1hp Bridgeport tapping capcity?

ygolohcysp · Oct 28, 2020

Hello,

I'm wondering about tapping capacity of a 1hp Bridgeport. I've done power tapping before, but I'm being asked about doing 48 tapped holes at 1 1/4-7. I have not tried anything that large, just wondering before saying I can do it.

gbent · Oct 28, 2020

You don't say material. The spindle probably has the power. The alignment key in the R8 doesn't have the drive capability. More a job for a radial arm drill.

thermite · Oct 28, 2020

ygolohcysp said:
Hello,

I'm wondering about tapping capacity of a 1hp Bridgeport. I've done power tapping before, but I'm being asked about doing 48 tapped holes at 1 1/4-7. I have not tried anything that large, just wondering before saying I can do it.

I've tapped more than a few in that general range and a tad into ignorant steel. But it was on an eight-foot American Radial DP with a skosh more power (!!!) ... and a far more suitable clutch "+ +" tap-driver .... for that sort of work.

Likely to be a tad "optimistic" even to expect to grip the tap well enough, and then.. getting even the full 1 HP TO it is not likely, either?

"Do one. Show me" Or "Fail one, trust me!" work for yah?

The 7 hoss Alzmettal AB5/s column drill here could drive those well-enough.

What else d'you have under YOUR roof ...besides a 1 HP (nominal) BirdPort?

ChipSplitter · Oct 28, 2020

Got any teenagers floating around?

ygolohcysp · Oct 28, 2020

Ahhh, sorry about the absence of material. 1 1/4" thick AR100 plate. I'm just going to accept this as a No. LOL I didn't think it would, but I had no experience trying anything in that range.

On the plus side, by the time we would need to do this job, we'll have a Mazak VTC-200 up and running (I got an answer for the time scale on this just now.)

Thank you everyone for the responses!

guest · Oct 28, 2020

Yeah, that's asking a lot of a bridgeport. You can start it with the spindle, but it's going to take 2 guys and a big-ass tap wrench to finish.

thermite · Oct 28, 2020

ygolohcysp said:
Ahhh, sorry about the absence of material. 1 1/4" thick AR100 plate. I'm just going to accept this as a No. LOL I didn't think it would, but I had no experience trying anything in that range.

I havn't had hands on a Birdport 1 HP since summer of '63, but vague recollection sez yah hit the wall at about HALF that in steel. If-even.

Even a Clausing or Powermatic column-drill has a better chance so long as.. yah have one of the top three tapping heads helping it struggle.

Decent radial, only worry is making sure stuff don't MOVE ... .bust the tap.. need burnt-out, damaged hole welded-up, start over. DAMHIKT!

But that IS another concern - this job or any other - trying to put a lot of torque through the Birdort's "flexible" structure ....even if yah had the power.

On the plus side, by the time we would need to do this job, we'll have a Mazak VTC-200 up and running (I got an answer for the time scale on this just now.)

Might do some research on "thread milling" too, then? "The time may come..." etc.

gbent · Oct 28, 2020

ygolohcysp said:
Ahhh, sorry about the absence of material. 1 1/4" thick AR100 plate. I'm just going to accept this as a No. LOL I didn't think it would, but I had no experience trying anything in that range.

On the plus side, by the time we would need to do this job, we'll have a Mazak VTC-200 up and running (I got an answer for the time scale on this just now.)

Thank you everyone for the responses!

I've never heard of AR100. Are you sure it isn't AR400? If that's the case, my answer changes to "he!! no". Thread milling on a cnc is a very good method.

ygolohcysp · Oct 28, 2020

I've just recently seen something about that. I remember both being impressed about milling the thread, and at the same time thinking "well that makes sense". LOL

I am scheduled for doing Mazak training at their headquarters in a couple weeks. I'll make sure I ask about that.

ChipSplitter · Oct 28, 2020

ygolohcysp said:
I've just recently seen something about that. I remember both being impressed about milling the thread, and at the same time thinking "well that makes sense". LOL

I am scheduled for doing Mazak training at their headquarters in a couple weeks. I'll make sure I ask about that.

Virtually any CNC mill can do thread-milling. It's just an arc that spirals up or down as it interpolates in X and Y.

It will be a winner for this application.

Like such:

G02 I0. J.25 Z.1 L3

ygolohcysp · Oct 28, 2020

I am sure on that. I can't verify that it exists, but it is definitely called out on the print.

Sorry, didn't use the quote. This was in response to asking about the AR100.

BT Fabrication · Oct 28, 2020

thats a hard no, it struggles to tap 3/4 - 10

thermite · Oct 28, 2020

BT Fabrication said:
thats a hard no, it struggles to tap 3/4 - 10

Optimist!

projectnut · Oct 28, 2020

I tried tapping a few 1 7/16-12 holes in cast iron on my 1 1/2 hp Bridgeport a few years ago and decided it was a bad idea. The machine was working harder than it ever has doing any milling work. Maybe I'm just chicken, but I decided not to destroy the machine and just do it by hand. As mentioned earlier it took 2 people and a BIG A** wrench. By the time we were finished we'd both worked up a sweat.

ygolohcysp · Oct 28, 2020

For reference, the largest I've tapped was 3/4" ACME thread, and I did that by hand. Took one person, an 8 point socket, and a breaker bar. LOL

I've threaded larger on my lathe, but that's easy. These holes are going in plate too big for lathes I have access to. I believe thread milling after getting the Mazak setup is definitely the way to go.

4GSR · Oct 28, 2020

ChipSplitter said:
Got any teenagers floating around?

Yeah, tapped my share of 1-1/4-7 holes in my young adult years while going to college. I don't know what was worse A-36 gummy plate or AR-100 plate.

Just as fast as I sent the dull taps out for resharpening, more became dull. All good old USA made taps, amazingly, we never broke one. Did wear a few out from resharpening though.

boslab · Oct 28, 2020

Single point a bush, cut hole weld in ( ok cheating)
Mark

thermite · Oct 28, 2020

boslab said:
Single point a bush, cut hole weld in ( ok cheating)
Mark

Why weld when frogs are going hungry for lack of gainful employment?

Rivit, rivit....

A "bush" is meant to be "single-pointed"....., even if Bikini-waxed.

CarbideBob · Oct 28, 2020

No, ....,,,,,

CalG · Oct 28, 2020

Check out the "spec" on drilling capacity under power feed from the BP owners manual. IIRC it 1/4 inch.

Use the BP for alignment, but crank the tap around with a suitable handle. It won't take long, the material is not thick, BUT it is TOUGH!

Back off, break those chips!

1hp Bridgeport tapping capcity?

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