Threaded Mandrel for Unimat SL Chucks

[PJs]

Thanks Paul, I contacted Peabody on the Inconel and Hastelloy but even his memory has some slippage. Not sure how much they are actually used anymore because of the exponential strides in material sciences but yes they are a bit tricky and unforgiving to work. Mainly they are used in high heat, nasty (corrosive) environments as you probably know from your background, primarily because of the high nickel/chrome content. Hastelloy has moly/tungsten as well and maybe more challenging to work than Inconel in conventional machining operations.

In this case it was to work tubing of various diameters and wall thicknesses. Part of the reason for successfully working these materials was the Desouter drills were driven by VFD's fed by code (RS-485) and had the ability to peck and dwell by code as well. The difficult thing was to figure out the speed/feed/peck and dwell for each operation, material and size/wall. I developed a spreadsheet the size of Rhode Island, barely legible on "B" size paper and probably 10+ sheets, for all the tools and operations so I could develop the code...but I digress.

Basically I could develop a starting place for each op mathematically, but as we all know its only a starting place to hone in on the requirements. So I did a bunch of tests on small pieces until I could get the desired results, clean hole sizes, finishes and accurately placed. The 1" and 3/8" insert ball end mills were Kennametal and I spoke with their AE (applications engineering) people to get the right inserts for those two materials, to get a modicum of life out of them. They were coated Tialn if memory serves, but may have been Ticn. There was also medium size drill that I used carbide end mills on to create a flat and port. The carbide circuit board drills on the small drills held up pretty well once I got the feed rate dialed in and spun them pretty fast ~10-15k because they were small and 4 flute, IIRC. They would eventual fatigue and bink, but cheap compared to the inserts for the ball end mill which held up really well over many, many runs. And as a bonus, the inserts worked wonders on the stainless, Al and CU runs which were more common. The 5 materials and all the sizes were the real challenge to speed/feed, to peck or not to peck and try not to dwell on it to keep the machine speed up.

Bottom line for Inconel and Hastelloy IMHO, is multiple pecks and a light (short) dwell at the end for a finish and good, Solid work holding...with the right tooling of course, including the ER 32 collets to hold them. Also I had built in a flood coolant system to help flush and cool. Don't remember the coolant type, only trying to get people to change it regularly! @¿@ Nothing like the smell of bad coolant on a hot afternoon. That was 3 years of 50-80hr weeks for Peabody and way back machine in a few paragraphs. Hope that helps.

Yes, the 5C collet system has many versions to hold different types of cross sections and come in Imperial and metric dimensions. I especially like the expandable collet design to hold parts by the ID just like an expandable mandrel but much faster with the open and close cycles.

I also like that ID/OD holding feature for collets. Way versatile! This Old Tony has some collets for his lathe that I think he shows in his CNC build(?) that are quite interesting and appear they would be quite accurate by design...but old school I think...worth a look.

Always enjoy your threads...Peabody too! ~PJ