Material for Small Pins, Heat Treat Concerns

[EmGo]

I'm looking at a '97 Hardinge GT27SP this week for $6k ...

Expanding ! Cool. Wasn't it just a short time ago you were thinking about getting into your own production ?

Time flies when you're having fun

 

[Rick Finsta]

Yeah... when I first joined, I had just moved from scientific instrumentation into CNC machining. I rehabilitated a shop for some new owners, and then moved on to my own shop when I bought a product line. I've been bringing more stuff in-house and onshoring hardware and such. CCA Racing Products is the brand - torque plates and hand tools for engine rebuilding. I'm in the last stages of redoing the website ready for a September 1 launch, and I'm down to the last tool redesign. I'm also trying to negotiate a few distributors internationally.

I looked at the GT27SPs this morning and one is coming to the shop. I got a pair of the quick change top plates so I'll be able to leave product hardware jobs set up. I will have to make a few tool holders but otherwise it should hit the ground running. It was funny to see millionths on the offset page LOL.

Should be early next week I get these pins back and I'll let everyone know how it goes and which way I head from here.

 

[Rick Finsta]

Well I thought I already posted this, but evidently not!

Pins came back yesterday and they actually had a very nice uniform gold color to them. I think it looks really nice but doesn't really match the tool bodies. So, a few seconds with a hand drill and a piece of scotchbrite polished them right up.

Thanks for all the help and suggestions. Looks like cutting off blanks of the McMaster A2 drill rod and then hand feeding them through the lathe is the way to go, followed by heat treat to full hard and then a trip through the polisher.

 

[BoxcarPete]

Full hard? Looks like those were tempered to 400°F or so based on the color, should be down to 62 HRC.

Edit: you probably meant through hardened

 

[TDegenhart]

Consider a vibrating tumbling polisher. Throw a handfull in, turn on the machine and in an hour nicely polished parts.

Tom

 

[Rick Finsta]

Full hard? Looks like those were tempered to 400°F or so based on the color, should be down to 62 HRC.

Edit: you probably meant through hardened

No they told me they skipped normalizing because they said it would have scaled the parts (they heat treat in vacuum but don't normalize in a vacuum I guess?) and we wanted to keep the surface finish.

 

[Rick Finsta]

Consider a vibrating tumbling polisher. Throw a handfull in, turn on the machine and in an hour nicely polished parts.

Tom

I'd just use the same setup I use for processing metallic cartridges for reloading. The oxidation on these will rub off with a finger without too much effort so I would not want to use any kind of aggressive media.

 

[plastikdreams]

Looks great!

 

[CorePin]

Nice lathe! Haven’t heard that name since I was an apprentice moldmaker about…….a while back. Some of the work our lathe dept. manager put out on the old Leblond Regal blew my mind! Guess I was lucky to do my apprenticeship in a shop with a good lathe!

 

[CorePin]

Default
I appreciate all the replies. I meant to post a picture for size and use reference and got a customer call so just hit "post."





Here you can see it just needs to be straight enough to be coaxial with the dial indicator. It would have to really banana to cause issues, I think.



Quantities to start off with are projected at a few hundred a year. I am cutting them to length (plus facing stock) and then sticking them in a collet, machining the first side, M00, manually flip it, then machining the second end. I originally intended to hard turn material, but I do have concerns about the machine being capable (this is on my archaic Takahashi gang lathe).

Why hardened? Partly because "that is the way the old owner did it" but also because I don't want the anvil to distort against the thumb screw over time, and I don't want the radii to wear on rod bolts over time. Making them hard removes the concern.

The heat treater is picking up some to test today. He doesn't expect problems due to the short length. Biggest issue is they will have scale on them afterwards, and I'll have to try tumbling them and maybe polishing as well.

If I can't get pretty parts this way, I will look into the 17-4 prehardened. I don't have the SFM to run CBN but the Sandvik rep got me a few inserts to try out in up to 60HRc at the speeds I can run.

Again, I appreciate all the information.

I laughed when I saw these pics…..HARD! The first few replies to this post were all on the same train of thought as I. We all thought, since you did use the word taper, was that you wanted to make your own specialty “Taper Pins” which are typically used to lock round parts fitted through another part vertically, such as a gear on a shaft. What you have there is an angle down to 1 mm radius. My question is this. What is the thumb, set screw made of and is it hardened?

 

[plastikdreams]

I'd just use the same setup I use for processing metallic cartridges for reloading. The oxidation on these will rub off with a finger without too much effort so I would not want to use any kind of aggressive media.

Just for shits n grins, have you compared:

the cost of a2, making the parts, heat treating, and finishing

vs

cost of prehardened 17-4ph and machining?

It would be interesting to see.

 

[Ianagos]

Just for shits n grins, have you compared:

the cost of a2, making the parts, heat treating, and finishing

vs

cost of prehardened 17-4ph and machining?

It would be interesting to see.

That was why I recommend 17-4 figured the hassle would be less and the material turns beautifully.

No polishing after heat treating nonsense and no having to send the parts out for heat treat.

 

[plastikdreams]

Yep I agree

 

[Rick Finsta]

I laughed when I saw these pics…..HARD! The first few replies to this post were all on the same train of thought as I. We all thought, since you did use the word taper, was that you wanted to make your own specialty “Taper Pins” which are typically used to lock round parts fitted through another part vertically, such as a gear on a shaft. What you have there is an angle down to 1 mm radius. My question is this. What is the thumb, set screw made of and is it hardened?

Set screws are from McMaster for the first run, unknown non-magnetic stainless, and I'm turning the shank down a bit on the manual lathe just so they fit in the holes. The swiss shop next door is going to run them after that I think and we were thinking 303 since they stock 1/4" TG&P so I can get them on short(ish) notice.

 

[Rick Finsta]

I'll check out the 17-4 option and report back.