Author Topic: Sweet Pea build  (Read 21186 times)

Offline FKreider

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Re: Sweet Pea build
« Reply #15 on: January 19, 2021, 03:39:16 AM »
Thanks Frank

Unfortunately square stainless is not available here so the choice is waste and machine round down to square or use another metal. I will have to get the nickel plating kit out.

Cheers

Julian

I would really like to try nickel plating myself sometime!
-Frank K.

Offline Barneydog

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Re: Sweet Pea build
« Reply #16 on: January 19, 2021, 10:19:49 AM »
Hi Frank,

If you have access to Engineering in Miniature mag over the past few months Rich has written three articles. One part was on the nickel plating process we both use. I am sure it was EIM. If not I am sure Rich will put us right. Once I do some plating on this build I am happy to detail the process and show the results. It won't be yet as I have some bits to continue with for now.

Cheers

Julian

Offline Admiral_dk

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Re: Sweet Pea build
« Reply #17 on: January 19, 2021, 11:31:29 AM »
Chris Rueby has a nice article on our site that do NOT involve any problematic chemicals ...

Offline crueby

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Re: Sweet Pea build
« Reply #18 on: January 19, 2021, 09:23:08 PM »
Chris Rueby has a nice article on our site that do NOT involve any problematic chemicals ...
Yup, its pretty simple to do, only needs a small power supply like a electric device uses (printer, phone, etc), 5 or 6 volts and 1 amp will do. The solution is no stronger an acid than household vinegar and salt, no nasty chemicals (still dont want to drink it! ). I've used it on a bunch of parts, very handy. There are places that will sell you a very expensive kit, totally not needed, only specialty item is a piece of pure nickle, I got a rod of it off Amazon. A copy of the article with a little more detail will be in one of the upcoming Live Steam magazine issues too.

Offline Barneydog

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Re: Sweet Pea build
« Reply #19 on: January 19, 2021, 09:40:15 PM »
Thats the kiddy. Only white vinegar, salt and electricity. We been using  it for a while. Rich wrote article in eim mag.

Cheers

Julian

Offline JC54

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Re: Sweet Pea build
« Reply #20 on: January 20, 2021, 10:22:44 AM »
Hello, I have a Metre Maid the 6 wheel version (060) of Sweet Pea that is fully running/Boiler tested but am intending to refurbish when time permits. I will be following your build with great interest. Can't wait for the valve mods. I intend to  made changes to the controls to improve my driving position due to health problems. The change of regulator sounds a good idea as mine apparently always leaks a bit at steamtest so I am informed. I have tried the Nickel coating system as shown in Engineering in Minature and Chris, very simple to do and lovely results. All the best with this build. :old: :DrinkPint: :DrinkPint:
                               John
When the Fun Stops,, Stop!

Offline Barneydog

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Re: Sweet Pea build
« Reply #21 on: January 20, 2021, 11:25:54 AM »
Thanks John,
The motion mod I am doing would be very hard to do on a completed loco as you need to drill and tap holes in a couple of the axle boxes to fix the new support plates on. If you can get at them or fit the plates in some other way to the axle you could do it. I am ok as this is a build from scratch so it can be incorporated in the build. Another alternative is to convert to walchaerts. In November 2019 two articles by a bloke called Frank appeared in Model Engineer mag. Certainly worth a look and is certainly a standby option for me.

I have arthritis  on my thumbs that is getting worse so i am going to change all the controls on this loco to make them easier to use and more accessible. I struggle with standard globes so a bit of experimentation to come for the style, siting and design of them. Got several ideas that need looking at. They need to be looked at early in the build as they may change some of the earlier work.

Cheers

Julian

Offline Barneydog

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Re: Sweet Pea build
« Reply #22 on: January 20, 2021, 01:10:07 PM »
Hi Guys,
A quick update on yesterdays work before I go outside to carry on.
The halves of each box need fixing together in their final positions so they can be machined.

Top face of the top halves were marked and centre punched ready for drilling. I drilled them with a 4mm cutter in the mill so the holes were straight and square to the faces.

I clamped the halves together in the vice to hold them square and aligned. I put a 4mm drill trought each hole to mark the top of the bottom halves.

Drilled 3.2mm ready for tapping to M4. The tape on the drill is set at about 10mm as a depth guage. The tapping does not need to go all the way through as two of them need extra holes drilling and tapping later.

All four sets were bolted together with some M4 capheads ready for machining. These bolts are temporary. They will be replaced later with some spring guides that will replace them to both guide the springs and clamp the halves together.




Axle box number one was set up in the lathe to drill and bore centrally. They do not need to be absolutely dead centre but they do all need to be the same from scribed edge and the top t5o the centre of the bore.
The box was drilled and then bored to 19mm. The tape covering two of the four jaws keyways was put on to stop these jaws being accidentally moved. All for boxes were bored the same. Only two jaws were moved to swap them over so they should all be identically bored.

Last job was to drill a hole on the top for oiling the faces when in use. All were drilled 5.6mm for a depth of about 7mm. The n I drilled at an angle towards the middle with a 1.7mm drill through into the bore. The 5.6mm hole was tapped to 1/4"x40 ready for either an automatic oiler or extended oil cups to be screwed in later.


Last job of the day was a trial fit in the horns. Very pleased with the fit-not too tight but not too loose. The edges were chamfered slightly to allow them to tilt slightly to allow for suspension movement. This was a simple filing job. No need for the mill here.

Cheers

Julian

Offline Barneydog

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Re: Sweet Pea build
« Reply #23 on: January 20, 2021, 08:03:51 PM »
Hi Guys,
Had a few productive hours outside today.
Since the hornkeeps are off at the moment I set up my nickel plating and gave them a quick do just to stop them rusting. They may get another layer later or be painted but that is for later. At least they are protected for now.
The acetate solution is just white vinegar and a bit of salt. It has gone green because to prepare it nickel was disolved into it by electrolysis. To plate items two blocks of nickel are suspended in the solution on titanium wire, connected together and attached to the positive of my 5v power supply. The items to be plated are connected to the negative and suspended in the solution on titanium wire without touching the nickel and its wires. Power is switched on and the nickel passes across from the positive nickel blocks to the negative items to be plated.

The bubbles are the electolysis happening. Twenty to thirty minutes will do for now.

Today I needed to machine the axles. My wheels were partly machined by the previous owner. The holes in the middle were not bored to the required 5/8" but luckily were all near enough the same size about 17.8mm.
Because of this I have bored the holes in the axle boxes to 19mm to allow a step for the wheels to sit against. I had a small bit of 19mm mild steel bar but was short by a couple of inches. Luckily Rich had some I could scrounge.

I cut two lengths to just over the required length of 6 1/8" to allow some cleaning up.
I have a very accurate collet system on my lathe so did not need to turn between centres.

I turned one end to the correct fit for a wheel. I then measured from the step it sits against 4 5/8". This is the required measurement on the plans for the distance between the backs of the wheels. I turned the other end to this make to fit another wheel. Because there is a very small difference in the boring of each wheel I have turned the ends to match a wheel and then marked the ends and a wheel for each.
I turned the middle of the front axle down by a millimetre to give clearance if it is needed at a later date. The rear axle was turned down to leave an island in the middle for the pump eccentric. This island was left at 19mm. Here are the two completed axles. This steel we acquire some years ago generally turns very well but occasionally turns a rough patch like in the middle of the front axle. Luckily it is in the middle and not on a bearing surface. Turn well under power on my lathe.

Sitting in the axle boxes with the wheels on. The frames are upside down still.

Next job is to make a jig, turn the faces and treads of the wheels and turn the crank pins.

Cheers

Julian

Offline Firebird

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Re: Sweet Pea build
« Reply #24 on: January 20, 2021, 08:51:14 PM »
Turned out nice  :ThumbsUp:

Cheers

Rich

Online Kim

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Re: Sweet Pea build
« Reply #25 on: January 20, 2021, 08:58:22 PM »
That Nickle plating seems pretty neat.  I may have to find a reason to try that someday!
Kim

Offline Barneydog

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Re: Sweet Pea build
« Reply #26 on: January 24, 2021, 09:14:58 PM »
Thanks Rich.

Thanks Kim.
It is good but does not need much voltage. I need to put a voltage regulator to take my 5v down to about 3v otherwise it can burn the surface of the metal to be plated. Best slow and gentle.

Not had a chance to get into the workshop as much as I would have liked. My 86 year old mother tripped at home and ended up in hospital on thursday evening. She has broken her hip so had to have an opp on friday. In hspital on her own as no visitors allowed for at least the next week or two. My Dad has Parkinsons so cannot be left on his own. We are sharing the duties between my wife and my sister. I am doing some repairs at our shop while it is closed hence workshop time may be limited for a while.

Got four hours outside this afternoon so made the jig for turning the wheels.
Turned a short length of mild steel in the collet holder. It is a short bit of the axle material 19mm diameter. Turned it down to fit the bored hole in the wheels. The reduced bit is enough to go through the jig blank hole of about 14mm and enough to thread for a holding nut.

Allowed a shoulder big enough to almost go through the jig blank but short by a couple of mills. The rest of the stub was reduced to 10mm and tapped M10

Cut off the bar with enough to go most of the way through the wheel.

Next in the three jaw chuck started with a circular steel blank smaller than the wheels but thick enough to project beyond the jaws of the chuck. Faced both sides just to clean it and square the faces.

Next I marked the face with all the holes needed. A small centre drill in the centre. Fron this hole I used a compass to draw two circles at 1" and 1.25" from the centre. One hole is made on the 1" mark and then at 90 degrees two holes 180 degrees apart are made on the 1.25" circle

The holes on the 1.25" circle are drilled 5mm and tapped M6. The 1" circle hole will be fully drilled later when it is needed. For now it is a 5mm hole 2mm deep ready for centring later in the four jaw and drilling to size. Next the centre hole was drilled and then bored for the shoulder on the previus part to be fitted in with a tight fit.

Next a nut and washer were used on the back to secure it in place. The front of this stub was then turned down until the wheels will fit on with a decent fit that will stop movement but allow the wheel to be removed. The final cut was brought out across the face of the disk to square it with the stub. From now on the jig CANNOT be moved in the chuck until ALL four wheels have been machined. This ensures they are all identical.

You will see that the wheel castings have two holes cast into them. These were drilled out to 10mm. A wheel was mounted on the jig with two M6 bolts through these holes screwed into the two holes tapped in the jig.


The wheel is now ready for machining to size. To give a nice surface I used a small round insert tool. First the face was turned down to the required thickness of 3/4"

You may notice this picture has a triangular insert but the surface was improved with a round one so all further machining was done with this tool.
Next the tread was turned down to the design diameter of 4.25". Luckily the insert used matched the curve needed at the base of the flange. The flange had a very small shave to ensure it was uniformly 4 5/8".

Last job was to shape the top of the flange to a nice curve without altering its size too much.

Once completed the wheel was removed and tried on its axle. I can see the axles will need shortening to fit the machined wheels before they are fixed and quartered. Repeated this procedure with another wheel today. Next chance I get I will complete the other two then we can get on with the crank pins using the same jig in a four jaw.

Cheers

Julian

Online Kim

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Re: Sweet Pea build
« Reply #27 on: January 25, 2021, 05:20:44 AM »
Very nice, Julian!
You're going to be done with your wheels long before I am.
Are the wheels going to be left solid? Or will you be milling out some spokes?

Kim

Offline Barneydog

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Re: Sweet Pea build
« Reply #28 on: January 25, 2021, 08:06:17 AM »
Hi Kim,
Leaving them solid. Because its based on functional shunting engines I think they look better solid. This is an 042 so the rear donkey wheels are very visible. They will be easier to turn rather than mill. I have made wheels on my cnc mill in the past which looked ok but on this occasion they will be solid. I intend extending the saddle tank forward to the front of the smokebox. I think solid wheels will add to it looking a bit of a beastie!!!

Cheers

Julian

Offline Barneydog

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Re: Sweet Pea build
« Reply #29 on: January 26, 2021, 07:22:43 PM »
Hi Guys,

Had a productive afternoon in the workshop today. I continued on from yesterday and finished machining the remaining wheels. Got a nice finish with the round tool. At a later date they will go back in the three jaw to be buffed up with wet and dry. I will leave the tread as it is to give a little more grip.

Now all four wheels have been machined the jig is removed and transferred to the four jaw chuck. The centre is used to align the hole on the 1" mark. This makes the jig offset by 1".


Again now the jig is in the correct position it will NOT be moved until all four wheels are finished. The hole is now progressively drilled until it is 9/16". This really is the minimum so because it was handy I drilled out to 16mm. The hole needs to give clearance for a 1/2" reamer.

All the wheels are marked with a line through the centre of the axle hole and centrally up the crank pin lobe. A wheel is then fixed to the jig with the centre on the marked line. All four wheels will be fitted in the same way so all the holes are  in the same position on each wheel.

The centre was then swapped for the drill chuck and the hole is drilled with several drills until it is just under 1/2" and is then reamed with a machine reamer. I used my slowest speed on my lathe of about 60rpm because the jig and wheel are off balance. I also did not want to rip or vibrate the wheel and jig out of the chuck.

All four wheels are done the same.

The jig can now be removed. It has done its job so hopefully will not be needed again.
The four jaw is swapped for the ER25 collet holder. Its now time to machine the crank pins for the wheels. The book says use 11/16" silver steel or if necessary mild steel. I have no silver steel so my choice is steel or stainless steel. I have no stainless that size so would have to machine it to size. I have nothing near that size in 303 which is easier to machine than 304. I have some steel the exact size needed from my stock that came from the same source as the axles. It is quite a hard steel that machines ok but does need some care to get it smooth. It chatters very easily.

Here is the first one done. The 1/2" end on the right of the photo was turned to an exact fit for its wheel. The centre of this face is relieved a little to leave space for the loctite. I will number them so they stay together. The bearing faces for the con rods were cut with my parting tool. These faces were cleaned up with a strip of wet and dry with some oil for lubrication. The whole pin was then parted off. Fits nicely in its wheel. Three more to go on another day.


Cheers

Julian



 

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