M24 threads with a Mag drill?

[NRDock]

SO, somebody somewhere decided to skip a lot of tapped holes in the fab shop and send bare flat mild steel plates to the field. The site has acknowledged they have Mag drills and can drill the holes. They are putting up a fuss about tapping the M24 threads. Is this really a problem? I quickly found tooling claiming this capability in the internet, but this seemed to be at the upper limit.

 

[DDoug]

SO, somebody somewhere decided to skip a lot of tapped holes in the fab shop and send bare flat mild steel plates to the field. The site has acknowledged they have Mag drills and can drill the holes. They are putting up a fuss about tapping the M24 threads. Is this really a problem? I quickly found tooling claiming this capability in the internet, but this seemed to be at the upper limit.

What kind of "Mag Drill".
The newer ones use cutters to make bigger holes with smaller/lighter motors, but can't tap much.
I have an old B&D with a 2-speed gear box that would probably tap that, but it's upwards of 85 lbs.

 

[NRDock]

I don't know what they already have on the other side of the world. My main concern is that they can buy tools which they can use to drill and tap a couple hundred M24 holes in 75 mm think plate.

 

[Peter from Holland]

I did M16 holes with a impact hammer Worked flawlessly

Peter

 

[DDoug]

I don't know what they already have on the other side of the world. My main concern is that they can buy tools which they can use to drill and tap a couple hundred M24 holes in 75 mm think plate.

Don't you just love designing and then throwing it over the fence ?
I hate trying to guess what capability a shop has so far away, and I never get any feedback unless it was a fail.
I am concerned that there might be a VooDoo doll of me in a shop in India somewhere.....

 

[dalmatiangirl61]

I don't know what they already have on the other side of the world. My main concern is that they can buy tools which they can use to drill and tap a couple hundred M24 holes in 75 mm think plate.

Not all mag drills have reverse, so that might be part of the problem, then add in that its a couple hundred

 

[Joe Gwinn]

SO, somebody somewhere decided to skip a lot of tapped holes in the fab shop and send bare flat mild steel plates to the field. The site has acknowledged they have Mag drills and can drill the holes. They are putting up a fuss about tapping the M24 threads. Is this really a problem? I quickly found tooling claiming this capability in the internet, but this seemed to be at the upper limit.

Isn't this the fab shop's problem?

 

[Strostkovy]

Looks like the fab shop has a rejected batch of parts to fix. Options are to fix it onsite, pay for a contractor to fix it, or pay to have it sent back for rework.
If you think you can tap all of the holes with a mag drill then you can pack one up in a suitcase and fly out there to take care of it.

 

[NRDock]

Isn't this the fab shop's problem?

Complicated contract. We design. Customer procures non proprietary stuff. Apparently the customer accepted it this way. Now the erectors want an easy way forward. Not exactly my problem, but we still have an interest in helping things go as well as possible.

 

[Strostkovy]

It's been a long time since I saw it but I have seen a single point threader that uses essentially a boring bar and a guide bushing for alignment for field threading large holes.

 

[4GSR]

Get several boxes of good old USA brand taps and drills, box up and send to them. Let them figure the rest out.
Edit: I have tapped lots of 1"-8 threads in gummy A-36 plate many years ago with a POS B & D mag base drill. No fun at all!!!

 

[FamilyTradition]

If they can get their hands on a pipe drilling/tapping machine and adapt it to run on flat plate it might make this job a bit easier. Seems to work good for drilling and tapping lots of holes in water mains.

 

[DDoug]

I think you can rent something more "industrial" IIRC Lamina makes a hydraulic drive machine.

 

[memphisjed]

mag drill hole, use impact for tapping hole. Versa-drive from hmt is a good choice.

 

[Bill D]

Maybe get some custom taps made in three or four undersizes. Can the bare hole be enlarged for less percentage engagement.
Bill D

 

[john.k]

Run of the mill job ..........until the OP casually mentions 75mm thick plate.........jobs Ive been on would ship the plate back to the shop for completion.

 

[LKeithR]

I have an old B&D with a 2-speed gear box that would probably tap that, but it's upwards of 85 lbs.

I've got the same beast. I've tapped smaller holes with it OK but M24 is getting up there in
size. Biggest problem would be just holding the tap without it spinning. Not gonna do that
with a regular drill chuck.

If the parts have to go back to the fab shop how are "they" going to tap he holes? We haven't
been told how big the plates are. Too big and they won't fit in a mill or drill, then the shop would
have to resort to some kind of portable machine; probably hydraulic. If that's the case wouldn't
it would be cheaper to ship the machine to the job site rather than return all the plates?

 

[Overland]

Depending where they are, labor might be quite inexpensive.
Couple of guys with a big tap wrench.......

 

[Strostkovy]

Maybe get some custom taps made in three or four undersizes. Can the bare hole be enlarged for less percentage engagement.
Bill D

I've been wondering about taps that are essentially a two start thread at double the pitch, that then merge into a single thread over the length of the tap. That seems to me like it would take the least amount of torque.

I may have to draw up a rough profile for that to make any sense

 

[RC Mech]

Milwaukee model 1410 or something along those lines, I just leafed through the manual and the max tapping capacity in “steel” is 1” - 14.

This is the mag drill with a #3 MT spindle. I’d say it weighs every bit of 75 lbs. I donno if’n I’d trust a tap like that to not spin, but find an old Morse taper tap holder?