Bridgeport Interact 2 tapping capacity

With the 2-3 HP motor, variable pitch drive and back gear, I'd expect you have available torque for tapping far larger than anything you're likely to want to do. The Interact may not have been designed for rigid tapping, but it was expected to be used with tapping heads, and I don't think the torque requirements are any different for those.

Say, would 3/4" NC be an issue? This is the biggest thread I had to tap to date.

I would think 3/4" would be fine in normal materials. I think your gears are probably not the weak link, and your vari-belt drive would likely slip before you could damage the gears. This does bring up the question of whether you have wired your VFD alarm output into your E-stop circuit so the mill will E-stop if the VFD trips on overload, etc. vs. trying to push a non-rotating end mill through the material and eventually tripping on a following error.

I would suspect that in back gear you could handle 1/2" threads. Anything larger, I would look into thread milling anyway -- less stress on the machine, and more thread pitches possible with a single cut thread mill. Of course, with a multi-cut one, you could mill the thread in a single pass around the hole, but the mill would be good only for a single specific pitch.

Good luck, DoN.

Ive tapped 1 1/4-8 on the Gorton with no issues in low gear. Just chugged right along.

One of these days Ill take out a big tap and see how big I can go.

Btw..the Gorton spindle is 3hp.

Gunner

I am the Sword of my Family and the Shield of my Nation. If sent, I will crush everything you have built, burn everything you love, and kill every one of you. (Hebrew quote)

Piece of cake. Lube well, drill the proper pilot hole, dump it into low gear and voila!

Gunner

I am the Sword of my Family and the Shield of my Nation. If sent, I will crush everything you have built, burn everything you love, and kill every one of you. (Hebrew quote)

For me, the weak link is holding the tap. I just bought another 1" NPT on ebay. The last one spun in the TG100 collet holder with bad results. I do all tapping in back gear on my excello knee mill.

karl

Ayup. I do everything over 5/8ths in holders. Ive had Stuff move in my collets. My Gorton is NMTB 30 but Ive got a set of collets up to 7/8ths. And a nearly full set of tool holders.

Ive not tried the Abene yet for tapping. Its got a 4hp motor and a very good gearbox..I can drop down to 28 rpm..which should provide a SHITLOAD of torque.

Gunner

I am the Sword of my Family and the Shield of my Nation. If sent, I will crush everything you have built, burn everything you love, and kill every one of you. (Hebrew quote)