Ideas for threading highly abrasive material

[Guess_who]

We are trying to tap 6-32 STI thread in aluminum with a 25% silicon content. Tried Taps, thread hobs, thread mills with multiple coating, and rolling. Nothing last longer than a few holes. and we need to chase every hole by hand. 

PCD works for milling, but it's difficult to find PCD thread hobs.

Any ideas would be appreciated. 

[Matthew Hajicek - Singularity]

EDM...?

There are carbide taps available, don't know if they're any good:

https://www.allenbenjamin.com/products/carbide-taps

How many holes do you need to do?

[Guess_who]

We are trying carbide. Not really the long term answer. We have a few hundred parts and maybe 8 holes per part of various sizes.  

[Matthew Hajicek - Singularity]

Any chance of getting better material for the next run?

[YoDoug®]

Harvey tool makes single tooth threadmills with amorphous diamond coatings for composites and other abrasive materials. 

[Guess_who]

15 hours ago, Matthew Hajicek™ - Conventus said:

Any chance of getting better material for the next run?

The material is a special aluminum mixed with 25% silicon. 

 

51 minutes ago, YoDoug® said:

Harvey tool makes single tooth threadmills with amorphous diamond coatings for composites and other abrasive materials. 

That is what we are trying right now with some success. After the second or third hole, we need to start chasing with a hand tap. One hand tap lasts for about 2 holes. 

 

Maybe this is just what we have to deal with. I was hoping there were some special tools that I don't know about. PCD seems to work best but can't find anything for 6-32 sti in PCD, only diamond coated. 

 

[YoDoug®]

18 minutes ago, Guess_who said:

The material is a special aluminum mixed with 25% silicon. 

 

That is what we are trying right now with some success. After the second or third hole, we need to start chasing with a hand tap. One hand tap lasts for about 2 holes. 

 

Maybe this is just what we have to deal with. I was hoping there were some special tools that I don't know about. PCD seems to work best but can't find anything for 6-32 sti in PCD, only diamond coated. 

 

If it is a repeat job you could probably get a tool mfg to do special coatings. When I worked in OK we used Evershap Tool in Tulsa. We had them do a lot of custom coatings for testing. From what I have seen, PVD works well on high silicon aluminum. 

[Guess_who]

59 minutes ago, YoDoug® said:

If it is a repeat job you could probably get a tool mfg to do special coatings. When I worked in OK we used Evershap Tool in Tulsa. We had them do a lot of custom coatings for testing. From what I have seen, PVD works well on high silicon aluminum. 

We'll look into PVD. Thanks

 

 

[jeff]

23 hours ago, Guess_who said:

 

PCD works for milling, but it's difficult to find PCD thread hobs.

Any ideas would be appreciated. 

Ask your cutting tool resharp guys, ours will send out any tool to get diamond coated and it's actually not that pricey.

Granted it's not a true PCD,but we have great success using these diamond coated tools in G10.