Excentric straps and cams

i have noticed the excentric straps and cams bind when the straps are done up. is this because the inside surface on the straps is rough and needs a polish or do i need to use some shims between the two halves? has anyone else had a problem with these? do i have a set of unfinished straps or should i polish the inside surface. If the inside surface needs polishing can some one tell me the best way to do so.

making slow progress but will all look very nice when done!

Thanks in advance
Jon

Hi I had some burrs in mine so I rubed them out with 1200 grit .

YA, GOT THE SAME PROBS WITH OURS, EVEN AFTER MAKING SURE ALL BURRS ARE SORTED. WILL BLUE THEM TO SEE WHERE THE TIGHT SPOTS ARE. WILL GET THEM RIGHT.
BUNGLE

Best to put shims between the straps as these can be removed as the eccentric wears. If you must use grit make sure you get every last trace off otherwise there will be a high rate of wear.

Julia wrote:Best to put shims between the straps as these can be removed as the eccentric wears. If you must use grit make sure you get every last trace off otherwise there will be a high rate of wear.

Yes thanks I should of said that .In my case I used meths and then water running from the tap

good to know i am not the only one with this problem, i have now got the first one finished but it took alot of work...

THANKS JULIA,

GOOD IDEA, WILL GO THAT ROUTE.

BRUCE

FOLLOWING JULIA'S SUGGESTION, I MANAGED TO GET A HOUR TODAY (WORK KEEPS GETTING IN THE WAY !!) TO TRY SHIMMING THE STRAPS. I GOT UP TO 0.247mm ON BOTH SIDES OF THE FIRST STRAP, AND THOUGHT THAT WAS MORE THAN I WOULD FEEL EASY WITH. SO WENT BACK TO BLUEING THE INSIDE OF THE STRAPS AND FOUND IT TO BE BINDING ALL AROUND THE INNER RECESS, SO HAVE TRYED TO EASE THAT AREA SLIGHTLY. NOT HAD TIME TO REFIT AS YET, BUT IT STILL GIVES ME THE CHANCE TO SHIM (ALITTLE !!) FOR FINAL FIT. I COULD OF COURSE CONSIDER THE ECCENTRIC ITSELF AS WELL.

KEEP YOU POSTED

BUNGLE

Good luck with the shims

GOT THE TWO VALVE GEAR ONES RUNNING OK NOW. THE PUMP ONE HAS A SLIGHT TIGHT SPOT THAT I'VE SHIMMED OUT WITH 0.07mm SHIM, I FEEL THAT IT WILL BED IN AFTER A LITTLE RUNNING (MAKING SURE THAT IT DOES NOT RUN HOT !), AND I WILL BE ABLE TO REMOVE THE SHIMS IN TIME.

BUNGLE

the straps are ment to be shimmed really to get a perfect fit. there's prob not one full size steam engine that doesnt have shims on the straps..

I think I mentioned this some were in another post..

Jo