Fairly new to A2 and progressive die process

[dforsythe]

Material is A2 1.250 x 6.5 x 14.25

 

Mill 1.00 thickness to +.015

Mill complete less threaded holes and 4 x .5000 slip fit hole ( note many dimensions have a +/- .001 tolerance )

Heat treat to rc60

Grind top to get all edges sharp

Thread the holes and ream the 4 x .500 slip fit

 

Any thoughts on this.  It’s not really something I have done before, but it could open doors for more work down the road.

 

Thanks, Damian

[Matthew Hajicek - Singularity]

Get your feed and speed from HSMAdvisor.  I believe they have a limited free trial.

 

They want the holes threaded after heat treat?  That means threadmilling.

[Del.]

I don't see why you couldn't thread the holes before H/T but I would wire edm the slip fit holes for location.

[Allan]

A2 is very stable in Heat treat.

Threaded holes and reamed holes always done before heat treat in A2.

Typically the reamed holes are transfer punched into the die shoe on assembly.

 

JM2C

 

Allan

[dforsythe]

thanks for the info guys.

 

like I said, never done this type of work before and was more wondering what the industry standard / flow of operations were.  I would love to finish it all, then heat treat and grind, but I think its safer to try and hard mill the critical features.

[Thad]

I've been working in die shops for 20+ years and have never seen a detail processed like that before.

[mikenaturalice]

You are not going to ream anything at 60rc IMO. I would drill the dowel (I presume) holes with an 1/8" drill and wireburn after HT and grinding is done. You can drill and tap the holes before HT, they will not move enough to cause an issue, if they move it will be very minimal. Maybe oversize tap them if you want, but you don't really need to for A2.

[Müřlıń®]

A2 is very stable in Heat treat.

Threaded holes and reamed holes always done before heat treat in A2.

Typically the reamed holes are transfer punched into the die shoe on assembly.

 

JM2C

 

Allan

+1

 

I made a few progressive dies...A2 is the most stable material there is during the heat treat process.

 

Our rule of thumb was to never heat treat A2  with a sharp corner as it will develop stress cracks. Especially on thin trimmers...but some shops didn't follow this procedure....I always went ahead and reamed the trimmer dowels with a .0005 under reamer and tapped all the holes before heat treat as the bolt holes weren't really a stress point...

 

60RC is a little brittle for me I always tempered to 58.

 

And yes you can ream 60RC.

 

We made the trimmers from A2 and use D2 for the punches.

 

We omitted the dowel holes in the punches and bolted everything up and had a press to run samples...one we had all the components lined up and making burr free parts we flipped the top plate over and doweled the punches in place with carbide reamers.

 

I made a die that stamped .005 SS...the punch/die clearance was almost metal to metal....

 

There is a process you must go through to make a progressive die...you cannot just machine all the parts and expect them to all fit in the die set properly...they must be "fit" if you are stamping very thin material.

 

.06 ss has .0035 per side clearance so you can float a thou one way or the other and still be ok....1/8" material....a breeze....

[Matthew Hajicek - Singularity]

 

 

And yes you can ream 60RC.

 

I presume carb reamers.

[Müřlıń®]

I presume carb reamers.

yup done it many times...use kerosene for coolant...

[Micromoldmaker]

We used to ream dowel holes under size and then lap them to size after HT.   This works well if you have a Sunnen (hole lapping machine).

[FROZEN]

Made some mold inserts out of A2. It is very stable will grow about .0002 per inch. Od grows and ID shrinks. One toolmaker I work with knew the material so well. As long as it was not a shut off. He would finish all features before heat treat. When that inserts would come back. He would shine them up with some 600 grit paper and install them.  

[dforsythe]

thank you for all of info and 1st hand experience suggestions.