of cut was a bit scary and chipped the insert but they have 4 usable edges and going down to 0.5mm depth of cut it gave a beautiful finish. It was about 200 or 300 rpm and a fairly slow feed.

Bronze can be a sod to machine when the edges get dull, because it's a bearing material and the cutting tool would rather rub and bounce off than penetrate the work. That's why the Aluminium inserts are a blessing, because they have a razor sharp edge, even though the geometry is wrong for Bronze. Yes, the sharp edges can be damaged, but that's a secondary issue you can live with if you can cleanly cut the material.
When machining the Leaded Bronze cylinders from solid, as soon as the cutters became a little blunt it became a struggle and they had to be changed.

[runner42]

Made a start on rough boring the cylinder and piston valve bores using the milling machine boring head. However the MT3 taper in the lathe spindle is rats and the taper alone couldn't hold the boring head so I first had to make a draw bar to hold it in securely. I suspect that a lathe draw bar is essential piece of kit anyway. It consisted of a steel rod with a 12 mm 1.75 thread cut on both ends, one end screwed into the boring head's MT3 the other a 12 mm nut to hold the draw bar in position.


lathe drawbar by Brian Leach, on Flickr

I set up the centre of the piston valve bore it being near enough the correct height from the existing bolting face and locked the cross slide. I measured the distance that the cross slide intrudes into the saddle and this is shown as dimension A. The X and Y distances of the cylinder bore to the piston valve bore is 0.25" and 1.75" respectively. Having rough bored the piston valve bore if I add the 0.25" plate between the cross slide and bolting face and increase the distance that the cross slide intrudes into the saddle by 1.75" then I have the cylinder bore and piston valve bore in correct position wrt each other. With these conditions for setup the final boring between centres can be carried out. Then the correct bolting face distance from the cylinder centre can be machined. Some would suggest that the cylinder bore should be used as the reference instead of the piston valve bore if they are correctly positioned wrt to each other then it's broad as it's long.

Brian

boring between centres setup5 by Brian Leach, on Flickr

[Roger]

Hi Brian,
I can't see anything fundamentally wrong in doing the bores this way, it's certainly an advantage to be able to adjust the diameter without faffing about with a micrometer and tapping the tool in and out of a bar between centres.
The disadvantage is that it's not as rigid because the tool is cantilevered from one end rather than being supported from both ends.
In the end whatever gets the job done is fine in my book, I didn't use a boring bar between centres either. You're going to hone it one way or another anyway to get the final finish.

[JonL]

It was pretty quick to make my between centres boring bar, I don't know where you are in the country but you are welcome to borrow it.... EDIT Just realised that you couldn't be further away without leaving the planet! As you were...

[runner42]

Having finished the rough boring of the cylinders I shall turn my attention to making boring between centres tools. I shall probably need two types one for the piston valve and one or the cylinder. The actual cutting bit and its adjustment needs some thinking about, but I am sure there is plenty of examples on the Internet. I was happy with the rough boring it was I what I thought to be a good job in the past. Bore gauges showed good parallelism and no ovality. But I shall use between centres boring just in case.

Brian

Rough bored cylinders by Brian Leach, on Flickr


 

[Roger]

Mar 29, 2019 8:47:47 GMT runner42 said:

Having finished the rough boring of the cylinders I shall turn my attention to making boring between centres tools. I shall probably need two types one for the piston valve and one or the cylinder. The actual cutting bit and its adjustment needs some thinking about, but I am sure there is plenty of examples on the Internet. I was happy with the rough boring it was I what I thought to be a good job in the past. Bore gauges showed good parallelism and no ovality. But I shall use between centres boring just in case.

Brian

Rough bored cylinders by Brian Leach, on Flickr


 

Hi Brian,
That's looking very good. I think I'd have carried on and finished them that way since the result measured what you were looking for and it was all set up.

[stevep]

I agree with Roger.

You will get a parallel bore with the boring head you used, as the overhang is the same all the way through the bore. However, a boring bar would be more rigid, and should be as big as you can comfortably get through the bore.

Remember my tip about having two - with one set to the final diameter, used just for the very last cut. And because it's left unchanged between the two cylinders, they will end up the same diameter.

[ettingtonliam]

Mar 29, 2019 8:47:47 GMT runner42 said:

Having finished the rough boring of the cylinders I shall turn my attention to making boring between centres tools. I shall probably need two types one for the piston valve and one or the cylinder. The actual cutting bit and its adjustment needs some thinking about, but I am sure there is plenty of examples on the Internet. I was happy with the rough boring it was I what I thought to be a good job in the past. Bore gauges showed good parallelism and no ovality. But I shall use between centres boring just in case.

Brian

Rough bored cylinders by Brian Leach, on Flickr


 

If you want good ideas about between centres boring bars, I can recommend Geo Thomas 'The Model Engineer's Workshop manual', pages 92-94.
I can scan these for you if you like.

[dscott]

My second Raglan 5 came with a epic boring head MT 4 so it seems that this lathe will have a Boring life!
The only thing that lets the lathe down is the lack of T slotted Crosslide but I am sure I can get the
Mill to make it one from the odd collection of stuff that got thrust my way after loading it into the car?
If you are wondering about the state of the roads heading north of Weymouth, I offer my apologies!!!

David, and Lily who has perfected swarf removal from various machines!

[runner42]

Finished boring the cylinder and piston valve bore and drilled the bolting faces and fitted them to a cylinder flange for temporary fitting to the chassis. I will probably have to machine the bottom of the cylinders to provide more room for the bottom row of fasteners that fix the cylinder flange to the chassis. Being Springbok castings they appear to have more metal at the bottom. Also, the smokebox saddle obstructs many of the fasteners for the cylinder flange. I have drilled through the saddle and tapped the holes, but because it is a non continuous thread the fasteners bind in the thread. The principle here being analogous to a lock nut's operation. What did DY intend in this area, because the drawing is absent of detail? It appears that some fasteners for the cylinder flange are going to be difficult to access when the piston valve liner and cylinder covers are installed, I would hate to not use the SS hex socket drive screws that I have used extensively and go for a fastener that can be tightened from the side.

Fitting the bare cylinders to the chassis and lifting it for photo taking shows that the weight has significantly increased and I haven't even got the wheels and bogie fitted. I think that for the short term that I trial fit and remove items so the weight is within my capabilities for a 1 man lift.

Brian.

cylinders installed1 by Brian Leach, on Flickr

cylinders installed2 by Brian Leach, on Flickr

cylinders installed3 by Brian Leach, on Flickr

cylinders installed4 by Brian Leach, on Flickr

 

[uuu]

Without knowing DY's intentions, I would suppose you can open the "nutlock" holes in the frame (the ones obstructed by the saddle) out to clearance size, so the frame gets clamped between the cylinder flange and the saddle assembly. Does this sound sensible?

Wilf

[Deleted]

Nice work Brian, those cylinders look made for the loco, very nice work sir..

Pete

[thumpersdad]

Have a look at part 11, page 28 of the build description in "Locomotives Large and Small"

That says that the top row of holes in the flange are in correspond to holes in the smokebox saddle so the saddle is tapped 6BA. The drawings show all the flange to frame fixing holes as 6BA clearance (no. 34).

You seem to have an extra set of screws in the frames above the top of the flange that I can't see on the drawings.

I hope that helps and that I have understood the build description correctly. I don't always find Don Young's explanations very clear.

Eric