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[pettyofficernick]

Alpha is a largish oscillator from Brunel Models, comes as a set of castings and will be the first project for my new lathe. It may seem like a strange choice, but, it is a relatively simple job, and the parts are quite big, easier for my Mr Magoo eyes to see and will get me back into using a lathe, I sold my last one about 20 years ago when, I think, a new washing machine or some other domestic hardware was required.
http://www.brunell.com/popuplargeimage.asp?strImage=121.jpg&strImageType=product&strPageTitle=apostrophemarkALPHAapostrophemark%20TWIN%20MARINE%20ENGINE

[ooyah/2]

Hi Jerry,
 Looking at your post with the bearing blocks set up I ask the question?
 
 How are you going to get the shaft in as the bearings are not split ?
 
 I see from Barry's pic that the main shaft is made up in pieces and bolted to the shaft which will allow the shaft to be assembled in pieces on the base with the solid bearing blocks and hopefully it will all line up, but what happens if you ever require the shaft to come back out?

Perhaps Barry could comment on how he managed to make and fit the main shaft.

I have never been a fan of shafts with the webs bolted and bearings that were not split.

George.

[Jerry C]

Hi George, I'm sure it'll be alright, there's a fair few around by now.  I've no real problems with a built up crankshaft motorcycles have been using them for yonks. I've added a photo of a photo to clarify.  There is a pinch bolt between the main and big end journal holes.  The third, smaller hole is to stress relieve the slot. I suppose it comes out easier than it goes in.
Jerry.

[frazer heslop]

Same idea as the Duval wobbler 

[BarryM]

Hi Jerry,
 Looking at your post with the bearing blocks set up I ask the question?
 
 How are you going to get the shaft in as the bearings are not split ?
 
 I see from Barry's pic that the main shaft is made up in pieces and bolted to the shaft which will allow the shaft to be assembled in pieces on the base with the solid bearing blocks and hopefully it will all line up, but what happens if you ever require the shaft to come back out?

Perhaps Barry could comment on how he managed to make and fit the main shaft.

I have never been a fan of shafts with the webs bolted and bearings that were not split.

George.

George,
All the pins forming the crankshaft are secured in the webs by the clamping screws running through the latter. It's a case of building it up section by section between the main bearings and checking the alignment and offset as you go. (This is accompanied by many words which cannot be repeated on the Forum as sections slip out of alignment - frequently.) Not easy and a third set of fingers would be useful but it works in the end.
Barry

[ooyah/2]

George,
All the pins forming the crankshaft are secured in the webs by the clamping screws running through the latter. It's a case of building it up section by section between the main bearings and checking the alignment and offset as you go. (This is accompanied by many words which cannot be repeated on the Forum as sections slip out of alignment - frequently.) Not easy and a third set of fingers would be useful but it works in the end.
Barry

Hi Barry,
Just as I thought, I think that it,s a bad design to make the shaft as the drawing and it must be a real pest to get them all in line.
Please don't think that I am down crying BOG'S design as I do like it very much but every thing can be improved on hindsight.
 
I shall stick with fabricating my crankshafts by glueing withn Loctite 603 and then taper pin the joints.
All as per the pics of a Stuart Launch engine recently completed, also the bearings changed as I think that the method employed by Stuart in that they use the base plate as the bottom half of thebearings which mean you must have a very long reamer to ream the 3- blocks in situe. I have made the bottom half and top half together as per full size practise and very much easier if the shaft ever has to be removed.
 
George.

[southsteyne2]

I agree with George with no disrespect to the original design, unfortunately  this design does not allow for wear, split bearings can be reamed an exact fit and shimmed to allow for running in as wear will take place after a few runs,I would also make large oil cups to prevent dirt ingress
Cheers
John

[BarryM]

I deviated from Bog's design by press-fitting bronze bearing bushes in the main bearings and reaming through the lot in situ. I also installed oil cups as I thought the original idea of simple holes in the bearings would be messy in practice.

As I am sure Bog would be the first to acknowledge, his design of an "engine from scrap" made up as he went along, was just a starting point. There's nothing to stop anybody applying their own tweaks as they think fit.
Cheers,
Barry M

[Jerry C]

Please keep all mods coming, surely they are food for thought and other builders can incorporate them in their builds. However I intend to carry on building the engine as it is. On the subject of future wear I don't envisage any major problems.  I run my present plant 2hours per week max.  I think this engine will outlast me and anyway I'm building two at the same time so it should last twice as long. Of course if they don't work then they'll last forever.  Had a great day at the lake today with S L Wear which performed faultlessly.
Jerry.

[ooyah/2]

Please keep all mods coming, surely they are food for thought and other builders can incorporate them in their builds. However I intend to carry on building the engine as it is. On the subject of future wear I don't envisage any major problems.  I run my present plant 2hours per week max.  I think this engine will outlast me and anyway I'm building two at the same time so it should last twice as long. Of course if they don't work then they'll last forever.  Had a great day at the lake today with S L Wear which performed faultlessly.
Jerry.

Jerry,
I was never concerned about bearing wear, these little engines with small dia shafts can run for ever,  more about how to assemble the shaft and get everything to line up without the bearings being split.

Barry in his post confirmed that it is a bit of a trial getting them all to line up with the use of many expletives and much frustration and the need for another hand.

So you have that to look forward to x 2, best of luck.

George.

[Jerry C]

Today and yesterday oi 'ave mostly been finishing off the base plates. I cut out the clearance holes for the crank webs. I used a 1/8" mill  in the chuck and the plates in the milling attachment.  Again I had to slide the piece in the jaws because of the limited throw of the milling slides. I tidied up the cuts with a file before bolting both plates together and again with the pieces in the vice I used the file to make them both the same. After de burring all the edges I moved on to turning a piece of 6mm round stainless steel to 5mm for all the shafts. I did a test to check that the rotating centre was concentric with the three jaw chuck.  I made a couple of passes with the tool over a 65mm length, then checked the diameters at the ends and middle of the cut. The ends were 7thou different with the middle 3 1/2 thou. Slacked off the adjustment Allen screw on the tailstock and moved it a fraction then locked it off. Another couple of cuts and re measured and only 1 thou out over 65 mm. Near enough for me. Turned a new piece down to 1 thou less than 5 mm then polished the piece linisher tape while spinning it in the lathe. Checked that all bearing blocks fitted on shaft without binding. They all feel Perfick to me.  I put the 4 bearing blocks on the shaft and dressed the bases on the dressing plate until all the same and all tool marks removed. Repeated the process on tops and sides. Used the plate to make sure both base plates also flat.  Loosely attached the bearing blocks by numbers to corresponding base plate, slid shaft through bearings and tightened the screws. Shaft turns and slides freely with no play. Just enough clearance for oil. Result!! I'll make all the shaft pieces tomorrow. Then I'll have to go bumming again for stock for the crank webs.  I've got a suitable piece for the flywheel.
     I apologise for mixing up mm and thou but I can't think in metric.
Jerry.

[SailorGreg]

Good job Jerry! I can feel your satisfaction from here, and well deserved.   

Don't worry about the metric and imperial, I also use a mixture when measuring things. I tend to use inches for "big" measurements with a tape and metric for "small" ones with a vernier or six inch ruler.  Sorry, 150 mm ruler.   

Greg

[Jerry C]

Today I finished all the shafts for the crankshafts. Just a case of feeding the stock through the chuck turning to 5mm, removing the tool marks with linisher tape, de burring and parting off to length. 
       I went up to the lake to my friendly factory man for some 28mm brass for the crank webs but alas no joy, only stainless steel, so got two pieces 28.6 mm diameter and some brass to make the cross heads out of. Returned to workshop, sharpened tools, and started cutting web blanks.  It machines OK but, when it came time to part one off, my parting tool wouldn't look at it. Used a round nose tool to make a guide cut and with piece rotating, cut them off with big hacksaw. Easier than I thought it would be. Made four before dinner.  Will do some more tomorrow but got to go for a 42 mile bike ride in the afternoon.
Jerry.

[Jerry C]

Finished the web discs and started on the drilling. Similar M.O. As for drilling the base plates.  Shipped the milling attachment and the Jacobs chuck. Put a disc in the milling vice Central and backed it up with a parallel. I found the vertical centre of the disc and locked the vertical slide. Found the horizontal centre and zeroed the wheel. Backed the slide out a little then approached the centre again.  All positions approached from out side to eliminate backlash problems. Centre drilled then drilled through with 4.7mm stub drill followed by 5mm reamer.  Wound the slide out the required distance (0.315"), overshot a little then came back to the mark. Centre drilled followed by 2.5mm drill. Returned slide to zero then moved slide in 0.393" and drilled 3.7mm hole followed by 4mm reamer.  Put a stop on the vise abutting the piece then removed piece and loaded the next one against the stop.  Repeated the process 3 times, deburred and put them in the bearings on the shafts with big end shafts fitted and they turn freely.  More satisfaction, oh yes. 
Jerry. 

[southsteyne2]

Looking good Jerry ,my choice would have been a four jaw chuck and drill all before cutting off to size how will you secure these disks to the shafts?
Cheers
John

[Jerry C]

John, the man says that if you drill first then cut, if the drill wanders the whole thing doesn't work. He says to use a jig and drill on drill press. Mine shakes about a lot and so I steer clear of it whenever there is an alternative. As to securing webs to shafts, after shaping (in bulk) individual webs are cut with a slot drill through the centre of each 4 and 5mm hole just breaking through into the 2.5mm crack stopping hole. A hole is drilled across the cut, between the 4 and 5 mm holes, threaded on one side, with a cap headed screw inserted to pinch the webs onto the shafts. It's easier with a picture but I don't want to keep copying bogstandard's instructions. I've printed them off from paddle ducks site and until I know better am sticking to what he says. I'm working with a Taig outfit and prefer to use the graduated(imperial) wheels to navigate(parallel and meridian sailing) around the cutting/drilling plan, rather than marking out and drilling marked holes.
Thanks for watching.
Jerry.

[Jerry C]

On Thursday I started shaping the crank webs on the milling attachment. I ganged them all together with 5 & 4 mm rods in place and 0.5 mm shims under the 4 mm rod ends to ensure cuts are parallel to the hole centers and clamped it all up, leaving rods and shims in place for strength. Applying cutting fluid liberally with a brush I started cutting. What a horrible job!!  Noisy, smelly and messy. This stainless steel turned beautifully but milling is a different ball game. Doesn't mill easily. Shrapnel flying everywhere, mostly in my direction. Best I could manage were 10 thou cuts. My largest cutter is a 1/4" triple fluted. It's sharp but made heavy weather of it. It took 4 hours to do the first side. The final finish however was exceptionally good. Turned the pieces round and carried on this morning after a cup of tea in the garden watching a large flock of swallows flitting around having their breakfast. One even took a fly off my head. Today went better or maybe I'd gone a bit deaf from yesterday. Finished off in three hours. At the end I was getting very envious of you guys with Myfords and bigger.  Deburred and set the first web in the milling vice using the same rod and shim set up to get pinch bolt hole square across the web.  Center drilled then drilled across the web leaving a blind hole for aesthetic reasons. Used the correct tapping drill for 8 BA then drilled half way through with a number drill (can't remember which one for the clearance hole then tapped the hole. All went well until the third web when I broke the end of the taper tap. Disaster! Thoughts of driving to Newtown on Monday for removal by spark erosion or worse still making another web! What to do. I drilled through from the other side until the drill met the bit of tap and as expected broke off at the shank. Pulled the broken piece of drill out then with the piece on the anvil on the bench vice drove the shank through the hole and knocked the tap part straight out the way it went in. My luck's still running!  Never did like blind holes anyway. So I saved the piece. Carried on using another number drill a fraction bigger than the tapping drill and no more blind holes.  Went ok from then on.
Finally cut the slits with the slitting saw using the same lay out but this time removing the rods prior to cutting. 
Assembled both crankshafts using temporary screws. Final assembly will use Allen head set screws in counter bores.  The shafts are only a little tight but will bed them in with an electric drill.  The man says to use T cut or Brasso to bed in but I'm not happy introducing abrasives into the bearings so will run in on kerosine. So I'm a tied but happy little bunny.
No more work on the engines for a bit cos I've got to polish 100 EPNS table forks and bend the tines to make place card holders for daughters wedding in a fortnight.  Probably a few other jobs to do as well. 
Jerry.

[pettyofficernick]

Excellent work Jerry, keep going....

[SailorGreg]

    Lovely recovery Jerry.

With your daughter's wedding coming up I'm surprised you can find the time or money  to do any engine building at all!  And the bike ride??!

Good luck with the cycling, the wedding and finding time to do a little engineering.  Looking forward to the next episode.

Greg

[Jerry C]

Thanks guys. I was mortified when I broke the tap. I broke three 1/4" Whitworth taps when cleaning out crankcase threads on triumph engines in another life. I used to take them to a firm in Newtown and they removed them using spark erosion. Used to take a couple of hours but he was a vintage bike geek and never ever charged me. I stopped doing them and drilled through then heli coiled them all.  The guy that owned Re-coil gave me unlimited sets of everything I needed. Never had an oil leak. Am in serious training for the Tour de Môn Canol in August. 76 miles but compared to Etape Eryri the hills are a doddle. Famous last words. Thanks for the encouragement.
Jerry.

[pettyofficernick]

My dad worked for a company called Metalock, and he used to break a lot of taps, as some jobs had thousands of tapped holes. He used a little device that had 3 prongs that slid into the flutes on the broken tap, enabling them to be unscrewed. The actual pieces of machinery he would be repairing being far too big to take somewhere for spark erosion......

[Jerry C]

They probably weren't 8BA taps. I've seen the metaloc process used at sea. Drill a hole, tap it and screw in a brass plug. Drill another interlocking hole and repeat the process the full length of the crack finished off with molten lead? Simple but saves a fortune in castings.
Jerry.

[pettyofficernick]

The material that went across the fracture was mild steel, and the studs were HT steel, no hex head but a little tab that fitted into a socket driven by an air wrench, I used to spend the school holidays at work with the old man the last couple of years at school and became quite adept at it....

[Jerry C]

I believe there was another crack solution. A bit like the old repairs to cracked china. They drill holes  either side of the crack a set distance apart. Join adjacent holes with a slot then drive in a red hot dumbbell sectioned staple slightly shorter than the hole centres.  When they cool they shrink and pull the crack together. 
Jerry.

[pettyofficernick]

I don't recall them being red hot, one of my jobs when helping Father was to go and find a gas axe and anneal bundles fo the dumbell shaped material (Metalock keys) these would be driven into the slot with an air powered peening tool, if the slot was deep enough for 4 pieces, after annealing 5 would be rammed into the slot and ground flush. Sorry Jerry, I am diverting from your thread, I could start a thread on the subject if anyone is interested, I have a book full of photos somewhere.....