Hi gang,
I'm trying to tap deep holes in aluminium. It's a for a pallet project - picture below. I need 33 tapped holes 1/4-20 in each pallet 1.2" deep through holes. so 4x 5x deep. I've busted two taps so far. I'm pretty sure I busted the taps by trying to tap too deep and the shoulder of the tap is hitting the material.
I'm using a spiral flute tap - which pulls chips out like a drill - in theory - seems like it just packs the chips into the flutes instead. It's a Chinese HSS tap from KBC. Nothing too fancy. It's all I have on hand here. A gun tap or spiral tip tap which pushes the chips forward through and out the bottom might be better. I'm trying to tap the holes under power in a single operation, 500 RPM. It's a CNC mill so the mill has to feed and spin at the right rate according to thread pitch. The mill supports this but I don't think there is anyway to "peck" or spin/tap forward, spin back out a turn, tap forward during the cycle like you would with a hand tap. I'm using coolant as lubricant (it's 90%water, 10% coolant oil). Trying it by hand with the tap handle shown it gets pretty hard to turn about 0.8" down into the hold. The flutes end up pretty packed with chips when I spin out the tap.
It's mystery aluminium - I think it's likely 6061. No problems milling, facing, or drilling, behaves as you expect I think.
A few q's, can I expect a power tap cycle 1" in a single continuous tap cycle to work? This used to work on my manual/cnc hybrid mill without too much trouble.
Do I actually need a reduced shank tap to do this operation?
Should I be using a roll tap instead?
Is coolant inadequate and I need to brush on A9 aluminium specific coolant for each tap cycle?
Do I need expensive ie good taps? I tend to bust 1/4" taps so I'm reluctant to buy.
Do I need a floating head tap holder realistically?
J
I'm trying to tap deep holes in aluminium. It's a for a pallet project - picture below. I need 33 tapped holes 1/4-20 in each pallet 1.2" deep through holes. so 4x 5x deep. I've busted two taps so far. I'm pretty sure I busted the taps by trying to tap too deep and the shoulder of the tap is hitting the material.
I'm using a spiral flute tap - which pulls chips out like a drill - in theory - seems like it just packs the chips into the flutes instead. It's a Chinese HSS tap from KBC. Nothing too fancy. It's all I have on hand here. A gun tap or spiral tip tap which pushes the chips forward through and out the bottom might be better. I'm trying to tap the holes under power in a single operation, 500 RPM. It's a CNC mill so the mill has to feed and spin at the right rate according to thread pitch. The mill supports this but I don't think there is anyway to "peck" or spin/tap forward, spin back out a turn, tap forward during the cycle like you would with a hand tap. I'm using coolant as lubricant (it's 90%water, 10% coolant oil). Trying it by hand with the tap handle shown it gets pretty hard to turn about 0.8" down into the hold. The flutes end up pretty packed with chips when I spin out the tap.
It's mystery aluminium - I think it's likely 6061. No problems milling, facing, or drilling, behaves as you expect I think.
A few q's, can I expect a power tap cycle 1" in a single continuous tap cycle to work? This used to work on my manual/cnc hybrid mill without too much trouble.
Do I actually need a reduced shank tap to do this operation?
Should I be using a roll tap instead?
Is coolant inadequate and I need to brush on A9 aluminium specific coolant for each tap cycle?
Do I need expensive ie good taps? I tend to bust 1/4" taps so I'm reluctant to buy.
Do I need a floating head tap holder realistically?
J
