line lap question

[JR JOHNSON]

hi,on my 59,I'd had to pull my crankcase apart,rod bearing prob,long story,I'm replacing the flywheels,crank pin to deep no rod side play,reason for failer,but my right case bearings are .0008,but my question is should i have the shop run the right case on there sunnion hone a little bit to clean it up,get some cross hatch in it, but it will be free hand,the bearing looks good,but I'm not sure free hand is a good idea.no body around here have no lapping tools,the old school shops are going away,or there dieing off.I'd tried searching first so i would half to bug you guys. any ideas would be appreciated, thanks.....with respect.....JR

[Cotten]

Jr!

A Sunnen and a common lap are from two different zodiacs!

If your honemeister has the proper gauging instruments, and appropriate rollers are available,...

then "free hand" is exactly how I would do it,...

again,....

as I did so many times in the past.

My only disclaimer is that a lot depends upon the mood of your honemeister! (Nevermind all that other stuff like case stress and whatever. That's not a practical concern!)

....Cotten

[JR JOHNSON]

thanks cotton! the machine shop friend never done it before,so I'll get a crash coarse on the sunnen lapping machine,do it my self,old dog learning new tricks .thanks again...............with respect.....JR

[Cotten]

JR!

The advantage of doing one case over a pair is that you can 'stroke' the hole from both sides to alleviate any 'bell-mouthing' or tapering.

If the boregauge shows a narrow tight spot, then just that portion of the race can be stroked with a stone that has been shortened by clipping off the ends of its abrasive portion.

Sunnen's operation literature encourages such creativity!

Good luck,

....Cotten

[JR JOHNSON]

thanks again cotten! oh ya a beer,if i make it to your neck of the woods one day........with respect.....JR...sorry about miss spelling your name,must be my 3rd grade education!see ya...jr

[JR JOHNSON]

cotten,what stones grit do you use,also what speed? thank you for the help,sorry to bug a on this,just never lap before,again thanks.......with respect..............JR

[Cotten]

Jr!

My Sunnen only has one speed.
Its all about History to me, sorry.

With a Sunnen P58 mandrel,
I used (emphasis on past-tense) an A55 stone for the 'rough' cut,
followed by a J85 stone 'finish' cut,

and then plateau-finished with an ADALOX impregnated nylon "tube brush".

It's all about your bore gauge,... really...!

....Cotten

[JR JOHNSON]

COTTEN,ran the hone threw the bearing,both ways,just a little,with a fine stone,look even,no low,high spot,so i left it alone,but he didn't have bore gauge to work in the bearing,but I'm happy with it,thanks again for the help....with respect...JR

[indianut]

Sorry, but using a Sunnen Hone without a Bore Gage is like using a Ball Peen hammer without a Handle!

[Cotten]

JR!

Didn't he at least have a snap-gauge and a mic?

....Cotten

[JR JOHNSON]

hi,only tipe of snap gauge he had was a t snap,them phony tip of snaps,I've have a inside mic i used before i took it in,seem OK,but the hone marking were Evan across the bearing,I'm OK with it until my assortment of bearings show up,to plug fit,I'm the one making the decisions,and on my own,going by gut feelings on it,thanks for your help,and concerns..........with respect.JR.