Author Topic: Finishing off a 5" Gauge Simplex Loco  (Read 71767 times)

Offline sbwhart

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Re: Finishing off a 5" Gauge Simplex Loco
« Reply #15 on: August 30, 2012, 09:14:21 AM »
Decided to go for it and remove the pinned wheels

 :hammerbash:

Had a good study of the pin through a magnify glass as i was unsure if it was threaded or not, this confirmed that it was threaded but what size took the best measurement i could of it and consulted thread BA thread tables (this guy seemed favour BA) looked like 4 BA, so they by Mk 1 eye ball put a small centre pop in the middle of the pin, then gripping it in a chuck centred the mill on the centre pop, and clamped the chuck to the table centre drill then a No 33 drill (2.8mm) for 4BA core dia then drill the pin out.



A bit more heat from the heat gun and a gentle squese from the puller and off she came   :ThumbsUp:

Repeat for the other two axles, and whilst i was on a roll decided to go for the crank pins that have to come out on the driving axle came out smooth as silk.



A lot happier now   ;D ;D ;D ;D ;D ;D

I can start and put it back together as it should be.

Particularly as I picked up the laser cut links yesterday


Stew
A little bit of clearance never got in the way

Offline doubletop

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Re: Finishing off a 5" Gauge Simplex Loco
« Reply #16 on: August 30, 2012, 10:49:23 AM »
Stew

I do like those laser cut parts and am especially envious of the combination levers. Reading the Don Ashton book on valve gear the combination levers are critical parts and the dimensions matter, especially the pin hole spacing. Mine are slightly different in dimension where they should both be the same for equivalent valve timing. Despite that I think I've got mine set up as well as I could but I really should make two more. Two of those laser cut parts would make it a no brainer and a couple of hours work to finish them.

Quote
(this guy seemed favour BA)

Well that's what the drawings say and the whole thing is drawn in imperial dimensions. Get nuts an bolts from BA Bolts http://www.ba-bolts.co.uk/ They arrive here in NZ within a week of placing an order

Its going to be like a sewing machine when you're done.

Pete
?To achieve anything in this game, you must be prepared to dabble on the boundary of disaster.? - Stirling Moss

Offline steamer

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Re: Finishing off a 5" Gauge Simplex Loco
« Reply #17 on: August 30, 2012, 10:50:57 AM »
Nice work Stew!   Fixing things is often more time consuming than making it!    :NotWorthy:

Glad you got it apart in one piece....that will help!

Dave
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Offline Bearcar1

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Re: Finishing off a 5" Gauge Simplex Loco
« Reply #18 on: August 30, 2012, 04:00:12 PM »
Great going Stew. One has to wonder sometimes why on this Earth, some builders allow such disparity in building something. Perhaps their training using a yardstick was incomplete as a child, or they just did not care. It just seems to me that type of carelessness in achieving accuracy is a sin. (or it should be) You though seem to have it well sorted and I'm looking forward to more of your progress.


BC1
Jim

Offline doubletop

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Re: Finishing off a 5" Gauge Simplex Loco
« Reply #19 on: August 31, 2012, 09:49:54 AM »
Stew

OK I've got to ask. You are now just about replacing/fixing  everything so what about the cross heads and slide bars? The cross heads are an integral part of the valve gear so while you are at it...............?

Pete
?To achieve anything in this game, you must be prepared to dabble on the boundary of disaster.? - Stirling Moss

Offline sbwhart

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Re: Finishing off a 5" Gauge Simplex Loco
« Reply #20 on: August 31, 2012, 01:24:15 PM »
Pete

I've decided that I may as well replace the cross head and fit a piston with cast iron rings instead of the PTFE that are fitted at the moment, I'm going to go the midland show in October so will order the bits from Blackgates to collect at the show.

I've been pondering why he fitted driving crank pins that were effectivly short with one side being shorter than the other that and the fact that the cross head had been mangled to miss the linkage got me thinking that the centre height of the cylinders may be short, the fix would be to pack them, I've made a mental note to check them when I've got the horns machined.

Stew
A little bit of clearance never got in the way

Offline sbwhart

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Re: Finishing off a 5" Gauge Simplex Loco
« Reply #21 on: August 31, 2012, 05:32:00 PM »
Corrected the horn blocks today

As the frame was bolted it stripped down easily if it had been welded I'd have been stuffed.

First job from the drawing identify the datum hole and line the two sides up by putting a tight fitting number drill through the datum hole check all the other holes line up and bolt the frames together with some M4 screws.

Then from the datum hole find the correct position for the centre on the midle horn block and mark it with a centre pop, from this centre pop mark the 7 1/8 position to the other two horn block and mark these.



The frame is to big to machine all three horn blocks in one setting and the job realy needs two vices or to angle plates i've got one of each  :scratch:

So put the vice in the midle of the table and grip the frame with one horn either side of the vice, and starting with the centre horn suport the other side of it with the angle plate when machined index to the other horn and move the angle plate over to support it whilst its machined



To locate the centre of the midle horn use a pointer on the centre pop and zero the DRO



I used a long long series milling cutter, its a regrind that I picked up at a show for no other reson that I may need it some time, nows its time.



Index over with an alowance for the cutter diameter and taking 1mm deep cut nible away the horn, index over the same amount to the other side and mill that side out.



A quik check with slip gauges shows it to be 1.247" that will do me.



Index over 7 1/8" to other horn swap the supporting angle plate over and mill that out the same

To do the remaining horn you have to take the fram out of the vice to reposition it, first clock the cut centre horn verticaly to check its in the vice square.



Then find the edge of this horn.



Index to its centre and zero the DRO then index over 7 1/8" to the remaining horn, machine this the same as the oother two.

this is an overall shot of the complete set up.



A check with slips and a vernier showed that width of each horn to be 1.247" 1.247" and 1.245" and the centre distance to be 7.127"and 7.124"





That will do.

 :D

Stew
A little bit of clearance never got in the way

Offline doubletop

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Re: Finishing off a 5" Gauge Simplex Loco
« Reply #22 on: August 31, 2012, 09:28:30 PM »
Stew

Nice one and good to see that at least the frames were made as a pair, looks like you are at the bottom of the hole and beginning to climb out.

A guy at our club is refurbishing a Phantom (NZ origins) and h describes the frames as being made with a pick-axe and chisel. He's had new laser cut frames made but getting bodged bits to fit was a challenge.

Good to see you are doing the pistons and cross heads. Mine were completely shagged but that was clearly visible when I bought it so that was the first job I knew I had to do. Its better to bite the bullet now and get on with it while the whole thing is in bits or be prepared for a strip down later. I'm learning now that the crossheads and combination lever are an integral part of the valve timing so a rebuild later will mean resetting the valve timing. I'd recommend the Reeves castings as opposed the the Martin Evans fabrication. However, the Smifffy posting on his Royal Scott shows a Martin Evans alternative for more expert builders, if you want a challenge,  http://www.markfsmith.com/.
 
The other consideration is how square the cylinders are in the frames. with the ends of the slide bars held in the motion plate the four parts can become a bit of a wonky parallelogram. I had just purchased a digital angle gauge (I think you've got one) I zeroed it on the stretcher over the eccentric then put it on the Valve chest covers. One was spot on the other about 0.2deg out. I had to shim and trim the slide bars to get them parallel to the piston rods over their length. Only about 25thou bit it was noticeable especially if too tight at one end. If its too loose you be bending the piston rods and wearing the glands. The other consideration with the slide bars is they take all the driving load as max power is at the top and bottom dead centre so the offset loads push against the bars. When the regulator is shut and you've got 6 people on board the pistons are acting like brakes and  all the loads is going through the con rods, crossheads and into the slide bars. It worth getting them right. Get the book "how steam locomotives really work" by Semmens and Goldfinch, an eye opener to what is really going on and how important all these things are.

Pete
?To achieve anything in this game, you must be prepared to dabble on the boundary of disaster.? - Stirling Moss

Offline sbwhart

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Re: Finishing off a 5" Gauge Simplex Loco
« Reply #23 on: September 08, 2012, 09:03:07 AM »
Thanks for your input Pete its good to have a like minded person chipping in. As you said squarness is a big issue as with most engines, and its all to easily over looked, that a great link to the royal Scott build some good info. I think I'm going to make the crossheads myself, I've worked out a method and would like to give it a try, but thats a few months away.

Whilst i'd got the frames stripped thought I'd take the oportunity to tidy up a bit of butchery inflicted on them to line up the boiler blow down valve.



They key hole shape just didn't look like, so cleaned up the hole that was far from round.



Anbd turned up a top hat shaped plug the was a tight fit in the hole, when firmly fixed in placed filed the remaining hole to match, it looks a lot neater now.



I painted the frame parts first with a primer coat then a Hammerite Smooth came out a bit patchy but not too bad as most of the frame will be hidden behind things.



Had one bugger of a job to square up the frames I could get the driving and leading axles horns square but no way would the driving and trailing axles horns square up I tried all sorts of combinations of assembly bending and general jiggery pockery to try and get them square, in the end put it to one side whilst I did something else and godgitated on the problem, this morning I had a brain wave, check out the squareness of the streachers, sure enough the face of the streacher between the driving and trailing axles  is out of square by quite some margine, so that needs making new.

Also found out that Loctite thread loc is a great paintstripper  :Doh:

These are the axles I pulled the wheels off, you can see the fit was bodged by centre punching around it to make the tight fit on the wheel, this and the fact they were under size on the bearings propted me to make new.





So took delivery of some 3/4 mild steel bar,

First operation with a true running collet, centre drill each end and stick a oiling hole down the midle of each end.



Then cross drill 1.5mm into the oil hole this will make oiling the bearings easy.



Then between centres carfully turn down for a nice push tight fit in the wheels, you don't want this fit to tight or you'll split the casting but you don't want it too slack. The advantages of working between centres is that the two wheels will be running true and you can remove it to try the fit and put it back and it will still be true in the lathe.







I was planning to use some cast iron that I had in my stash box for the bearing blocks but when I came to cut it to size the first bit cut great but the second bit was glass hard I cocked up two slitting saws tring to cut it, it must have been chilled when cast it needs anealing, so gave that up as a bad job and order some material from Blackgates.



Just spent the last two days flycutting them to size.



More maching still needed to fit them into the horn blocks and drill to fit the axles, but thats a job for next week.

Stew
A little bit of clearance never got in the way

Offline steamer

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Re: Finishing off a 5" Gauge Simplex Loco
« Reply #24 on: September 08, 2012, 11:05:43 AM »
Glad your doing the job right Stew.....I'm following along.

Dave
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Damned ijjit!

Offline zeeprogrammer

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Re: Finishing off a 5" Gauge Simplex Loco
« Reply #25 on: September 08, 2012, 01:02:34 PM »
Looks like a lot of progress Stew. Looks good!
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Offline doubletop

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Re: Finishing off a 5" Gauge Simplex Loco
« Reply #26 on: September 08, 2012, 10:55:52 PM »
Stew

Nice one I knew you would make sure you'd get it right. I see you've had the same experience as me with the hammerite paint, thining at the sharp edges and loctite is an effective paint stripper. I baked my frames in the barbecue at 200F to assist the curing process, you can just about get the whole thing in a 4 burner barbecue.

Pete
?To achieve anything in this game, you must be prepared to dabble on the boundary of disaster.? - Stirling Moss

Offline sbwhart

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Re: Finishing off a 5" Gauge Simplex Loco
« Reply #27 on: September 16, 2012, 01:31:50 PM »
Thanks for youre interest guys

Little more progress and corrective work this week.

Before I finished off the bearing blocks I was far from happy with the width of the horn blocks, they should all be the same width, but what I had got, was up to 1mm variation even from side to side and up and down on the same horn.

What was needed was to sit them on the front face and flash the back face off to make them all the same. To do this I needed to make a fixture and work out how to clamp the frame too it. For this I used the jig plate that I made some time ago, First clamp a chunk of ally to the jig plate and mill out a platform for the front face of the horns to sit on.



Turn the jig plate round 90 deg then sit the horn on the platform use the jig plate to clamp the frame down, starting with the thinest horn skim it off level, then repeat with the rest to the same zero setting on the mill, and they all ended up the same size and nice and parallel.



I then spent a good day trying to assemble the frame square, (measure across the diagonals to check for squareness) after trying to assemble the frame in all sorts of combination with twisting etc I had a think about what I hadn't checked that may effect squareness, checked the squarness of the streachers, sure enough the front streacher was out of square this was having the effect of pulling everything out so made a new streacher.

Old and new streacher



That sorted it.

With the frame square and the horns all the same it was an easy job to mill the groove in the bearing blocks to fit in the horns, sorry no pic of this

Then it was a matter of drilling out first using centre drill then bigger and bigger drill up to 19mm and finishing off with a 3/4" hand reamer, I marked the blocks up so that I could assemble them in the same orientationas they were drilled.





Drill and tap for the spring hangers and drill the top for an oil hole.



Then final fitting by bell mouthing the groove so that the wheels will move laterly to take up unevenness in the track, what you're after is a nice smooth fit not too tight or the darn thing will derail.



And fitted in the frame



Whilst I was maching I was also painting the frame and letting it dry, toward the end I had to start a new can of paint for some reason it started to look even more patchy than my usual crap painting so gave it another coat even worse  :scratch:

Checked can  :Doh: Dark Green not Black  that will teach me to shop without my glasses.

Stew
 

A little bit of clearance never got in the way

Offline doubletop

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Re: Finishing off a 5" Gauge Simplex Loco
« Reply #28 on: September 17, 2012, 06:56:00 AM »
Stew

That's all looking great. Now just check the cylinders are also square and lined up properly and you are set for getting that sewing machine running nicely. I recall you are already re-doing the motion plates.


Checked can  :Doh: Dark Green not Black  that will teach me to shop without my glasses.
 

........ and re-check the label before applying. Been there done that with cans of black and red, I had been using the black put it down and then picked up the red.

Pete
?To achieve anything in this game, you must be prepared to dabble on the boundary of disaster.? - Stirling Moss

Offline sbwhart

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Re: Finishing off a 5" Gauge Simplex Loco
« Reply #29 on: September 17, 2012, 07:13:57 AM »
Thanks Pete,

Got it noted down to check cylinders, I have a sneaky fealing that they stand out from the frames short and by different amounts, I've decides to compleatly rebuild all the links cross heads and motion plates, that way i will only have myself to blame if it don't work:- but that will be a winter job for know I'm going to get the wheels quartered, and the coupling rods built then its onto the dake build.
A little bit of clearance never got in the way