Author Topic: Burrell Single Crank Compound Traction Engines - 4" Scale  (Read 44516 times)

Offline jadge

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Re: Burrell Single Crank Compound Traction Engines - 4" Scale
« Reply #165 on: March 29, 2019, 07:32:28 PM »
I have been somewhat distracted recently dealing with builders, double glazers and kitchen companies in order to get a new kitchen fitted. I've also had to do a lot of painting and sorting out the issues left undone by the workmen. Over two months without a kitchen is tough - there are only so many cans of soup you can eat in a row. However, I did get the locking mechanism fitted to the smokebox door, and the smokeboxes fitted to the boilers before Christmas. Here are the component parts:



Although loosely based on the drawings I have changed quite a lot of the internals to give a proper, symmetric, locking mechanism and I have tried to scale the external parts from pictures of a full size engine. The square hole in one of the locking handles was filed by hand, just for the hell of using old school techniques. The parts fit together nicely and the locking is positive and firm:



Having shown this picture on another forum an error was pointed out. The outer, locking, handle should lock before 6 o'clock, not after, so vibration doesn't loosen it. A bit of quick work with a file sorted that out. I dithered about how to fit the smokebox to the boiler; make a fudge up and that's 1500 quids worth of boiler up the spout. Measurements were made, double and then triple checked. I didn't fancy driling holes through 3/8" steel with a portable drill - too easy to go skew whiff. I needed little incentive to splash out on a mag drill and tube mounting accessory:



The smokebox was aligned by setting an electronic angle meter to zero across the top of the hornplates and then getting the reading to zero again by moving the smokebox assembly with the meter sitting across the top of the chimney base. In order to get to the underside of the smokebox I had to remove a lot of parts at the back and sit the  boiler and smokebox vertical. Quite a lift on ones tod, glad they weren't any heavier. With the boilers vertical it wasn't easy to get the mag drill clamped in the right place while supporting its weight and getting the drill bit lined up with the existing hole. It took sweat, some tears and a lot of swear words. This shows the boilers with smokeboxes fully fitted, plus the front wheel axles:



Just for reference this is a picture taken in the same place, but with the new kitchen installed:



Notice a difference? No engines! The boilers are in the hall, the machined parts and work in progress in the sitting room and the castings in the study.

Andrew

Offline jadge

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Re: Burrell Single Crank Compound Traction Engines - 4" Scale
« Reply #166 on: March 29, 2019, 08:59:09 PM »
Prior to fitting the spokes to the remaining two rear wheels I need to fit the strakes around the rim. The strakes were machined, drilled and countersunk months ago from flat bar. The issue is how to bend them to fit the rim. They need to be curved along the short side, as well as following a helix on the long side. The "normal" ways of using bending rolls or twisting in a vice didn't work for me. In retrospect I could have rolled some flat sheet of the appropriate width and cut the strakes from that on the skew. Although I have been advised that it's a serious amount of work to cut and clean up all the strakes. Given that I l already had flat strakes how to form them? I've seen a Dutch website where they hot pressed the strakes. That seemed like a reasonable way to go, and better yet it's not something I've done before. I started making the press tools by cleaning up some hot rolled steel. That gave me the chance to use one of the slab mills I bought years ago via Fleabay. The slab mill is 4" x 4" running at 88rpm, DOC of 2.5mm, WOC of 32mm and feedrate of 160mm/minute, a bit under 0.1mm chip load, lots of swarf and steam:



It's a UK built mill (Adcock & Shipley) but a US made vice.  :ThumbsUp:

I've still got a lot to learn about driving the horizontal mill hard, and even more about clamping the work. I tried doubling the DOC but the cutter pulled the work out of the vice, and then carried on as if nowt had happened but with a much bigger DOC! The curves on the press tooling were done on the CNC mill using a 10mm ballnose cutter. Initial scallop depth was 0.05mm. Here are the press tools fitted on the flypress:



As expected trying a strake cold simply resulting in the strake springing back with no forming. So I tried one red hot (800░C). That worked well but there were two issues. I'd made the press tool radius a couple of inches smaller than the wheel rim in the hope that the outer edges of the strake would touch first and then the middle of the strake would be pulled down by the rivets. It turned out I needed to decrease the radius by a bit more. Second the scalloping on the press tool marked the work, despite some judicious filing after machining. So I tweaked the CAD model, redid the CAM and also set the scallop depth to 0.01mm. These parameters resulted in a nicely formed strake:



Although not obvious the strake is curved along the short edge, by about 10 thou, as well as having the pronounced helix. The strake is a fair fit on the wheel rim:



And also along the short edge:



The fit is pretty good considering that the wheel rim is less than perfect due to weld distortion.

I'm probably going to run with this, and acknowledge that each strake may require a bit of hand tweaking. I've done some searches, but haven't found anything to indicate how full size strakes were formed. Possibly something similar but with a blacksmith and anvil?

Andrew

Online Dave Otto

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Re: Burrell Single Crank Compound Traction Engines - 4" Scale
« Reply #167 on: March 30, 2019, 12:01:44 AM »
Nice work Andrew and the new kitchen looks great!

Dave

Offline jadge

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Re: Burrell Single Crank Compound Traction Engines - 4" Scale
« Reply #168 on: March 30, 2019, 10:51:43 AM »
Thanks Dave, I try to do nice work, even if I don't always suceed.

I'm pleased with the new kitchen. Even I would admit that the old one was getting very grubby and starting to fall apart. The worst aspect was tiled worktops which, along with the slightly porous finish on the cupboards, was impossible to keep clean. I told the kitchen people that the number one, two and three priorities were easy clean!

Andrew

Offline Kim

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Re: Burrell Single Crank Compound Traction Engines - 4" Scale
« Reply #169 on: March 30, 2019, 04:57:44 PM »
Wow! Those took up most of your kitchen!  Are you going to move them back into the kitchen now that it's finished?
Kim

Offline jadge

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Re: Burrell Single Crank Compound Traction Engines - 4" Scale
« Reply #170 on: March 30, 2019, 08:31:02 PM »
Are you going to move them back into the kitchen now that it's finished?

I'm afraid not, I've been banned from putting them in the kitchen. And if you'd met my mum you'd know it's not worth arguing if you want a quiet life.

Andrew

Online Admiral_dk

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Re: Burrell Single Crank Compound Traction Engines - 4" Scale
« Reply #171 on: March 30, 2019, 08:37:00 PM »
Nice work all the way round Andrew  :cheers:

Offline Jo

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Re: Burrell Single Crank Compound Traction Engines - 4" Scale
« Reply #172 on: March 31, 2019, 09:03:36 AM »
Are you going to move them back into the kitchen now that it's finished?

I'm afraid not, I've been banned from putting them in the kitchen. And if you'd met my mum you'd know it's not worth arguing if you want a quiet life.

Andrew

:lolb:

You are not the worst I know of: ilvaporista's brother Dave had his Bridgeport milling machine in his kitchen  :naughty: and the chips would get everywhere  :LittleDevil: In the end his sister-in-law refused to visit and finally his Mum made him move it out :-\

Jo
Usus est optimum magister

Offline jadge

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Re: Burrell Single Crank Compound Traction Engines - 4" Scale
« Reply #173 on: March 31, 2019, 10:33:36 AM »
Nice work all the way round Andrew  :cheers:

Thank you.

In the round is my next issue. When I fit the strakes I need to predrill one hole per strake. I see two options; one, step round the circumference with dividers, making adjustments until I get back to where I started, as I did when fitting the spokes. Or two, mount the rim on the rotary table and drill each hole using the rotary table to index. I'm leaning towards the latter, as there are 36 strakes and the rim isn't perfectly round, so I suspect using dividers will end with me chasing my own tail.

Andrew

Offline jadge

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Re: Burrell Single Crank Compound Traction Engines - 4" Scale
« Reply #174 on: March 31, 2019, 10:38:53 AM »
had his Bridgeport milling machine in his kitchen

How on earth did he get it in there without a lot of dismantling/

It wouldn't suit me though. For a start I'd need to run a 3-phase extension lead from the garage. And a lot of the tooling is shared with my my other two mills, so I'd be traipsing back and forth like a yo-yo. Not only that I can just lift the dividing head from the shelf to the machine table. No way I'd be carrying it all the way from the garage to the kitchen; or if I did it would be followed by a trip to A&E.

Andrew

Offline Jo

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Re: Burrell Single Crank Compound Traction Engines - 4" Scale
« Reply #175 on: March 31, 2019, 11:22:07 AM »
How on earth did he get it in there without a lot of dismantling/

You only need to rotate the head down and slide off the table  :-X

Quote

It wouldn't suit me though. For a start I'd need to run a 3-phase extension lead from the garage. And a lot of the tooling is shared with my my other two mills, so I'd be traipsing back and forth like a yo-yo. Not only that I can just lift the dividing head from the shelf to the machine table. No way I'd be carrying it all the way from the garage to the kitchen; or if I did it would be followed by a trip to A&E.

Sounds like you have thought about this before  :lolb: I would recommend one of my rollerskates for moving around and lifting tooling on and off the machine beds  :ThumbsUp:

Jo
Usus est optimum magister

Offline jadge

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Re: Burrell Single Crank Compound Traction Engines - 4" Scale
« Reply #176 on: May 09, 2019, 11:01:47 PM »
I've made some more progress on the rear wheels with strakes. I chose to drill the first row of holes for the strakes in the rims using a fudge setup on the rotary table involving some hot rolled steel bar and the right-angle attachment for the Bridgeport:



I decided this would be more accurate, and quicker, than stepping round with dividers. With 36 strakes even a small error in the dividers would accumulate to an unacceptable degree. I'm not a fan of centre drills, but in this application the stub length and hence stiffness combined with the less than perfect surface was useful.

Before forming the strakes for real I altered the arrangement of the fences:



The new arrangement means that there is a closed corner in which to place the red hot strake. This makes it much easier to quickly place the strake before forming. This allowed me to place the strake, form it, turn it round and operate the flypress again before the strake lost its red heat. I managed to drop a couple of red hot strakes; good job my floor is concrete. Fitting each strake required a slight unbending of the helix (adjustable spanner and vice). Once fitted the strake was set to the correct angle and a second hole drilled using the Bridgeport set at a jaunty angle. Lining up was done by hand and no clamping of the rim was needed, it's pretty heavy:



Here is the wheel with all strakes in place. Before taking the picture I checked that the strakes were in the correct sequence. Namely four rivets, one plain hole left, four rivets, one plain hole right and repeat. I discovered that I'd got a couple of strakes in the wrong order. Correction was simply a case of turning the offending strakes around. The drilled holes lined up perfectly; that's the beauty of CNC drilling the holes in the strakes. The plain holes will eventually be opened out for "bolts" to hold the anchors (spuds) for soft ground or for fitting frost spikes:



I'm quite pleased with the fit of the strakes, although might do some final tweaks as I fit and form the rivets:



Before fitting the strakes I spent a duff weather weekend at the gliding club angle grinding the welds on both rims into shape and cleaning up with flap wheels. I did this at the gliding club as I have new neighbours and I didn't think they'd appreciate many hours of noise in what is a quiet rural area. Well at least not until they've got used to the idea of the nut next door with a workshop. I also put a fillet of U-Pol Easy on the welds. I thought I'd been quite economical with the filler, but it still took hours to sand it down. Next job is to experiment on some scrap with rivet length and then close a lot of rivets! I might leave the rivets outstanding once closed as per full size; it being assumed that initial running would wear the rivets down to a smooth fit with the strakes. The second set of strakes have been hot formed, so I can break down the setup on the flypress and set up for riveting. And yes, I did remember to move the fences so that the second set of strakes were formed with the opposite hand to the first set.

Last weekend for the first time I assembled parts into an engine that sits on its own four wheels:



My first reaction is **** me, that's big! And that's without the tender on the back. Good job I moved out of the kitchen; the engine is too wide to go through the door. I had a panic about getting the engine out of the house, but fortunately I specified my newish front door such that it's an inch or two wider than the engine.

Andrew

Offline Kim

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Re: Burrell Single Crank Compound Traction Engines - 4" Scale
« Reply #177 on: May 10, 2019, 12:15:13 AM »
That's IS big!  That's what I've been saying (almost every time I post to your thread! :)).
Nice work on the strakes, they look great!
Kim

Offline crueby

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Re: Burrell Single Crank Compound Traction Engines - 4" Scale
« Reply #178 on: May 10, 2019, 12:27:16 AM »
... I had a panic about getting the engine out of the house....
Had the same thoughts partway through a canoe project... measured the openings about 10 times...

Those wheels are looking great - very well done!   :popcorn:

Offline Jasonb

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Re: Burrell Single Crank Compound Traction Engines - 4" Scale
« Reply #179 on: May 10, 2019, 07:09:55 AM »
Looks good Andrew though you may want to consider flushing up the rivit heads before you roll the other engine onto your laminate floor, I know which material will wear first :-[