Building a Caledonian Pug in S Scale
- Thread starter JimG
- Start date
JimG
Western Thunderer
Scott,
It actually doesn't take all that long. I thought it would take a fair time to do but I think I had the job done in about 10 to 15 minutes. I didn't time myself, so that's a guess.
The scraper does the lion's share of the work and the sandpaper smooths off the rough edges.I'm also trying to work out a building system for the wheels and chassis that I can use in future locomotives - a knock-on from the discussion we had a while ago on frame widths in S scale on RMWEB. So I'm trying to set up a set of bits and pieces which can be used in any further locomotives I build which will also have a built in ability to allow for side play, which I will need to get round the curves in Banavie Road. More on that as I go along.
More work on boring out the ring chuck on the ML10 today. The garage gets extremely hot and stuffy in this very good weather and I have to work with a fan blasting (slightly) cooler air at me from behind the tailstock, so I can only stand this for short bursts.
Jim.
JimG
Western Thunderer
I got the ring chuck finished this afternoon.
This is the business end with recesses for 1" and 1 1/4" blanks (see later.)
..and the back end showing the reduced section to fit in the centre of the Cowells' three jaw - this to give a fair length to allow spring action. The turned part was marked out at 120 degrees in the ML10 using the jaws of the three jaw against a spacer from the bed to get the displacement and a tool racked across the piece to make a mark. Three holes were then drilled to mark the ends of the slits and the slits were sawed with a Junior hacksaw. One of the cuts is not quite radial - a result of my lifelong fight to get accurate cuts with Junior hacksaws. However, this errant cut doesn't affect the operation of the chuck.
And the reason for the chuck is here
...a box full of mostly 1" and 1 1/4" diameter mild steel blanks which I got my hands on at the S Scale AGM earlier this year. According to John Holden, the Parts Officer at the time, he had been given the box some time ago by another member and he had left them out on the table to see if anyone was interested. I think they might have been made to produce S scale steel tyres since most of the blanks are 3/32" thick which is just right for S scale allowing a few thou to finish to thickness.A quick donation to the SSMRS funds was negotiated and I've now got enough blanks to keep me going in loco building till who knows when.
The ring chuck in use on the Cowells with a 1" blank about to be faced and bored for the wheel centre. There is no real need for absolute concentricity since the tyre profile will be finish turned on the wheel centre mounted on a accurately set up spigot.
Jim.
This is the business end with recesses for 1" and 1 1/4" blanks (see later.)
..and the back end showing the reduced section to fit in the centre of the Cowells' three jaw - this to give a fair length to allow spring action. The turned part was marked out at 120 degrees in the ML10 using the jaws of the three jaw against a spacer from the bed to get the displacement and a tool racked across the piece to make a mark. Three holes were then drilled to mark the ends of the slits and the slits were sawed with a Junior hacksaw. One of the cuts is not quite radial - a result of my lifelong fight to get accurate cuts with Junior hacksaws.
However, this errant cut doesn't affect the operation of the chuck.And the reason for the chuck is here
...a box full of mostly 1" and 1 1/4" diameter mild steel blanks which I got my hands on at the S Scale AGM earlier this year. According to John Holden, the Parts Officer at the time, he had been given the box some time ago by another member and he had left them out on the table to see if anyone was interested. I think they might have been made to produce S scale steel tyres since most of the blanks are 3/32" thick which is just right for S scale allowing a few thou to finish to thickness.A quick donation to the SSMRS funds was negotiated and I've now got enough blanks to keep me going in loco building till who knows when.
The ring chuck in use on the Cowells with a 1" blank about to be faced and bored for the wheel centre. There is no real need for absolute concentricity since the tyre profile will be finish turned on the wheel centre mounted on a accurately set up spigot.
Jim.
JimG
Western Thunderer
If you need any blanks....
. I don't think I will use a quarter of this box full in my remaining lifetime. Jim.
ScottW
Western Thunderer
If you need any blanks....
Thanks Jim. I'm looking at making a few wheels soon for some future projects., I'll have a think about how many I'll need and get back to you.
Scott
D G Williams
Active Member
A query about the ring chuck. I have made one to hold a wheel following Tevor Nunn’s article in a past S Scale Gazette, and another to hold one-eight silver steel for axles. Both of them have one slit and they have to be put back in the 3-jaw chuck in the same position every time. Your ring-chuck has 3 slits. Does that allow it to be put back in the chuck in any position?
David
David
JimG
Western Thunderer
David
I didn't make the ring chuck to be concentric knowing that I didn't actually need concentricity to handle the facing and boring of the tyre blanks. And I would be doing all the turning on the Burnerd three jaw on my ML10 and finishing up using it on the small Bison three jaw on the Cowells, so there would be little chance of matching the runouts on both chucks. (The Burnerd is actually very good considering it is over forty years old and it is only about two thou out.) If I had wanted it concentric then I would have to have finish turned the ring seatings on the Cowells' chuck and I would still have needed to match the cutting position to the chuck jaws to guarantee concentricity since the possible run-out errors are in the chuck itself.
I opted for three slots rather than one since I was worried that there might not be enough give with one slit. I would normally do the same as Trevor and use one slit, which I am just about to do for a holder for the wheel centres to finish drill and ream the axle holes.
I'm intending making the spigot holder for finish turning the wheels to be held in the four jaw so that I can adjust that to be spot on.
Jim.
D G Williams
Active Member
Thanks for that! Mention of the 4-jaw makes me wonder if a ring chuck could be made in the 4-jaw and re-set with the help of the 'clock'? I can't see why not, but I'll bet there's a hidden sang ...
David.
JimG
Western Thunderer
David,
I think that it might be a bit of a juggling match in the four jaw - i.e. tightening the jaws to compress the holder and also adjusting the jaws for concentricity. I'm not saying it's impossible, but I think I might prefer a three jaw.
The advantage of the three jaw is that, even with its inherent errors, it should tighten up to the same position repeatedly.I've just finished making the next split chuck to hold the wheel centres. This time it's the normal single slit with mark to match No.1 jaw for accurate, concentric holding.
It was roughed out on the ML10 for speed - I can whack a 5/8" drill through the piece on that lathe to get my bore quite quickly.
This is the roughed out version in the Cowells' chuck with the No.1 jaw mark already made. I found out the hard way many years ago that leaving making the mark till later could be a problem if you forgot and took the piece out of the chuck to do something before making the mark.
The outer surface has been turned true just in case I ever want to check it later. You can just see the inner recess for the wheel centre - it's quite shallow since there has to be clearance for the protruding balance weight when the centre is mounted rear outwards.
...and the finished piece after all the turning, but before the slit was cut.
The holder is now back in the chuck with the wheel centre being held (slit to the bottom opposite No.1 jaw). I found that the holder actually closed up a bit as I was sawing the slit which made life a bit difficult to complete the cut.
I never remember that happening to me before. It means that I've got to prise the jaws apart slightly with something like a fine screwdriver to get the wheel centres in, but at least they don't fall out of the holder now. I'm now just about to open the axle hole out to 3.1mm then finish up with a hand reamer so that the taper end of the reamer leaves a taper in the axle hole to provide a press fit for an 1/8" axle. I'll also make a collar up to lock on the reamer once I've found the amount to feed it in, so that I can repeat it with other wheels. The collar will be made out of brass with a brass locking screw.
Jim.
S
Simon Dunkley
Guest
This would only work if you pretty much left the chuck alone between uses, and only moved two of the jaws, e.g.1 and 2.
Well, it wouldn't only work that way, but it would take so long to set it up each time, that you would regret not using the 3-jaw and making a small mark on it.
And the point about the pop mark for jaw 1 is that you will be returning the split chuck to the same place in the 3-jaw each time, thus ameliorating the inherent errors.
Another option might be to use a collet chuck (those preferring older designs might use a Dean or even a Gooch chuck), but it would need to be of a reasonable size, possibly ER32 or ER40.
Two lathes. One in the house (a Cowell's, too), one in the garage.
There's posh for you.
Being more of a bodger, I have had success opening up in stages to 3.1mm, then using a 3.15mm drill, turning the chuck very carefully by hand, to create an interference fit.
Incidentally, many years ago I had a lot of success turning brass centre castings to fit into Alan Gibson steel tyres using a Unimat SL, so a machine sturdy enough to use a form tool on steel is not an absolute requirement for making S scale wheels.
Looking at the plastic trial, Jim, it struck me that these could be used to produce masters from which a mould was taken, and sub-masters produced in lost-wax brass, if you get my drift.
Simon
JimG
Western Thunderer
When my wife passed away three+ years ago, there was talk of my daughter getting a bigger house and me possibly moving into a "grannie" apartment in the house so I started planning for such a move by getting desktop machinery - Cowells and KX1 mill - in case there wouldn't be space for a workshop to house the ML10 and the Centec mill. The house plans didn't come to pass, so I've now got an inside workshop - all metric - and the original outside workshop in the garage - all Imperial. So I have to switch the brain into metric or Imperial as I walk up or down the path to the garage. I've actually got a reamer which cuts a push fit for 1/8" but I started using hand reamers in 7mm wheels some years ago and I preferred that I could get a short length of full size in the hole, before the taper starts, to locate the axle properly before the push fit. This allows me to partially engage the taper to fine adjust the quartering before pushing wheels fully home.
Maybe if I was starting afresh I would aim to use the Society machined tyres and machine everything to suit them, but I got myself a form tool so I feel I have to justify the £70.
My original intention with the KX1 mill was to make masters for lost wax casting and I have a supply of blue machining wax to use as a master material which burns out in moulds. But I reckon I can probably turn out the six wheels required in one or two days when I've got all the holders made, and a fair chunk of that time would be the turning which would also be required for wheel centre castings. However if anyone else in the Society showed interest in any wheel I made, then casting from a master would probably be the way to go for them.
I'm now off to ream the wheel centre so that I can make the spigot to hold the wheel for finish turning. I lost most of the afternoon doing short notice taxi service for the family.
Jim
JimG
Western Thunderer
Well, it’s been a week and I’ve got a finished wheel at last. I hate working in a sweltering, hot workshop and life was only made bearable by having a fan blasting at me.
I started making the holder for the finish turning of the wheel. I wanted a recess in the end so I started off with a bit of 1” steel and cut the recess in the end, then bored it 5mm to take the spigot.
At this point there was a small diversion. The inside workshop had grown like Topsy over the past three years and it was becoming a problem finding a place to put things down and then finding them again at a later date. The hot weather brought things to a head at the weekend, so the shelves appeared.
Now I could find everything - especially the Erikson collets which had been stored in the individual poly bags which they came in from Cowells.
Before I could turn the spigot, I had to know the diameter of the hole in the wheel centre so I proceeded with drilling the centre 3.1mm then opening it out with a 1/8” hand reamer
The hand reamer has a slow taper on its end which helps with starting. If you ream a hole with a hand reamer and get the transition from taper to parallel within the hole, then axle material can be entered for the parallel part of the bore, then requires pressure to push through the taper part of the bore, giving a push fit. I made a collar to fit the reamer then entered the reamer about 0.25mm at a time and tested with a piece of axle material until the material entered by about 1mm. When this point was reached, the collar was butted against the wheel back and locked in place 3with the screw.
This shows the wheel and axle from the other side, showing the distance left for force fitting
While the centre holder was in the chuck, I also turned the 0.3mm boss on the back of the wheel
I then started on the spigot using a nice piece of steel rod salvaged from an old Epson printer. This was the 5mm diameter part which would fit in the main holder part. The brown colour on the steel is the cutting fluid I'm using, applied with a brush. It stinks.
The part was then reversed in the collet chuck and the spigot end turned to size to be a nice fit in the reamed axle hole in the wheel centre. I did this by making the spigot over length then got the whole spigot near to size at 3.2mm then turned a short length at the end down by 0.01mm at a time until the wheel fitted. If the fit was too loose, then I brought the tool back by under 0.01mm on the next few millimetres in on the length until the wheel fitted snuggly, then cut the whole length to that diameter. I then cut the spigot to length and drilled the spigot 1.8mm for tapping an 8BA hole for the screw.
I then tapped the 8BA hole using the tailstock and tap holder to make sure it started square.
I then fixed the tyre to the wheel centre using two small patched of 188 solder paint, and my Weller 100W iron to get it done quickly.
The spigot was fitted in the main body of the holder using cyanoacrylate glue. I also fitted a peg (from a turned down 10BA screw) to engage with the spokes of the wheel centre since the forces in turning tyres with a form tool can be quite large and the peg would be needed to deal with them. note the first attempt which was too near the rim.
This was the first version of the spigot, where the spigot was split and the tapped hole was only partly cut with a taper tap so that a screw would open out the split and lock the wheel when the screw was tightened. This didn’t work as well as I had hoped, so I made a second version which used a collar to hold the wheel in place.
The second spigot is now in the holder body and the screw and collar are on the lathe topslide.
This is holder being set up to run accurately in the four jaw chuck using the dial test indicator.
I'll now have to continue on another message to finish off the pictures since I've hit my limit.
Jim.
I started making the holder for the finish turning of the wheel. I wanted a recess in the end so I started off with a bit of 1” steel and cut the recess in the end, then bored it 5mm to take the spigot.
At this point there was a small diversion. The inside workshop had grown like Topsy over the past three years and it was becoming a problem finding a place to put things down and then finding them again at a later date. The hot weather brought things to a head at the weekend, so the shelves appeared.
Now I could find everything - especially the Erikson collets which had been stored in the individual poly bags which they came in from Cowells.
Before I could turn the spigot, I had to know the diameter of the hole in the wheel centre so I proceeded with drilling the centre 3.1mm then opening it out with a 1/8” hand reamer
The hand reamer has a slow taper on its end which helps with starting. If you ream a hole with a hand reamer and get the transition from taper to parallel within the hole, then axle material can be entered for the parallel part of the bore, then requires pressure to push through the taper part of the bore, giving a push fit. I made a collar to fit the reamer then entered the reamer about 0.25mm at a time and tested with a piece of axle material until the material entered by about 1mm. When this point was reached, the collar was butted against the wheel back and locked in place 3with the screw.
This shows the wheel and axle from the other side, showing the distance left for force fitting
While the centre holder was in the chuck, I also turned the 0.3mm boss on the back of the wheel
I then started on the spigot using a nice piece of steel rod salvaged from an old Epson printer. This was the 5mm diameter part which would fit in the main holder part. The brown colour on the steel is the cutting fluid I'm using, applied with a brush. It stinks.
The part was then reversed in the collet chuck and the spigot end turned to size to be a nice fit in the reamed axle hole in the wheel centre. I did this by making the spigot over length then got the whole spigot near to size at 3.2mm then turned a short length at the end down by 0.01mm at a time until the wheel fitted. If the fit was too loose, then I brought the tool back by under 0.01mm on the next few millimetres in on the length until the wheel fitted snuggly, then cut the whole length to that diameter. I then cut the spigot to length and drilled the spigot 1.8mm for tapping an 8BA hole for the screw.
I then tapped the 8BA hole using the tailstock and tap holder to make sure it started square.
I then fixed the tyre to the wheel centre using two small patched of 188 solder paint, and my Weller 100W iron to get it done quickly.
The spigot was fitted in the main body of the holder using cyanoacrylate glue. I also fitted a peg (from a turned down 10BA screw) to engage with the spokes of the wheel centre since the forces in turning tyres with a form tool can be quite large and the peg would be needed to deal with them. note the first attempt which was too near the rim.
This was the first version of the spigot, where the spigot was split and the tapped hole was only partly cut with a taper tap so that a screw would open out the split and lock the wheel when the screw was tightened. This didn’t work as well as I had hoped, so I made a second version which used a collar to hold the wheel in place.
The second spigot is now in the holder body and the screw and collar are on the lathe topslide.
This is holder being set up to run accurately in the four jaw chuck using the dial test indicator.
I'll now have to continue on another message to finish off the pictures since I've hit my limit.
Jim.
JimG
Western Thunderer
And continuing......
The tyre has been turned down close to its maximum diameter over the flange then the topslide has been set over to rough turn the tyre profile at three degrees - i.e. the flange is square in shape. I prefer to turn my tyres this way when using a form tool so that the form tool finishes up, basically, forming the flange and flange/tyre transition, so has comparatively light forces. The main tyre forming is done by the lathe tool running normally, again with comparatively light loading on the lathe.
Now the form tool has been used to get the finished tyre profile.
Two shots of the finished wheel, the second one fully pushed on to the test axle to check out the push fit - and it feels right.
One thing I forgot was to machine off the boss to its correct depth - it should be flush with the balance weight.
I'm also going to machine the boss on the back of the wheel to be 0.5mm deep so that the rear of the wheel centre is recessed into the tyre. This will give a small ledge on which the solder paste can sit for fixing the wheel. The 0.3mm deep boss meant that the back of the wheel centre was flush with the tyre and the solder paint had to be put in the recess in the tyre, which actually affected the seating of the centre in the tyre. It will also avoid solder appearing on the front of the wheel - i.e. between the tyre and the balance weight.
Also, the cyanoacrylate glue in the spigot did not work - in both types of spigot. In the first spigot, I thought that my bottle of Hafix might have passed its sell by date, having been left out of the fridge by mistake, when the spigot came loose when tightening the screw. When I fitted the second spigot, I got a new bottle to do the job, but the same problem happened, even after full cleaning before sticking. I then remembered that cyanoacrylate needs some space to work and my fit on the spigot was a light push fit - i.e. with virtually no space for the glue. So I bodged a push fit by tinning a thin coat of solder round part of the spigot and it worked beautifully with a good push fit.
You can just see the tinned section on the right hand part of the spigot.
Now I think I can get on with the six wheels for the loco with everything worked out.
Jim.
The tyre has been turned down close to its maximum diameter over the flange then the topslide has been set over to rough turn the tyre profile at three degrees - i.e. the flange is square in shape. I prefer to turn my tyres this way when using a form tool so that the form tool finishes up, basically, forming the flange and flange/tyre transition, so has comparatively light forces. The main tyre forming is done by the lathe tool running normally, again with comparatively light loading on the lathe.
Now the form tool has been used to get the finished tyre profile.
Two shots of the finished wheel, the second one fully pushed on to the test axle to check out the push fit - and it feels right.
One thing I forgot was to machine off the boss to its correct depth - it should be flush with the balance weight.
I'm also going to machine the boss on the back of the wheel to be 0.5mm deep so that the rear of the wheel centre is recessed into the tyre. This will give a small ledge on which the solder paste can sit for fixing the wheel. The 0.3mm deep boss meant that the back of the wheel centre was flush with the tyre and the solder paint had to be put in the recess in the tyre, which actually affected the seating of the centre in the tyre. It will also avoid solder appearing on the front of the wheel - i.e. between the tyre and the balance weight.
Also, the cyanoacrylate glue in the spigot did not work - in both types of spigot. In the first spigot, I thought that my bottle of Hafix might have passed its sell by date, having been left out of the fridge by mistake, when the spigot came loose when tightening the screw. When I fitted the second spigot, I got a new bottle to do the job, but the same problem happened, even after full cleaning before sticking. I then remembered that cyanoacrylate needs some space to work and my fit on the spigot was a light push fit - i.e. with virtually no space for the glue. So I bodged a push fit by tinning a thin coat of solder round part of the spigot and it worked beautifully with a good push fit.
You can just see the tinned section on the right hand part of the spigot.
Now I think I can get on with the six wheels for the loco with everything worked out.
Jim.
JimG
Western Thunderer
Jon,
I reckon it would withstand a lot of force provided the temperature of the materials didn't get anywhere near its melting point and I doubt if I could generate that sort of heat on a Cowells lathe.
At normal ambient temperatures, I would expect the solder to be many times more than strong enough.Jim.
Steve Cook
Flying Squad
An excellent thread Jim
Thanks for taking the time to show the amount of work that goes into producing a set of wheels, its an eye opener for me to see all of the individual steps you've gone through before you've even got a finished wheel to show for it - I have no doubt that the finished wheels will justify the effort we've seen though
Steve
Thanks for taking the time to show the amount of work that goes into producing a set of wheels, its an eye opener for me to see all of the individual steps you've gone through before you've even got a finished wheel to show for it - I have no doubt that the finished wheels will justify the effort we've seen though
Steve
