Dimpling tool for a 1/2” hole

[ISUBrew79]

Does anyone have an idea what I might use to create a dimple for silver soldering a 1/2” Tri Clamp ferrule with 1/2” OD tube into the wall of a brew vessel? I️ figure I’ll drill a 3/8 hole and use something as a die to create a dimple to widen the opening to 1/2”. I️ just don’t know what to use as a die. I️ haven’t been able to find a correctly sized reducing pipe fitting.

Maybe I️ will have to take a piece of 1/2” OD stainless tube and taper the end with a grinder?

 

[don_bran321]

https://www.brewhardware.com/product_p/ptbulkhead_tool.htm

 

[ISUBrew79]

https://www.brewhardware.com/product_p/ptbulkhead_tool.htm

That is the concept, but about two times too big. The fitting I plan to solder in is about half the diameter of a 1/2” NPT coupler.

 

[ancientmariner52]

Do you have a socket set handy? Might get lucky and find the diameters you need. If so use a nut, bolt, and washers to make a dimpling tool as in Bobby M's video.

 

[BeardedBrews]

Maybe I️ will have to take a piece of 1/2” OD stainless tube and taper the end with a grinder?

Tapering a throw-away is the approach I've seen most others use, especially before the pull-through fittings were readily available. Someone on here put their spare piece in a drill press so they could rotate and angle-grind at the same time, the results looked pretty clean.

 

[BeardedBrews]

Do you have a socket set handy? Might get lucky and find the diameters you need. If so use a nut, bolt, and washers to make a dimpling tool as in Bobby M's video.

If you got lucky on a socket that'd be the easiest approach. Many of the impact sockets have a nice straight taper on them
https://www.grainger.com/product/1AW51

 

[jimmayhugh]

I've used sanitary weld reducers to dimple my 1", 1.5" and 2" TC clamps, but it doesn't look like anything is available for the size you want.

 

[processhead]

Tapered drift punches are readily available in many sizes.

Its a ready to use solution for dimpling.
Drill your initial undersized hole. Then tap the punch in to create the dimple. Monitor the hole diameter carefully so you don't overshoot the desired diameter.

 

[ISUBrew79]

Tapered drift punches are readily available in many sizes.

Its a ready to use solution for dimpling.
Drill your initial undersized hole. Then tap the punch in to create the dimple. Monitor the hole diameter carefully so you don't overshoot the desired diameter.

View attachment 549411

That’s a very good suggestion. I will look for a suitable punch and give that a go next time.

I was able to create a makeshift dimpling tool by tapering a piece of 1/2” OD, 0.0625” wall stainless tube with a grinding wheel on my Dremel. I had to spin the tube by hand to try to keep it even. I’m sure it would have worked better if I had a 1/2” drive drill that I could have secured the workpiece into.

 

[aufgehdraht]

same concept but a ring mandrel