Need some help with a good starting point for Rigid Tapping RPM on Aluminum

I don't do a lot of rigid tapping on my Haas DM-2, But I do some, and I am looking for some guidelines.

1/4 - 20 threads

6061 Aluminum stock is 1/2 thick

Hole is al the way through the stock.

Questions:

Recommended RPM ?

Should I use peck, or do it all in one pass ?

I'm currently tapping at 600 RPM, and I know this is probably way to slow..... so I figured I would see what other people are doing.

Thanks....

Kent

We use roll form taps in aluminum. That's only 2x dia., so all the way through in one pass. 600 RPM seems about right. Follow the manufactures guidelines for surface speed/RPM. Lots of flood coolant.

We normally get thousands of holes out of a tap.

Some factors to take in account:
1. Recommended cutting speed for the workpiece material.
2. Recommended cutting speed for the tap.
3. machine capability ( is there enough torque at selected rpm )
4. Local conditions. We use a special tapping oil. Saves the tool. Makes the cut perfect clean and ensures accuracy. It's expensive and requires manual intervention - must be applied manually for each hole. There are some ( aluminum, copper ) alloys impossible to tap without this oil.

Quote:

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Originally Posted by kentdesautel13

I don't do a lot of rigid tapping on my Haas DM-2, But I do some, and I am looking for some guidelines.

1/4 - 20 threads

6061 Aluminum stock is 1/2 thick

Hole is al the way through the stock.

Questions:

Recommended RPM ?

Should I use peck, or do it all in one pass ?

I'm currently tapping at 600 RPM, and I know this is probably way to slow..... so I figured I would see what other people are doing.

Thanks....

Kent

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Nothing below 800RPM for 1/4-20 1000RPM to 2000 RPM would be the norm, your machine could run this up to 5000 RPM

Open hole 2000RPM with flood coolant

Quote:

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Originally Posted by mactec54

Nothing below 800RPM for 1/4-20 1000RPM to 2000 RPM would be the norm, your machine could run this up to 5000 RPM

Open hole 2000RPM with flood coolant

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Thank You.... this info will get me on the right track....

Thanks again for the quick response.

Kent

Thank You Jim....