Is this a safe setup for an interrupted cut on heavy part?

[boslab]

It’s about average for a 4 jaw, I’d invest in a 6 slot dogged face plate myself, they have tee slots for clamping dogs, big lathes and horizontal boring lathes use them, if irregular is a regular thing (punishing pun) a secure mounting is vital, I’ve used 8’ diameter on a craven, hell we’ve even welded tabs on before now.
taken gently it’s not unusual but it comes with increased risk, and experience is irrelevant, where risk exists accidents happen, most of the accidents happen to 45 to 55 year olds who are “ experienced “ was told expirenced people take more risk, seems reasonable
mark

[Doozer]

It seems ALL home shop guys are afraid of interrupted cuts.
The guys who do this every day don't think twice.
The only time I have had trouble with an interrupted cut is
if the steel was hard, like over 50Rc. Then it tends to get
weird.

-Doozer

[plunger]

That piece looks to be about 100mm thick. Pretty impressive if you consider its flame cut.

[mochinist]

It seems ALL home shop guys are afraid of interrupted cuts.
The guys who do this every day don't think twice.
The only time I have had trouble with an interrupted cut is
if the steel was hard, like over 50Rc. Then it tends to get
weird.

-Doozer

Yep, looks legit to me. Send it

[tom_d]

Not great, but ya' kinda gotta go with the judgment of the guy running the job. If he knows what he's doing he'll take pretty light cuts with a setup like that. A little safer change would be to add clamps over the face of the part using the t-slots in the face of the chuck. Better still with parallels bolted in under the back face using those t-slots also so the part can be clamped directly over the parallels.

Yes! +100 on the strap clamps. Put some shim spacers under the piece so the straps have something to pull against. Straps hold part against the chuck while the jaws hold part concentrically.

[Jammer Six]

Out of all these opinions, I think I'll listen to Kurtis.

[RMinMN]

Read post 16 and 17 in quick succession. Then read them again. "Most of the accidents happen to experienced machinists". "Guys who do this all the time don't think twice about it". Makes sense. I prefer to think things through before starting.

[Jammer Six]

One of my favorite sayings. I love to whip it out.

Man who says it can't be done shouldn't interrupt the man doing it.

[eKretz]

I see no problems with this work holding.

A Blanchard grinding operation for facing would be excellent if the job were dozens or hundreds of parts.

Eh, not really. He'd not likely get even more than a single dozen of those on the chuck at once. And even one part would be faster on the Blanchard than two lathe setups to face both sides at reduced feed and DOC. But most shops don't have that capability anyway.

[RMinMN]

One of my favorite sayings. I love to whip it out.

Man who says it can't be done shouldn't interrupt the man doing it.

I agree but the man who said it couldn't be done should point and laugh at the injury when the part comes out and hits him.

[Jammer Six]

The job is finished. None of the catastrophes anyone here chattered about happened.

So.

I guess Kurtis was right, and about this job, the rest of you can have a seat.

[mochinist]

I agree but the man who said it couldn't be done should point and laugh at the injury when the part comes out and hits him.

It has some heft and is only doing 40rpm. Its not flying anywhere, it will just thump out.

[mtraven]

If that bullnose center was used to center the piece, why not leave it in contact until the part was nearer to being completely faced? By the time the bullnose was in the way there would not be near the interrupted cut.

I don't know if this is right, but I wouldn't do it that way because that bull nose center is going to influence the cut. If its rigid enough to face the whole thing & do the bore without adding or removing clamping components (as was the case), all that geometry will line up better (IMO).

[eKretz]

It's really a matter of how hard you want to push the production speed. Don't really need anything if it's going to be babied, but it would probably pull out with what I'd consider heavy feed and DOC on a part and machine that size. Another factor in that equation is how good and sharp the teeth on the chuck jaws are. If they are small and sharp, and the jaws are made of good hard steel, they can hold pretty tenaciously.

[Rich Carlstedt]

Is this a safe setup for an interrupted cut on heavy part?

Simple answer, NO

Rich