Drawing 904

Hornplates

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Thursday 28th July 2011

Started on the crankshaft and second shaft bearings. Cut the stick of bearings up and skimmed them in the mill.

Soft soldered them together. Not sure about this soft soldering stuff, and especially what to do with the flux. Applying the flux and then heating the bearing didn't seem to be the right thing to do - it just seemed to burn off and leave a residue which made soldering totaly impossible.

I ended up applying the solder to the un-fluxed surface and then pushing the resultant solder blob around with a small paintbrush dipped in the flux. Seemed to do the job! I then added some more solder and mated the two halves together.

Monday 15th August 2011

Made up a plug gauge for the bearing bores, 7/8" dead on, and -1 & -2 thou. I'm crap at measuring bores so I figured this would be the easiest way.

Wednesday 17th August 2011

Set up a bearing in the 4-jaw and made sure that the split line was exactly on the lathe centre. Faced off the end and bored the hole up the middle.

Thursday 18th August 2011

More boring of the other bearings.

Friday 19th August 2011

Went to the Bristol Model Engineering Show, and bought a 5C collet chuck for the Boxford. Spent an hour or so turning a backplate to suit. Shrank the chuck onto the backplate by heating the chuck gently in the oven (and got caught doing it!) and cooling the backplate in the fridge.

Saturday 20th August 2011

Made a mandrel to hold the bearings for machining the outer diameters.

Bearing Mandrel

Sunday 21st August 2011

Machined the outside diameters of the bearings.

Machining the OD Machined OD

When taking the last rectangular bearing from the mandrel I thought it seemed kind of odd, then it fell into two pieces in my hands... So much for my soldering! The other three seem OK though.

Monday 22nd August 2011

Made a split steel ring so that the bearings can be held on the OD to allow the bearings to be machined to length. The benefit of this plan really showed itself when the bearing dropped in two...

Machined the end cheeks of the rectangular bearings to size, using the mandrel in a 5C square fixture - makes machining square things easy! Had to use a Jubilee clip and the split ring to hold the failed solder joint bearing together.

Once again, had to make sure that the split line is horizontal.

Holding the failed bearing together Setting the bearing level

Tuesday 23rd August 2011

Machined the bearings to length, after grinding a tool to make the radius on the rectangular bearings.

Finished bearing

Tuesday 26th August 2011

Need the bearing caps so that the bearing housings can be machined, so made them next. Got the power hacksaw hacking off 4 blanks from a bit of 1/2" x 1-1/2" steel. Clamped flat in the vice and machined the shoulders at each end of each of the blanks, and took the blanks to thickness.

Set the boring head to the correct diameter. Clocked the spindle to the fixed jaw of the vice, then moved it the correct radius away and set the boring head so that the tool just touches the fixed jaw.

Wednesday 27th August 2011

Clamped the blanks to an angle plate and clocked off the shoulders, zeroing the DRO at the finished depth of the bored bearing recess. Bored the bearing seat on one each of the two sizes of bearing cap. Realised at this point that I only needed three of the bearing caps - the fourth is a casting. I also noticed that the bearing caps have bowed - this is because metal was only removed from one side of the blank. I knew this would happen, but for some reason it didn't occur to me. Annoyed.

Boring the bearing cap

Tuesday 6th September 2011

Started on the nearside crankshaft / 2nd shaft bearing housing. Noticed that the casting seemed to be slightly bent so I couldn't grip it like the book recommended. Instead I gripped it flat in the machine vice and took a skim off the face which bolts up against the hornplate. Because the machining is only on one side I figured that the casting might relax some more so at that point I took it out of the vice and left it for a week or so.

Wednesday 14th September 2011

Put it back in the vice and took the finish cut. Using some insert milling cutters bought from CTC Tools in Hong Kong. Fantastic...

Monday 19th September 2011

Clamped the casting onto parallels on the milling machine table. At this point I noticed that the casting has indeed relaxed, by 10 thou in the middle of the casting relative to either end. Bugger. Not sure how to carry on with this one. I have to face the other side of the bearing housing to be parallel to the first, so I did that.

Second operation on the bearing housing

Monday 26th September 2011

Decided to complete the bearing housing as is. If the shafts bind, I'll just have to make another one. So I bored the two bearing seats, and milled the slots to match.

I then made a drawing of the casting so that the rivet holes are all dimensioned from a single datum, and not all relative to one another and to the casting edge. I decided to take one of the shaft holes as a datum. Unfortunately this didn't work out as intended, and I ended up centre drilling 6 of the holes in the wrong places. Took me about an hour to work out what I'd done wrong. I'll have to fill the holes and hope they don't show once it's painted.

I have to say that this part is very badly dimensioned. Referencing off a cast edge can't be good practice! All the information is there, between the nearside and offside housings, but there is a considerable amount of working out necessary to allow sensible datums to be used...

Fitted the bearings and their caps into the casting. Easier than I expected it to be...

Tuesday 27th September 2011

Took a skim off the offside crank / 2nd shaft housing so that it can sit and de-stress. Hopefully that'll allow the finishing cuts to remove any warp which develops. It already looks visibly quavered, slightly...

This is the worst casting I've had so far (the rest so far have been perfect!) - it has lots of blow holes, and a chilled bit on one edge. Good job I was using the tipped tooling - it complained a bit, but did the job!

Made the studs for the bearing caps. Bloody hell - what a pain. Need to find a better way of doing that - there'll be plenty more to make. The pain included snapping off an embryo stud in the die. Took some time to remove the offending article...

Tuesday 13th December 2011

Continued the machining of the offside crank / 2nd shaft housing.

Wednesday 14th December 2011

Finiahed the machining of the offside crank / 2nd shaft housing.

Saturday 7th January 2012

Start of machining the hornplates

Started on the hornplates. Marked out on the inside of the offside plate. Bolted the plate to an angle plate and used a height gauge first in one axis and then in the other.

The dimensions for the square of dummy rivets are pants. Had to deduce most of them - drew them on Rhino to make sure they looked right. Drawing with dimensions here (right click & choose "Save Link As").

Once the dimensions looked right, clamped the two plates together using three toolmakers clamps and clamped the whole lot into the mill table. Set the plates parallel and square and used the DRO to index the holes, using the marking out to check that I didn't mess up along the way. Thank God for 4 facet ground drills - using one I didn't need to spot drill the holes first. Halved the time taken...

Monday 9th January 2012

Deburred all the holes in the hornplates. There are a lot of 'em...

Drilled and tapped the holes for the bearing caps in the offside crank / 2nd shaft bearing housing. This meant that I could make the stub mandrel and turn the large diameters which locate with the hornplates. (Makes sense to do both bearing housings at once.)

Machining the locating boss. Machining impinging on the boss

Despite what the book says, it isn't possible to hold the housings onto the mandrel using the bearing caps. If you try, you'll end up machining a goodly portion of them clean away. Fortunately I noticed this before I norsed up the bearing cap, and made up a sacrificial cap from a bit of MS flat. Turns out the bolts holding it down are sacrificial too... (Picture left).

The casting also gets a bit of a bashing (picture right)- if I were machining the casting again I would centre it on the edges of the larger boss rather than the bulk of the boss itself. That way, the bit of the casting which gets slight "touched" during the turning operation would be symmetrical. Mine isn't, quite. It'll need some fettling later...


Tuesday 10th January 2012

Machined the locating bosses on the nearside crank / 2nd shaft bearing housing. Much easier than the offside, but I was a bit miffed to find that I didn't end up with a full "disc" - there is a small flat at the bottom of both bosses. Not sure what I could have done differently to avoid this...

Fitted both bearing housings to their respective hornplates. Rather pleased with the fit obtained actually! :-)

Spotting through the rivet holes in the bearing housings allowed the remaining holes to be marked on the hornplates for the spectacle plates. The nearside holes for the front spectacle plate were spotted through from the offside plate 'cause there isn't any hornplate under the corresponding holes on the nearside bearing housing. If you see what I mean...

Not sure I've done anything wrong - everything seems to be to drawing, but the topmost holes for the front spectacle plate are very close indeed to the bottom of the bearing housing casting. If the two holes were marked as "countersunk" then I could understand it, but they aren't. Have to research this a bit, but it's a bit late for my hornplates. The holes are drilled...

Also marked and drilled the mounting holes for the water pump. The top left hole (looking at the drawing) is bloody close to the edge of the hornplate, but once again it's to drawing.

Wednesday 11th January 2012

Made up three 7" rods to space the hornplates apart. Having trial assembled them I took the assembly into the kitchen and compared it to the boiler. Should have looked at the boiler sooner - the middle "zig-zagged" column of hollow stays are wrong. It turns out that the drawings are wrong... Probably as a result of the boiler being drawn with the engine facing left and the hornplates drawn with the engine facing to the right. Bugger.

Oh, and having looked at some pictures of full sized Fowlers it seems that the 7/16" dimension on the bearing housings from the bottom row of holes to the bottom of the casting is a bit generous. Which is why the top rivet for the front spectacle plate clashes with the bottom of the bearing housing. Solution is to file away the bottom of the casting.

Saturday 14th January 2012

Took a skim off the hornplate surface of the 3rd shaft / axle bearing housings. They will now sit for 4-6 weeks to see if they warp with the released stress.

Sunday 15th January 2012

Made the first part of the 2nd shaft offside bearing cap. I've decided to make this in three pieces and silver solder them together, although I'm so crap at silver soldering that I've no idea if I can make it work... I also have little or no idea how to hold the bits together during the soldering. Time will tell!

Monday 16th January 2012

Went out in the garage for an hour or so (it's F cold out there!) and achieved pretty much nothing.

Tuesday 17th January 2012

Milled the radius on the offside 2nd shaft bearing cap.

Also tried to harden a bit of silver steel. Unsuccessfully. Arse.

Sunday 29th January 2012

Some progress since the last update...

Tried silver soldering some steel to make an oil box for the crank / 2nd shaft bearing cap. And it worked! Turns out that having the right "pickle" (10% H2SO4) and using MAPP gas makes everything OK...

Subsequently I (more carefully) made 3 off oil boxes. Used propane on its own for the second and third - seems to be sufficient for something this size. Cheaper than MAPP...

Still need to drill the boxes for the "hinge" - in doing so I've already broken 2 x 1mm drills. I am NOT enjoying this task...

Oh, and the "silver steel" which I entirely failed to harden turns out to be exactly that. NOT silver steel. I tried to harden a different bit of SS and it worked just fine. So thanks to whichever show stall sold me that length of stuff... Lesson learned. If you want to be sure of the type of steel you're buying, get it from somewhere reputable.

I've also made the other 4 studs for the bearing caps. I HATE making studs.

Monday 20th February 2012

Since the last update I've drilled the 1mm holes for the oilbox hinges, fortunately with no further drill breakages. Also, the box with the bits of drill still in it has had the offending side removed and replaced.

Today I fitted the lid to the first box. Quite please with the result actually!

3rd Shaft / hind axle bearing housing. 3rd Shaft / hind axle bearing housing.

Started on the 3rd shaft / rear axle bearing housing. Hopefully it's had time to bend if it was going to. It hasn't.

Clamped the housing on 1-2-3 blocks on the previously machined surface (left) and took a skim off the top surface of the mounting hole bosses and rib. I aligned the housing roughly by its edges - I think there's enough meat on the bosses to allow them to be machined fully. Time will tell!

Then flipped it over and clamped on the newly machined surface (right), and machined the back surface to thickness. Clamps (three pairs rather than the two shown so that there would be two pairs on and one off when boring the outside of the bosses) had to be removed and replaced several times during this operation.

Machined the surface of hind axle boss. Machining cast iron is 'orrible...


Tuesday 21st February 2012

Machined the surface of the 3rd shaft boss using the setup above.

Fitted the lid to the second oil box. Not quite as nice as the first, but it'll certainly do.

Friday 24th February 2012

Bored the 3rd shaft and hind axle holes. Awful chattering on the 3rd shaft hole. While boring the hind axle hole I noticed that if I increased the feed rate dramatically the chattering virtually went away. A fine finishing cut using the spindle feed left quite a good finish.

Turned the boring bar around and machined the outer surface of the hind axle boss. Had to remove the right hand most clamps to avoid the boring bar hitting it. Bizarrely there was no chatter at all, but it was done at the same speed as the holes and is of course a much larger diameter meaning that the surface speed is much higher. The mill rattles a bit when run in reverse though...

Saturday 25th February 2012

Machined the outer surface of the 3rd shaft boss. Bloody hell - what a kerfuffle... Using the extension bar on the boring head, the head wouldn't move "right" enough to get to the final diameter (the mill is running in reverse, remember). So take the extension piece out and put the boring bar directly into the head. Now it won't move "left" far enough to meet the surface already machined. So swap to a different (smaller diameter) boring bar. Reset the feed depth knock-off and have at it again. Then swap to yet a different boring bar - one with a bit of toolsteel sticking out of it, ground to a nice rad. This bar will only just get to the outer surface of the boss... And it chatters. Apart from that - it's great.

Cast iron is awful stuff to machine. My hands won't be clean for weeks, and all I can smell is "metal".

Sunday 26th February 2012

Machined the other side of the 3rd shaft / hind axle bearing housing, including the surfaces for the stays. And the mounting holes. By the way - the stoopid radially dimensioned pair of holes at the bottom of the casting turn out to be 1.29" below the next set of holes.

I have to say - for some reason I haven't enjoyed machining this casting at all. Not looking forward to doing the other one.

Still have to machine the oil box at the top of the casting, but apart from that I think it's done. Oh, and the oilways. And the dummy stud holes at the bottom. And the holes for the stays. But apart from that...

Monday 5th March 2012

Finally got around to drilling the correct holes in the hornplates for the dummy stay rivets, and blocking the wrong ones up. Did this by very slightly counterboring both sides of the holes 7/32" and whacking in a 6mm length of 3/16" rivet. Added a bit of Loctite - can't hurt... Laid the hornplate on a thin washer for the first few whacks so that there was still some rivet sticking out of the opposite side. Ground off the excess with the angle grinder. Job done! Another excellent suggestion from the good folks at Traction Talk Forum

Monday 5th May 2014

Started the second 3rd shaft / hind axle bearing housing. Skimmed the "front" side of the casting before flipping it over and skimming the back to thickness.

Tuesday 6th May 2014

Milled the back of the two bosses to length. Crikey - there was a lot of metal to remove from the 3rd shaft boss for the nearside casting!

Tuesday 6th May 2014

I. Hate. Boring.

Started boring the axle bearing bore. Can't stop the damned boring bar chattering. I've tried lower spindle speeds, higher spindle feeds, lower feed rates, higher feed rates, lower cut depth, bigger cut depth, HSS tool, carbide tool, insert tool. Nothing makes any difference. If anyone has any dynamite tips, please let me know, and put me out of my boring misery.

Tuesday 13th May 2014

Finished boring the axle hole.

Thursday 15th May 2014

Swapped the setup to bore the outside of the axle boss.

Saturday 17th May 2014

Finished off the outside of the axle boss. Moved the setup to bore the outside of the 3rd shaft boss.

Swapped the setup back to inside boring for the 3rd shaft hole. Suffered a massive brain fart and managed to bore the hole over 1/8" too big. My mind was firmly in "outside diameter" boring mode so merrily bored right past the correct diameter. The penny only dropped when the telescopic bore gauge which measures to a max of 1-1/4" didn't touch the sides...

Sunday 18th May 2014

Finished off the 3rd shaft / axle bearing housing. Phew. Glad that's done...

Sunday 8th May 2016

Turned the first axle bearing. Rather therapeutic after loads of spoke bending & riveting.

First hind axle bearing

Monday 9th May 2016

Turned the second axle bearing. Buggered this one up - it's a running fit in the bearing housing instead of a shrink / press fit. Arse. Tomorrow I'll measure it properly to see if Loctite will take up the slack, otherwise I'll try to knurl it. Failing that, it's a new casting. Bum.

Saturday 14th May 2016

Before fitting the axle bearings, checked what was still to do on the housings. Turns out, quite a lot!

Firstly, on the first 3rd shaft / axle I forgot to machine the underside of the axle stay "tab". Reading some other build diaries, it seems that some much needed room on the backhead is made if this stay is bolted to the bottom of this tab rather than the top. One the second one I machined I forgot to machine both sides.

Did the second housing first. Machined a plug to be a snug fit in the 3rd shaft bearing hole with a hole to bolt it to the mill table. Centred the mill on this boss once it was bolted to the mill, then centred on the axle hole with the housing loosely clamped to some 1-2-3 blocks.

Axle stay flange machining

The other housing was clocked in to the already machined surface on the stay flange.

The other thing to do was machine the oil box on the top. Just enough headroom in the mill to do it. The setup is slightly wobbly at the top, but I couldn't think of a better way.

Oil box machining

Also realised that the top surface of the casting should probably be machined so I did that at the same time. Drilled the two 2BA holes, and the oil tube hole in the bottom of the oil box.

3rd shaft / axle bearing housing oil box

Monday 30th May 2016

Over the past few days I've been pottering a few minutes a day. Finished the second oil box.

Noticed whilst doing the second one that it looked noticeably shorter than the first one. Harumph - don't know why, but I somehow misread the height of the oilbox as 3/4". So it has to go back on the setup. And because it's having to be made shorter, of course now it's not deep enough. Double harumph.

Drilled the oil pipe holes in the axle bearing boss. Did the angled one using my tilting angle plate. Got distracted after that trying to make the angle plate operate more smoothly - discovered a "hump" in one of the sliding surfaces. Filed it off. Better. Until I assembled it and discovered that a large part of the lumpy nature of the sliding action is due to the clamp plates which appear to be bits of flat bar bent by tightening the pinch bolts... At some point I'll make something better.

Finished off a little experiment - turns out that a copper washer Loctited to a copper rod can be milled without the washer flying off. This means that I have a viable alternative to soft soldering washers on the boiler to make the over-length hollow stays. I'll stamp a number on each once they're the right length so that if they ever come off they can be stuck back on in the right place. The only reason that might be a problem is if the hornplates have to be removed after the engine has been run and the heat has caused the Loctite to come unstuck.

Tuesday 28th June 2016

A bit of progress since the last update.

Pressed in (one side) and Loctited in (the other) the hind axle bearings.

Turned up 24 copper spacers about 5mm thick to Loctite onto the boiler to create over-length hollow stays.

Plugged the through drilled oil holes for the hind axle bearings.

Turned a sleeve to correct my cock-up with boring one of the third shaft bearing housings. Pressed it in.

Turned one of the third shaft bearings completely, and the other just needs the flange facing to thickness.

Sunday 8th July 2016

Some more progress. Finished the 3rd shaft bearings and pressed them in.

Drilled out the oil holes in the 3rd shaft bearings.