BSP tap needed

I need to make a single threaded hole, 1/4"bsp into the side of a 1 1/4" BSP iron pipe.

As this may be the first and last time I will probably need to tap a 1/4" bsp hole will a single taper tap do?

Edited By pgrbff on 14/04/2021 15:06:52

I should think so, if not just grind the end off a little.

regards Martin

Yes if you can get through far enough to get the full thread

If you an get one buy a second tap, a little less taper lead than a taper tap.

Have you considered going as far as you can with a taper tap and then grinding away the taper sufficiently to use what's left to create the full thread?

As a woodworker I don't often need taps. I want to make up a mixing valve for my sandblaster and need to tap a 1/4" BSP hole in the side of a 1 1/4" iron tube. I'd prefer to buy only one tap and I'm not sure which would be the best choice. Are BSP threads always tapered?

No, there are tapered & none tapered. This has been covered before somewhere on here.

Steve.

Where are you based, I have a selection of BSP taps.

Robert Butler

You could make a flat on the pipe, weld on a suitable fitting and drill through?

Hi Steve. Have you thought of using a T joint. 1 1/4 x 1 1/4 x 1/4 My local pipe suplier will thread the 1 1/4 pipe for very little whilst I wait and not a lot of money. You will get a better seal as a pipe is not that thick pipe section and not many threads.

David

You need to look at the fitting you want to screw into the tapped hole. If the male thread on the fitting is tapered, you will need BSPT tap. (T for tapered.) Most ordinary black or galv pipe fittings will be the tapered thread, put together with thread tape or sealant.

If it is not an arduous duty, make a flat as use a parallel thread plus a sealing washer?

Thanks but I'm in Italy. At least I can find BSP taps here, German seem to be reasonably priced. Normally I buy used English manufactured from Ebay when I other than metric.

I'm trying to keep the airflow in the 1 1/4 pipe as smoth as possible. I need to tap a small valve into the pipe to allow air in, and be able to adjust how much air, to hopefully create a venturi effect to open up glass beads flowing through the pipe.

Hi is this for some type of sand/glass bead blasting machine. If it is, I have made one in the past and I would have thought that adding air into an already pressurised pipe would have been counteractive to the flow and venturi effect further back down the pipe, perhaps slowing down suction on venturi. The biggest problem I had was moisture in the media/air and clogging after a while of not using it clearing set beads.

David