I need some help and suggestions for tapping sa106 carbon steel

[Ironman326]

Hello I'm doing a 500pc job flip flop part. Right now using G32 cycle tapping 2.75 through. These parts have been swedged down to be tie rods. Company keeps wanting to use cheap cutting taps. Material designation says it's more favorable to forming but they either cant be formed per consumer spec or they just won't try to form threads. Spiral flute 5/8-11 RH is what we are using now. No coating. Boss says coated tap that will not crash machine is not available. We are not getting more than 40 or 50 holes before tap failure or thread finish being unacceptable. Running at 305 rpm with flood coolant at 14 concentration. Have also tried MOLY D and extra thick tap magic. Any help would be greatly appreciated.

 

[Limy Sami]

Nothing like making life hard for yourself is there? ......but you are where you are.

So in your shoes I'd at least halve my cutting speed - say 150 rpm, use the best cutting oil you can, ..............and back out half way though for more oil.

Don't forget the dip can trick.

 

[jim rozen]

How do the taps fail? Do they blow up in use?

Spiral taps eject the chips out the top of the hole but I've found they are a bit weak and will shatter if loaded hard.

1) be sure the swaged end ID is controlled to be not undersized.

2) try two flute gun taps.

 

[Ironman326]

They are exploding when trying to peck tap. Used oil and coolant. Running at slower rpm is causing more tearing and ripping of the thread. We are drilling the ends to size and they are going over about .004 so a 17/32 hole is ending up around .535. Best results have came at the higher rpm going to full depth and retracting. No peck.

 

[Milland]

Sounds like there's a synchronization error if the taps are breaking with pecking. Presume you're rigid tapping, no extension/compression adapter?

Also, spiral flute to try to keep chips out of the center of the tube? Gun taps would certainly be my go-to otherwise.

And back to thread forming - it really seems like you should try a couple test parts, you'd get a stronger thread and no chips - a win-win. But you might have to go to a reamed hole to control the geometry correctly. Sometimes you just have to tell the bosses there's too much cost to NOT doing it right...

 

[Ironman326]

That's why I'm here! To get more info. I am using a compression holder. Yeah the spiral flute is to keep chips out of the part. If not they pack into the tube and then it's 5 minutes a part just digging chips out. I have suggested that the hole be bored to keep it in center line. Even boring a half inch deep for lead in there is still a wobble to the drill at the bottom of the hole. It's a small bore but with a 3/8 carbide boring bar i figure it's doable. 5 taps already down the drain. Everything is on center line and parallel as far as spindle and they turret. Going to again suggest boring the hole tomorrow

 

[Milland]

Presuming this is on a CNC lathe. Perhaps drill, then ream the last ~.03" with a short carbide reamer. If held in a rigid adapter block/collet, it should handle a little eccentricity from the drill, especially if you feed the first ~.1" slow to allow it to "bore" a little.

Presuming the drilled chips are mostly evacuated by the flutes? Some must get into the tube anyway, yes/no? Certainly when boring or reaming some will be pushed in, but you can get RHH reamers, you'll just pay more than for straight flutes.

 

[Ironman326]

Yes this is on CNC. No chips are getting into the part from the drill process. The taps fail in the part due to the chips from tapping are wrapping around the tap and causing them to fail. I've had taps coming out of the hole break when the chips wrapped around the tap. It's almost impossible for me to get them to change the process because they think this will work doing the same thing as caused the taps to break.

 

[Limy Sami]

Time to find another job.

 

[cyanidekid]

wait.. "boss says coated tap that will not crash machine is not available" ????

lets look at that, is that for real? most any high performance tap is available coated, so this is a giant red flag to my ear.

do you have a tooling vendor who really knows what they are talking about ( I know, maybe a tall order haha!) that can come in and provide an outside opinion?

 

[Ironman326]

We don't have a tool rep that knows anything. The boss wants to save a dime and it cost him a dollar. I did fix my problem by boring the hole to make it true. Not a problem since. My boss is stuck in the old ways of machining. Business manager wants to go modern but the money man won't come off money for better tools. I've tried to explain the benefits of high quality tools but they don't want to budge. Oh well. They told me boring the hole would make no differences. Well I proved them wrong on that one yet Again

 

[Milland]

I really think you should look for a better job where the owners have a clue.

 

[Brett W]

Or at least respect your input and experience. Want to move to Huntsville and make race car parts? HAHA

 

[Mtndew]

I really think you should look for a better job where the owners have a clue.

I agree. It sounds like a dead-end job.
If the company cannot see ROI value in better tooling/machines and just sees the initial price tag,then they won't ever change or grow.
Time to GTFO.

 

[BT Fabrication]

Spiral fluted tap?

 

[Milland]

Spiral fluted tap?

That's what he's using, says so in the OP.

 

[Ironman326]

I am considering that job change idea. It's definitely not a place that will grow a lot under this owner. But he's got one foot out the door anyway so I'm trying to hang around and possibly move into a better position and pay rate when the old head moves on. They do value my suggestions and input. But not until I prove to them it will work better than the crazy crap they are asking for me to do. No joke.........the owner wrote me a program once that attempted to use a flat bottom spade drill as boring tool. Told my super and the owner numerous times it wouldn't work. Until I showed them it wouldn't they insisted it would.

 

[Ironman326]

I wouldn't have to move. Hsv is only 40 minutes from home. This job is 35

 

[Ironman326]

After Boring the hole. I've now made 75 parts in less than 4 hours. 150 holes. Yesterday in 9 hours we managed to get 60 and break 3 taps fooling around with all the boss man's bs

 

[Milland]

Good stuff.

Let us know if you take that other job...