Help reaming Iconel 718

[toolsharpener]

I hear HSS works better than carbide on iconel. Is this true, what rates would you run a reamer for HSS and carbide.
Any help would be great!

Jeff

[Boots]

You heard right Jeff HSS works better than carbide on that material. But I have never reamed it before so I can't give you speed and feed info plus you didn't state your hole size and the type of reamer you are trying to use. That matters on calculating speed and feed. I would try a HSS reamer and make it a floating reamer so it just reams and follows the hole and does not bore it to irregular shape. It's difficult to get a reamer spinning true in a holder of any type, collet or rigid.

[christinandavid]

Hi,

Only have experience with HSCO Reamers (cheap and cheerful), but I would apply exactly the same approach with carbide. Leave as much material as you dare in the hole for the reamer to take out or it will not last. Run it dead slow. In my experience (5mm-30mm holes) I would run 200-80rpm respectively, 100rpm x 16mm/m feed being about the average. This approach is the result of having to ream a shed load of holes with a limited amount of tooling.

If possible slot drill/circular pocket the first 1-2mm at the top of the hole about 0.05mm under finish hole size to guide the reamer in on position. Use copious amount of coolant/cutting fluid, whichever is most practical.

As soon as your reamer gets worn on the lead chamfer it will start to cut erratically ie big, small, tapered, crap finish. At this point chop the end off and regrind lead chamfer. You can even do this by hand if you have a nice pedestal diamond lap available (with adjusting table/v-block attachment). This has to be extremely accurate to cut size again so do a few test holes in comparable material until you're confident.

Under no circumstances stone the reamer down/burr the reamer up to achieve size as it will probably only be good for one hole. You also need to keep the piloting tools in good condition to prevent reaming a work-hardened hole.

DP