There must be a better way!!!

In process of making a mess of a Tiny Power V twin.

One (of a number of) failure was the eccentrics. Totally 'Horlicksed' the castings, so decided to make a new pair from scratch. Chopped a 2" chunk off a 1.75" bar and generated a thickish cruciform shape on the D-W. Into the four jaw and reduce the required length (approx .75" ) to slight oversize round. Onto motorised hacksaw and saw the bearing clamp separation, leaving the remainder solid. Onto drill and eyeball the holes for the clamp bolts (6BA) ... close enough for Government work and good enough for me. Insert bolts and tighten and back to hacksaw and slice off the two required widths. That's it, so far. Tomorrow will put it back in the 4 jaw and drill and bore to final size and groove for the eccentric axial locator.

All this makes my few remaining brain cells hurt and I'm sure that there must be a much simpler method. Since I'm likely to 'Horlicks' this pair as well, any suggestions for a better way for the next attempt, please?

Rgds
Bill

Edited By Cornish Jack on 26/11/2012 17:46:59

Edited By Cornish Jack on 26/11/2012 17:47:23

Sounds more or less how I would go about making eccentric straps from barstock Bill, except I don't know what "Horlicksed" means.

What exactly happened to the first ones? Bore too big? was the groove a problem? Did the straps break loose out of the 4 jaw during boring?

I would make a couple of rough bore gauge plugs first, one to sneak up on the bore size by frequent test fitting while boring the straps, and maybe a ring gauge on a stick to check the groove depth and width. I's also go slow with the drilling and boring ops as the hold on thin straps is not as good as on solid bar.

JD

I wrote I how I made some for my Easton & Anderson recently may be of use, see here

It's not a very specific description, Jeff

... but this might help.

MichaelG.

Well OK Michael I get that the original castings "got messed up". I also see that Jason made a beautiful job of his, as usual. It sounds like Bill used much the same method as Jason used, but had different results. Still not sure what problems Bill had, specifically, to be able to offer many suggestions.

Bill, you are not alone in having troubles the first time you make a tricky part. On most moels I build there are always a few jobs that end up redone and the first attempt goes in the scrap bin. However the more jobs you do over a long time, the less goes in the bin, eventually. I build most of my models without castings for this reason, as a bit of bar is usually so much cheaper than a casting.

JD

That's a new one on me too. After 10 years in engineering and 35 years in education plus a few holiday jobs on building sites I thought that I'd heard it all, oh well! not sure what the D-W is either , I'd try to help if I could really get to grips with the problem or someone could translate.

Regards

T

Thank you Jeff, Michael and Jason.

Jeff, your reply was most reassuring. Working in isolation it is easy to assume that 'the experts' will have much better ways of doing things. In my case, generally true but it sounds as though it wasn't too nonsensical. Jason's method looks absolutely superb, altghough in my defence, my original eccentric castings had the conn rods cast in which made holding in the 4 jaw essential and checking bore sizes fiddly and (ultimately) flawed!! Also the bores were about 3/8th" so not easy for 'fumble fingers'! By the way, Jeff, you were absolutely right on all three of your guesses as to the problems

Ah well, onwards and maybe upwards but possibly 'back to square one' .

Exit left, muttering "It's a hobby, it's a hobby ... etc., etc,

Rgds

Bill

Apologies Terry et al

Too many years in a Service environment where 'in house' slang avoided the need for 'expletive deleted' and D-W = Dore Westbury. Keep forgetting that just because it makes sense inside my skull, the rest of the world isn't in there seeing what's going on - probably just as well !!

Rgds

Bill

"Exit left, muttering "It's a hobby, it's a hobby ... etc., etc,

Rgds

Bill"

Careful with muttering that mantra over and over if you eat rice for supper - you may have a sudden urge to wear an orange robe and sit cross legged on the floor a lot while saying the mantra.

Anyway good luck in round 2 with your eccentric straps.

JD

PS - forgot to mention that the way I guessed some problems you may have had on the first attempt was they were all the same ones I had on the first ecc straps I made - needless to say mine were FUBAR and the best thing I can say about them is they had a lovely final trajectory into the scrap bin.

Edited By Jeff Dayman on 26/11/2012 22:27:09