sunnen tooling - sleeves and mandrels

[Mcgyver]

any of you guys had a go at making sunnen mandrels?

and the truing sleeves - what are they made of and how do they work? if you don't have a sleeve is there a work around or can they be made (not sure how they dress the stone)

thanks

Oooops, not sure how two threads got posted, can one be deleted? thanks

[Forrest Addy]

There's no reason ast all why a home shop worker seeking to save a few bucks can't reverse engineer Sunnen honing mandrels and sleeves. It's plain old machine work. Measure and make.

The truing sleeves are simple: they are cast iron sleeves with a bore about the same length as the homing unit they accompany. The official Sunnen sleeves have longitudinal ribs to gine a good grip for the user and are drilled for oil circulation; otherwise most any hunk of cast iron bar would make a good truing sleeve.

[Mcgyver]

The truing sleeves are simple: they are cast iron sleeves with a bore about the same length as the homing unit they accompany. The official Sunnen sleeves have longitudinal ribs to gine a good grip for the user and are drilled for oil circulation; otherwise most any hunk of cast iron bar would make a good truing sleeve.

thanks Forrest...what i don't understand is how the truing sleeve works, ie how is it able to 'dress' or otherwise remove material from the stone rather than the stone just honing it?

[Forrest Addy]

That's it. The bore size of the truing sleeve is sacrificial. It enlarges as it conditions the stone/bearing surface of the hining unit. This way a new unconditioned stone won't be used on a nearly finished bore.

A honed bore is "generated" that is the roundness is not an artifact of the rotating axis but the averaging of errors the honing action employs when sizing a bore. The honed bore follows the net axis of the rough hole but the controlled wearing away of the honing stone and the guide shoe plus the amount of over travel and other small factors combine to chrate a nearly perfect round hole on a produstion basis.

[Mcgyver]

so the truing sleeve is primarily used to round over a freshly installed stone?

another Q, is the mandrel articulated somehow to the spindle or rigid? video's i've fiybd suggest its rigid. What's it like working with something heavy such as a 10ee tailstock...its going to be impossible to hold it perfectly steady so ideally the mandrel can float a bit? Its the older model LB I'm thinking of.
thanks

[Forrest Addy]

Yup. The honing unit typically has a U joint where it joins the driving shaft. If hand manipulated the operator ensures the drill is held more or less on the bore's axis.

One thing to consider. a honed hole follws the existing hole. enlarging and rounding it but does not necessarily stay in alignment with any other feature. If you hone the bore of a 10ee taistock you can bet the bore will drift somewhat necessitating a re-scrape of the base to restore the quill bore alignment and maybe a shim netween base and upper casting to raise it to the spindle axis.

Another point is a tailstock quill has a long bore. Long bores and short hones are a recipe for barrel shapes. Watch overt-ravel and time spent concentrating on any one part of the bore. Check frequently with a dial bore gage. If there is a keyway, fill it flush with material having the same characteristics as the parent metal.LockTite (use the weak stuff) it in but tap it for a pair of jacking screws for removal. Same goes for the quill clamp slot or intersecting bore.

IIRC a 10ee quill is fitted 0.0003" to 0.0004" loose. If that's the case the tailstock bore for the quill has to be round and straight witnin less than 0.0001" This is not difficult with a Sunnen hone but you do have to watch the variables.

[Mcgyver]

the internal laps I've made sort of do the same - I believe the closely follow the existing hole but I don't really have a way to quantify. My thought was the Sunnen honing machine would work in a similar way but probably do a bit better job because it has a longer reference surface. The hope is to get perfectly straight bores, no taper. That becomes my starting point in that I know no way to get a perfectly straight bore perfectly parallel to something else. Will scrape the bottom of the tail stock parallel to where ever the bore ends up

Need to do two tailstocks, a 10ee (heavy!) and a maximat. I'll grind the barrels after hard chroming and everything else will follow/reference that

Just so I'm clear, on the honing machines with mandrel; they're have a universal joint? Or are you referring to the Sunnen one's used in a hand drill? From pictures/videos it doesn't seem like there is much movement on the honing machine mandrels. If they are rigid I'm not sure if i can stand there holding up the 10ee tailstock and keep it steady long enough not to make a mess.

[Forrest Addy]

If you have access to a real honing machine they will hove double universals. The Sunner horizontal hone found in so many automotive machine shops have arigid spindle holding the honing unit but there is radial adjustment to center up the honing action. Some form of weight balancing makes honing heavy awkward parts much easier on the Sunnen horizontal hone. Getting a 10ee tailstock quill bore right is a high consequence operation. It pays to take pains gettting it right.

Just betwen you and mee, I always had difficulty with sized bore laps. I always got the bore a litle bellmouthed. Honing I could always get a crisp straight bore but lapping? Not so good.

[Rustybolt]

Just so I'm clear, on the honing machines with mandrel; they're have a universal joint? Or are you referring to the Sunnen one's used in a hand drill? From pictures/videos it doesn't seem like there is much movement on the honing machine mandrels. If they are rigid I'm not sure if i can stand there holding up the 10ee tailstock and keep it steady long enough not to make a m

The last Sunnen hone I owned was a 1600 and it didn't have a universal joint. I think that is the hand drill operated one. There is adjustment on the machine to advance the the stone in the mandrel and another adjustment for honing pressure on the stone. The mandrel size should be as close to the bore size as possible that allows he mandrel to rotate freely.
There are internal angles in the mandrel that correspond to angles on the stones. I'd think those angles would be hard to duplicate.

[Mcgyver]

Just betwen you and mee, I always had difficulty with sized bore laps. I always got the bore a litle bellmouthed. Honing I could always get a crisp straight bore but lapping? Not so good.

sounds like this little machine i'm looking at is not the right tool for the job... it would be fine on something small that could float but not a heavy tailstock. As you say a high consequence job.

I can't compare my lapping and honing abilities as I've never run a hone . I have had good results from lapping. I recently had to lap a hardened gear in the 10ee backgear (ground a new shaft to fit the then round bore) and for kicks tried to see how perfect i could get it. Got it to 2 micros consistent diameter using a mitutoyo bore gauge, gear/sleeve was maybe 2" long. To get it that good (which was far more than tight sliding fit required) required some iterations of measure, lap etc. In other words couldn't do it by feel alone. I did get it to 5 or 6 microns if I recall though by feel...with fine lapping compound i find you can really feel the tigh spots - this is done with work in the lathe and the lap hand held, essentially floating. Also, I've never tried to lap to size, just to round and straight and just made the mate to match

It would be an interesting project....a socket set universal joint might be employed, with a tube encasing it so it can fly about wildly if you exited the bore...hmmmm

I'm thinking the right tool for this job may just be an expanding lap, perhaps a little longer than what i've done in the past, a U joint and an electric drill.

[Forrest Addy]

No, Ypu can do the job in an hour or so with the right hand drill powered equipment. I checked locally and a couple of places have unit, stones, and driver for rent but the 10" long honing unit has to come from out of town. They need a couple days. That's 10" of actual honing stone length (multiple stones).

Wish I could run a little cvlinic on honing.

Do what's comfortable for you but if you never honed a round straight bore maybe now would be a good time to gain the experience. How about this: machine a sleeve having the 10ee tailstock bore? Practice on it.

[rowbare]

Mike,

Have you seen TexasTurnado's SAG Rebuild on PM? Starting from about page 20 he shows how he lapped the tailstock bore. http://www.practicalmachinist.com/vb...0/index20.html

bob

[Mcgyver]

thanks Bob, lots of good content there. I couldn't find where it specified, but it looks like its a cast iron internal lap? If he's charging the lap and then using it as a cutting tool I get it, but if he's running loose abrasive i'd be concerned that it would partially get embedded in tail stock casting...ie better to use a softer lap than the work

Forrest, I've read many times your views on internal lapping. What type of laps would you have been using? The reason I ask is what i do uses a combination of a charged lap and rolling action with the lap a lot softer than the work. What happens is the lap is fairly sacrificial, or at least the out copper skin is, and it is expandable. I believe it wears into a perfect cylinder because of this action (ie what other shape could result). As a perfect cylinder, it also acts as a guide and hot spots along the bore are readily felt. I wondering if your lapping work used the same type of tackle and if not if that accounts for my sense that it does work well?

I can quantify roundness and a consistent diameter in that regard and believe I can lap to a tenth if I'm careful (and hold my tongue just so). What I don't know is whether its banana shaped. I believe the lap itself acts as a guide and that it tracks the original bore quite well, but i don't know. Short of grinding up carefully sized bars that could easily become very hard to remove, any tests you can suggest?