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Honing Tailstock Bore: Is a portable Sunnen adequate?

CountryBoy19

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Aug 14, 2012
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Bedford, IN
I have the chance to pick up a portable Sunnen hone set with nearly a dozen stones for a stupid cheap price...

I may end up rebuilding my tailstock at some point, including boring and honing. Will the Sunnen portables do an adequate job or does it have to be the stationary units that are rigid setups?

ETA, this would likely see more use than just a 1-time tailstock hone-job. The price to get into a Sunnen hone is usually cost-prohibitive so I've never considered it. Even the portable I'm looking at sells for ~$500 on ebay with only a handful of stones. Am I thinking correctly that if one can be had for a fraction of that it would be stupid not to get it?
 
I have the chance to pick up a portable Sunnen hone set with nearly a dozen stones for a stupid cheap price...

I may end up rebuilding my tailstock at some point, including boring and honing. Will the Sunnen portables do an adequate job or does it have to be the stationary units that are rigid setups?

ETA, this would likely see more use than just a 1-time tailstock hone-job. The price to get into a Sunnen hone is usually cost-prohibitive so I've never considered it. Even the portable I'm looking at sells for ~$500 on ebay with only a handful of stones. Am I thinking correctly that if one can be had for a fraction of that it would be stupid not to get it?

Ive seen a couple videos on honing a TS bore. Don of Suburban Tools did a grinder TS on honing machine. Theres a Storebro video that shows them using a portable hone to finish up. A buddy with an engine shop honed mine for me.
If theyre cheap why not grab them.
 
What model Sunnen hone is it, AN JN SN, and what is the size of your tail stock bore?

It's an AN... I'm thinking it's a tad too big for my 2.25" tail stock bore but I may be able to trade or sell it and buy smaller. Either way I think the posts have pointed out the obvious, if it's a good deal I need to get it even if it won't do my TS.

I can't find any reference to the model from sunnen so I'm not sure how small it will go but its coming from a shop that did small engine and automotive work... at this point I haven't yet seen it, just a picture of it.
 
Only reason I'm bringing this back up is bc I have a question. I was under the impression I would have to make a filler for the key way before honing but apparently Sunnen makes hones specifically for bores with key ways. Is there any reason that wouldn't work out well? Unfortunately they don't make them for the JN series which is what I would need unless I were to oversize my bore enough to work with the AN series. I would have to check into that more before going down that path... mostly just thinking out loud.

That being said, I bought the AN series. Comes with an extension and quick coupler on the shaft. Included 11 sets of stones/guides ranging from a couple well-worn and/or chipped up to 5 or 6 sets brand new. It was a local auction, I figured I could get it bought pretty cheap. It wasn't as cheap as I had hoped but still a good deal.
 
Only reason I'm bringing this back up is bc I have a question. I was under the impression I would have to make a filler for the key way before honing but apparently Sunnen makes hones specifically for bores with key ways. Is there any reason that wouldn't work out well? Unfortunately they don't make them for the JN series which is what I would need unless I were to oversize my bore enough to work with the AN series. I would have to check into that more before going down that path... mostly just thinking out loud.

That being said, I bought the AN series. Comes with an extension and quick coupler on the shaft. Included 11 sets of stones/guides ranging from a couple well-worn and/or chipped up to 5 or 6 sets brand new. It was a local auction, I figured I could get it bought pretty cheap. It wasn't as cheap as I had hoped but still a good deal.

How wide is the gap?
 
This is an interesting issue.

Afaik hones make about 0.01 mm in size and about 0.0005 mm tir/finish, generally.

As measured over some limited size, some limited length.
Afaik rigid hones tend to make pretty/very good cylinders and can control the size to about 0.01 mm, or a bit better.

Imo, ime, a ts bore of say 30 mm might be 150 mm deep, more or less, on D and depth.
12-13" lathe.


So what actually happens when honing such a (pass-through) hole ?

Does the hole align to the hone, and if so how do you set it up that well ?
(Like line-boring, conceptually).

Or does the hone make the existing bore more round, cylindrical, uniform, but follow the existing hole.
How much does it bell-mouth ?
(E. 30 mm / 150 mm).

E.
If one aligns a TS aka cylinder on a rigid honing machine, top and bottom, to less than 0.01 mm error in alignment over 150 mm length.
Is this reasonable ?

After honing, what might be the accuracy in size of the bore ?
 
When you hone a hole something has to float. If you try to hold both part and tool ridged you are going to get terrible geometry.

By controlling the over stroke of the hone you will have no bell-mouth.

The hone is going to follow the center line of the existing hole. If the existing hole was out of round the hone it will make it round. If the hole was tapered the hone will make it straight.
 
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How wide is the gap?

.250" I think. Of course this is just an educational discussion at this point bc they don't make stones for key ways in the JN hone which is what I would need. The GY series stones which are for 2.5"-2.7" bores on the AN have a max key way width of .8".
 
The 1¾ - 2¼” junior hones can work with a 1/4” slot, you just use 4 stones instead of 2 with the 2 wipers. You’d need to wear it in a hole SMALLER then the hole you intend to touch up. The wipers don’t like the split line for clamping either...

I think you were involved helping a guy with a graziano sag tailstock, didn’t he end up boring and trying to lap it?

Good luck,
Matt
 
The width of the stones for the JN95 hone are about .320". They will most likely work if you can live with a little washout by the slot. The best accuracy you can expect from the AN or JN hone is .0005" Sunnen will not guaranteeing anything better.

On the educational side there are ways to hone this hole. Sunnen makes a key way mandrel that is designed to bridge up to a .625" slot in that diameter. The key way mandrel could be used in one of three ways. If the tail stock is manageable, weight and size, the tool could be put in a Sunnen pedestal hone. Another way would be to put the key way tool in a Sunnen CV616 vertical machine. The third way would be to put the key way tool in a GGN150 portable mandrel driver and hone the part with a drill motor, like you would with a AN or JN hone. The standard key way tool in that diameter range has a total reach of 7.5" which means you could hone a part up to about 6.5" all from one end. If you want to hone from both ends the part could be up to about 12" long. Roundness with the key way tool will be a tenth or two.
 
Thanks !
Absolutely excellent response.

When you hone a hole something has to float. If you try to hold both part and tool ridged you are going to get terrible geometry.

By controlling the over stroke of the hone you will have no bell-mouth.

The hone is going to follow the center line of the existing hole. If the existing hole was out of round the hone it will make it round. If the hole was tapered the hone will make it straight.
 
Sunnen will not guarantee anything better because with a hand held tool, so much is dependent on the skill of the operator and measurement. I have used a JN for years, and can hit 2/10ths all day long on 2-2.25" bores if careful. This is in cast iron or ductile iron.
 
Wasting your time honing. Likely the bore is out of round, tapered and skewed to the base. A hone will only follow what's there, good or bad. As mentioned, if a keyway or interruption, near impossible to hold size. There's a reason these are jig bored and ground to size.
 
Wasting your time honing. Likely the bore is out of round, tapered and skewed to the base. A hone will only follow what's there, good or bad. As mentioned, if a keyway or interruption, near impossible to hold size. There's a reason these are jig bored and ground to size.

Numerous other posters seem to disagree with you. Out of round and taper is exactly what a Sunnen hone will correct.

That being said, in my case, you're correct about the bore being skewed to the base. But that's not always the case; and there are other means for correcting that as well. In my case my full plan was to bore in-situ on the lathe using 2 steady-rests as location guides, a piece of TGP round for boring bar, a thrust-bearing on the carriage to move the boring bar, and a slip-joint run from the headstock to drive it... that method was discussed in-depth in a prior thread and was regarded as a viable in-place repair method. The honing would only be to ensure roundness and obtain surface finish.
 
Sunnen will not guarantee anything better because with a hand held tool, so much is dependent on the skill of the operator and measurement. I have used a JN for years, and can hit 2/10ths all day long on 2-2.25" bores if careful. This is in cast iron or ductile iron.[/QUOTE

Sunnen will only guarantee .0005" roundness with the JN hone because of the design with diametrically apposed stones. You may measure .0002" roundness measuring at two points. The same part measured with more sophisticated roundness measuring equipment will show greater error.

The style of mandrel that is used in a honing machine is different, with 2 guide shoes and 1 stone. The spacing of the guide shoes and stone are engineered to make rounder holes.
 








 
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