I Don't Know Why I Ever Got Involved...

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Carrdo
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Re: I Don't Know Why I Ever Got Involved...

Post by Carrdo »

Hi Bill,

I know what you are saying but I couldn't go that route for the reasons I talked about (or didn't dare).

So again, do it the hardest way possible.

The thinking about how something could be done is the most important first step as Richard has pointed out many times so..

After a lot of thought, I came up with the idea of how about using the valve cylinder cover itself as a guide bushing to drill down through the centre of the broken off fastener. I could increase the accuracy of this process by making an additional tiny steel insert drill bushing a light push fit in the cylinder cover clearance hole with the cylinder cover held in place with the other two good screw fasteners. This looked good in theory but the practical problem was due to the very restricted space available, I would have to drill out the centre of the fastener by hand utilizing a tiny pin chuck which I had. To even try to do this, I would start with a very small sharp HSS drill (a #59 drill) sharpened on my fancy Swiss small drill grinder. If I made it through, I would then open out the hole further making another larger drill bushing to guide the larger size drill.

Well, everything looked good (see the included photos) so I started "drilling" except that turning the pin chuck by hand and having only finger pressure to drive the drill forward, it was barely shaving the steel. I must have sharpened the first pilot drill a dozen times, my fingers at the end were raw, lots of navy language as Jack says and I broke the drill more than once. After about 6 sessions of an hour each over three days success! The next size drill used was a #55 drill finally followed by a # 50 drill with each larger drill having its own guide bushing. Once there was a pilot hole opening, enlarging the pilot hole was, relatively, a piece of cake as there was no drill point resistance. With the larger drills, just don't push too hard as the drill wants to grab and it will snap off if driven further without backing off and reducing the pressure.

I left things at the #50 drill size as the tap drill size for this Whitworth thread is a #48 drill which is only a few thousands larger.

Dick Morris,

I know about the alum method and will get into this.

to be continued.
Attachments
41 Maching a Tiny Drill Bushing to Try and Drill Out the Sheared Off Thread.jpg
42 The Drill Bushing in Place on the Valve Cover.jpg
43 The Drill Bushing in Place on the Valve Cover.jpg
44 Hand Drilling Through the Valve Cover Bushing.jpg
Carrdo
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Re: I Don't Know Why I Ever Got Involved...

Post by Carrdo »

"Things were going so well", I thought the rest would be easy. Not so!

I first tried to dissolve the remaining steel by injecting concentrated hydrochloric acid with a syringe needle down through the centre drilled hole as this has been reported to be effective on the net.

Not so as I have reported earlier on another project where a steel fastener was welded into the mud ring on a copper boiler. The hydrochloric acid didn't do a thing and after a week of trying I gave up on this method. Any other strong mineral acid or combination of mineral acids will attack the brass so don't try with them.

Then there is the alum method also reported on the web to be very effective when trying to remove a broken off HSS tap or drill in a brass part ( including many videos of the process).

I have no doubt that the alum method works for small parts where one can immerse the part completely in a pyrex dish containing a saturated boiling water/alum solution and boil the part in this solution for several hours dissolving the steel but not harming the brass. That is the trick but the problem here is I couldn't do that without removing the cylinder which was a no go for me.

So, I thought I could mimic the boiling water process by first injecting the saturated alum solution filling the drilled hole completely with it and then gently heating around the hole with a propane torch to get it to boil. No luck with that either and after dozens of injections and heatings to boiling the hole dry, the remaining steel was as solid and shiny as ever.

After that, I tried several mechanical home made screw extractor tools but again the remaining steel wouldn't budge, it was truly welded in.

What now.

to be continued.
Carrdo
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Re: I Don't Know Why I Ever Got Involved...

Post by Carrdo »

After the last round of failures and frustrations, time to put my thinking cap on again.

I thought, well if the remaining metal is so firmly welded into the brass cylinder casting, why am I waisting my time and effort to try and remove it - why not just re-tap the centre drilled hole one size smaller i.e. with a 2-56 NC tap and have a smaller valve cover fastener. And that is exactly what I did.

I was just careful with the new tap to start it straight and thread carefully so as not to break the tap. That was it - it worked perfectly. I used a commercial socket flat head cap screw this time, trimmed the head diameter slightly to fit the valve cover countersink and put on plenty of anti-seize compound. All of the remaining slotted valve cover Whitworth screws will be remade with the new tap and die set on order as, by now, the drive slots in the remaining fasteners have all but disappeared.

The result is as shown in the first photo. No one will ever know the difference when the valve and cylinder covers are put on but there will be plenty of notes to point this out in the documentation I always make with every locomotive project I have ever worked on.

I have been working on other things like machining a new engine drawbar as seen in the last photo which will replace the hopelessly weak and broken original which came with the locomotive when I acquired it.

How the drawbar is supposed to work as per the Josslin design and how it actually cannot possibly be that way is a whole other adventure which I will be describing.

to be continued.
Attachments
45 The New Socket Flat Head Screw Replacing the Sheared Off Fastener.jpg
46 Some of the Bits and Pieces Used in an Effort to Remove the Sheared Off Fastener.jpg
47 The New Stronger Engine Drawbar Compared to the Original Broken One.jpg
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NP317
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Re: I Don't Know Why I Ever Got Involved...

Post by NP317 »

Another job well done!
RussN
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Greg_Lewis
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Re: I Don't Know Why I Ever Got Involved...

Post by Greg_Lewis »

That deserves some sort of award. The next time I need a root canal, I'll give you a call.
Greg Lewis, Prop.
Eyeball Engineering — Home of the dull toolbit.
Our motto: "That looks about right."
Celebrating 35 years of turning perfectly good metal into bits of useless scrap.
Carrdo
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Re: I Don't Know Why I Ever Got Involved...

Post by Carrdo »

Root canal considerations aside, I also discovered the tender was constructed 3/8" shorter than the Josslin prints call for. Unfortunately, this resulted in the king pin boss in the tender underframe sitting almost directly under the front of the frame of the front 4 wheel tender tuck. This meant that the king pin could neither be installed or removed without first removing the 4 wheel truck. This is not so bad but, in addition, the king pin fouled the truck frame in this location. As the truck needs to both swivel and rock and roll when on the track, I was forced to machine a cutout in the truck frame to give the necessary clearance. See the first three photos.

The last photo shows the new water outlet in the tender floor. This was a straightforward machining operation other than the outlet pipe into which the fitting was screwed into had a 9/32" - 40 ME thread necessitating the purchase of another HSS tap and die this time from the UK.
Attachments
48 Milling a Cutout in the Front Lead Truck Frame to Clear the Tender Drawbar Kin Pin Bolt.jpg
50 The New Tender Drawbar King Pin Bolt Installed.jpg
51 The New Tender Drawbar Kin Pin Bolt.jpg
53 The New Tender Bottom Water Outlet.jpg
Carrdo
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Re: I Don't Know Why I Ever Got Involved...

Post by Carrdo »

Another step forward. This time the boiler firebox grates.

There are 18 bars in total 1/16" thick by 5/16" deep in mild CR steel having 5/32" spacers between each bar. The firebox grates are made in four sections, the two middle sections having 5 bars each and each outer section having 4 bars each. The two outermost bars next to the walls of the firebox were beveled on one side to fit the firebox corners. All of the grate sections are made to fit through the fire door and the entire assembly was made a rattle fit in both directions in the firebox. The grate assembly sits on two end angles bolted to copper extensions on the boiler mud ring.

For a change, everything went very smoothly although there was a lot of final fitting to achieve the correct rattle fit.

The boiler had to be removed from the chassis of the locomotive for the fitting of the firebox grates and this proved to be another adventure but one that was quite successful due to the very clever design of the ashpan and the other fittings which held the boiler in place. Someone had really done a lot of good thinking about how the locomotive could be assembled and broken down into its major components in very tight quarters.
Attachments
54 The Boiler Firebox Grates Ready to be Installed.jpg
55 The Boiler Firebox Grates Installed.jpg
Carrdo
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Re: I Don't Know Why I Ever Got Involved...

Post by Carrdo »

Machining the cylinder and valve covers. This is just a lot of turning work but one has to follow proper methods to achieve good looking and functional parts.

The cylinder and valve covers were all machined from pieces of bar stock with all of the internal machining done first. All of the internal machining was done at one setting to ensure concentricity and the internal cover bores were made a close sliding fit to the OD of the cylinder and valve covers. I did not take any photos here.

Short pieces of surplus round stock were then turned to have a short square step on the end which was a close slide fit in the cover recesses to do all of the external machining also done at one setting. Put on a little Loctite to glue the parts together, let the glue dry and proceed. See the first photo. Just take light cuts with sharp turning tools and don't overdo the Loctite.

After machining, the parts can be separated again with a little heat.

To produce the concave cutouts in the cylinder covers for the valve covers, the boring head and a cylinder cover had to be set central to each other and at the correct cutout radius. I used the quick and dirty methods shown in the second and third photos which is more than adequate for the job. To get the correct cutout depth as the work proceeds, one can remove the cover from the vise and test the cover in place. As long as you don't change any setting, you can then return the cylinder cover to the vise exactly as before.

After struggling to remove all of the old cylinder cover fasteners (which turned out to be 3-48 NC), I replaced them all with new ones.
Attachments
62 Machining the External Side on a Cylinder Cover.jpg
64 Setting the Boring Head for the Cylinder Cover Cutout.jpg
65 Centering a Cylinder Cover in the Vise.jpg
66 Boring the Valve Cover Cutout on a Cylinder Cover.jpg
67 The Cylinder Cover Cutout for the Valve Covers.jpg
68 All New Cylinder Cover Fasteners.jpg
Carrdo
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Re: I Don't Know Why I Ever Got Involved...

Post by Carrdo »

The final result looks pretty good to me.

Next up I will straighten up the lubricator and give it a cover. The lubricator is operated from a separate eccentric located on the front axle of the engine.
Attachments
69 The Finished Cylinder and Valve Covers.jpg
Carrdo
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Re: I Don't Know Why I Ever Got Involved...

Post by Carrdo »

The lubricator chronicles.

The reason why the lubricator was tilted was someone had partially disconnected it from the frame cross member where it was mounted and had removed the eccentric rod from the lubricator swing arm and had also taken out the discharge line which goes from the bottom of the lubricator into the bottom of the smokebox.

Re-attaching the eccentric rod to the lubricator swing arm was straight forward as was putting back the discharge line.

However, fully securing the lubricator body to the frame cross member was a nightmare. It has two mounting hex head screws (the frame cross member is drilled with a clearance hole and the lubricator body is tapped something.

First problem - I couldn't determine what the mounting threads were at all and one mounting screw was missing.

Second problem - the lubricator and surrounds sits down in a "well" under the lead truck bolster plate with the discharge tubing, fittings and the eccentric arm taking up all additional access.

So, one had to pick up and hold a very short fastener with a long arm tweezer and try to maneuver it into position virtually blind. To get any access at all, one faced the old problem of taking virtually everything apart and I was not going to go there. In the end, in desperation, I did remove the lead truck bolster plate destroying several fasteners in the process but fortunately, like the cylinder cover screws, they were 3-48 NC flat head screws which I could replace with new ones.

As a side project, I finally went through all of the loose fasteners in all of the boxes and containers which came with the locomotive. Sorted them into groups so now I sort of know what I have. And out popped the second mounting bolt.

Still virtually no access. By the hand trial and error method, the two fasteners must have disappeared down the "well" at least 40 times over six hours with no results. Frustration in bold letters.

Time to get a lot smarter.

I finally made up two miniature locating pins just slightly undersize to the mounting bolt's OD which, even blind, with a little fiddling, I could push through the holes in the frame cross member and the shell of the lubricator aligning both parts together. With this done, I lightly clamped the lubricator to the frame cross member. Remove one locating pin and again, with tweezers, put in a bolt down into the "well". With the blade end of another tweezer pushing against the the bolt to keep it from falling back out, I was able to get one of my specialized miniature "ignition" wrenches (seen in the photo) on to the hex head (used both ends of the tool) to turn it slightly. Minutely inch the bolt forward until it starts into the thread.

Success, but another pyrrhic victory. I will never touch these screws again.

This locomotive is going to be the death of me.

To be continued.
Attachments
71 Lubricator Swing Arm Attached to Eccentric Rod with Discharge Line into Bottom of Smokebox.jpg
72 Lead Truck Bolster Plate with New Fasteners.jpg
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rudd
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Re: I Don't Know Why I Ever Got Involved...

Post by rudd »

Dick_Morris wrote: Mon Sep 20, 2021 9:48 pm
I've never tried it, but it's claimed that a broken tap or drill stuck in non-ferrous material can be removed with alum. It should also work with a steel screw.
Dick, there is an endorsement for carbon steel taps in what you said. I broke one off in the (of course) last hole to be tapped in a hand pump. It took a few days, but the alum did indeed eat the tap. This does not work on HSS taps, I was just lucky that for that size tap, all I had was carbon steel.
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Bill Shields
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Re: I Don't Know Why I Ever Got Involved...

Post by Bill Shields »

FWIW

Hat off to your patience

been there done that and appreciate what u r going through. I have to look at these designs and wonder about the sanity behind originator.

I have dissolved HSS taps with sulfuric acid..slow going but possible.
Too many things going on to bother listing them.
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