threading 304 ss

klemchuk · Mar 18, 2018

HI all;

Looking for advice on either tapping or single point in lathe 1" dia x 8 tip through 1" block.
I have a 3hp bridgeport clone and 14 40 engine lathe.
This apparently will be an ongoing project for my customer.

Thanks!

howieranger · Mar 18, 2018

I make shooting rests that use a 1 by 8 tip thread for the central screw. I just drill the proper size and run a tap through the captains wheel blank in both mild steel and aluminum. 80 rpm with no problem. I have never tried it in 304 though.

Lakeside53 · Mar 18, 2018

You are going to need big arms to hand tap 304 at 1-8, and I wouldn't want do it under power on a BP.

Single pointing will also have it's challenges. Razor sharp tooling or new lay-down inserts, keep up the DOC. 304 likes to work harden if you aren't cutting optimally. Use a good cutting oil.

litlerob1 · Mar 18, 2018

Engine Lathe, use the Tailstock, a big crescent wrench against the Carriage.

Get everything in place, triple check spindle speed LOOOOW, tailstock in the back of the Tap, wrench on the tap and against the Carriage, hand on the Tailstock's Quill crank, OIL!!! Go, Stop, Reverse.

R

guest · Mar 18, 2018

^^^ And repeat "Oh Please God, Oh Please God, Oh Please God..."

Think tapping it might be the easy part, lol.

litlerob1 · Mar 18, 2018

guest said:
^^^ And repeat "Oh Please God, Oh Please God, Oh Please God..."

Think tapping it might be the easy part, lol.

And, I forgot the most important thing there......don't let anyone see you doing that, especially some greenhorn.

Hide your Hacksaw too.

R

Gordon Heaton · Mar 18, 2018

I cut a lot of external threads in 304 using coated carbide partial profile inserts. I cut it just like anything else, never a problem with work hardening and the final cuts are typically in the .001 range. If I use a die at all it is just for cleanup after doing most of the work with the lathe. I've not had great results using a die only. Same results would be expected on internal threads.

There is more than one variety of 304 though. We use 304L

Luke Rickert · Mar 19, 2018

Do both, single point close to final size and then clean it up with a tap. Works great for things like acme nuts.

Limy Sami · Mar 19, 2018

klemchuk said:
HI all;

Looking for advice on either tapping or single point in lathe 1" dia x 8 tip through 1" block.
I have a 3hp bridgeport clone and 14 40 engine lathe.
This apparently will be an ongoing project for my customer.

Thanks!

IMO - No way in a BP, ..nor tapping from solid in a lathe, .... 1''x 8 takes some bloody winding in ''mild steel'' and 304 is many times worse! .......I'm in the screwcut in the lathe and if need be, final size with a tap, camp.

FWIW - You don't state the % of thread depth required, ..were I in your shoes, with any say in the matter, I would make it as low as possible.

Red James · Mar 19, 2018

Since this is a repeating job talk to a cnc shop. Find out how many pieces they need to get a reasonable price on thread milling these parts.

VictorStagnetty · Oct 4, 2019

Thread mill is the way to go.

steve-l · Oct 4, 2019

VictorStagnetty said:
Thread mill is the way to go.

How do you thread mill on a Bridgeport?

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threading 304 ss

klemchuk

Aluminum

howieranger

Aluminum

Lakeside53

Stainless

litlerob1

Diamond

guest

Guest

litlerob1

Diamond

Gordon Heaton

Titanium

Luke Rickert

Hot Rolled

Limy Sami

Diamond

Red James

Stainless

VictorStagnetty

Plastic

steve-l

Titanium

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