Welding a Sunnen honing adapter

Sunnen honing adapters (e.g. K6-A, K8-A, AK20-A, etc.) are non-magnetic. Has anyone ever successfully welded to them and, if so, what TIG filler rod works? I'd like to adapt an old one to hold a small 3-jaw chuck for external honing and starting from an existing adapter would be faster than machining one from scratch. Thanks in advance for any help.

NON magnetic, is a bit open, care to try and narrow it down any more? Anything short of some kinda zamak like casting is genrally pretty weldable.

If its some kinda powder metal component, then i would not advise welding, but brazing with correctly designed joints works well. Though if the parts been oil soaked, it can need a high temp burn out - off with a gas torch first. Some powdered metal parts can have significant porosity, even if there not designed too.

adama said:

NON magnetic, is a bit open, care to try and narrow it down any more?

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I was being deliberately vague so as not to betray the fact I think they're Al, not steel or cast iron. I was hoping for independent confirmation of this. They're less than RocC 40 and don't give off any sparks at the grinding wheel.

Sunnen sells a drill chuck for their machine. Works fine for holding needle eye laps etc.

Red James said:

Sunnen sells a drill chuck for their machine. Works fine for holding needle eye laps etc.

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I have one of their Jacobs chucks but want to be able to hold motorcycle fork tubes which are of larger dia. Sunnen's 3-jaw chucks are seriously pricey, but I have a perfectly good small chuck for the purpose and only need to modify/fabricate an adapter for it.

Most of the Sunnen shanks I have seen look like the dreaded Zamak. You want to mount a chuck on the machine instead of a hone?

magneticanomaly said:

You want to mount a chuck on the machine instead of a hone?

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Yes. In additional to the "standard" hones for holes Sunnen makes a set of external hones for dealing with shafts, along with a 3/4" Jacobs chuck and 5" 3-jaw chucks for holding them.

They are die cast. If you want to hold something as heavy as a three jaw chuck you would be better to start with something stronger

gappmast said:

They are die cast. If you want to hold something as heavy as a three jaw chuck you would be better to start with something stronger

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The cross section of an adapter is much larger than that of any weld to its circumference so the strength of the weld will be the limiting factor, not the strength of the adapter. Assuming it's definitely Al, which gets me back to my original question.

Dicast you have 3 options, magnesium, zinc - zamack or aluminum. Some of the alloys contain all 3 to varying degrees, but so long as its not zamack its weldable, zamack feels noticeably heavier than a similar sized lump of aluminum, nearly on a par with steel. If you can even approximate its volume working out its density should narrow it down into likely to be weldable or not.

Lots of the casting grades of aluminum generally weld very nicely as a rule of thumb, if you consider what makes good casting properties wise of going from liquid to solid, casting grades of metal generally makes for nice welding properties, (exception of iron) its the extruded grades that are normally the bigger issues, though most can be welded pretty reliably these days too.

This would probably be a bad idea if your going to spin the chuck fast, but my understanding, your going to be in the low hundred rpm range, so even if it fails, its not going to be seriously dangerous. If you do want to go fast, then it probably would be better to look at a solid steel part - back plate. Aluminum has a very definite fatigue life, especially when your playing - welding with uncertain alloys.

adama said:

This would probably be a bad idea if your going to spin the chuck fast,

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I don't have steel pipe in the right size so my question was just to save me the effort of boring a hole in a solid bar (needed for the Sunnen's internal mechanism). However, I found a length Al rod so I'll use that. It never will have to hold much weight so Al will be more than strong enough for the task.