Turning A105 Steel

First time turning this material. Asked up and down our lathe line, no one really had any experience with it. Company down the road dropped this on us since we have a lathe with large boring capabilities. Looking for any information anyone could throw at me to give me a general idea how to go about this speed/feed wise and anything uncommon I could run into.

Info: Piece is 30in long by 6in OD. Need to bore a 17 7/8 bore in length at 3in 5/8 OD with a 63 finish at one end and a 12 1/8 5degree taper bore starting at an OD of 3in 5/8 with a 63 finish at the other. I have an Ultradex chatter free boring bar at 1 1/2 in diameter by 19in length with a DCMT insert, a 1 1/2 diameter by 16in length Kennemetal chatter free bar with a CNMG insert and a Sandvik Silent Boring Bar 1 3/4 diameter by 24in length with a CNMG insert, all with a .015 radius tool tip. Holding the bars the only option I have is a tool post holder with boring tool block holders. We were looking into building an A Frame mount for the Sandvik bar, but havent sold the foreman on it just yet. Holding the piece will be a 3 jaw manual scroll chuck with soft jaws and two steady rests. One positioned in the middle of the part and the 2nd towards the end of which will be bored. If there is any other information I could provide please ask and Ill try to supply it.

Be interesting to hear how this goes!

That mount sounds like your weak spot to me....


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Think Snow Eh!
Ox

Similar to 1140 or a supercharged 8620. Should turn nicely.

ASTM A105, Carbon Steel Forgings for Piping and fittings | Sunny Steel Enterprise Ltd.

There seems to be some vagueness in the ASTM spec as to use of hot rolled or forged material in various applications.

Didnt get a chance to make any real chips today. Had to wait on a new set of soft jaws and a sleeve for the boring bar. By the time I got everything set up and ready to go it was time to leave. The smaller steady rests we had were too small, so I switched to a U style steady rest. The company that handed the job over turned the OD and opened up one end leaving about 1/2 of material left to machine. Here's a picture of what I got so far.

Will that steady run smooth enough to provide a 63?


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Think Snow Eh!
Ox

Believe it or not, it actually works rather well. I had someone else ask me the same question so I have a few pictures of a spindle I machined. I know its just a picture and you cant really tell from one, but it gives you a good idea.

That is a very interesting steady. I don't recall ever seeing something like that. Who makes it?

alphonso said:

That is a very interesting steady. I don't recall ever seeing something like that. Who makes it?

Click to expand...

As far as I am aware, it came in a package deal with the lathe, which is a Romi M27. It came with two smaller sized steady rests, and then the one you see pictured.

So after messing with various speeds/feeds/DOC I landed this finish, which appears to be just about a 63. Which Im ok with. Do I wish it was better? Of course, but after almost 2 wasted days and 7 more pieces left, Ill settle for this. Had some trouble right out of the gate with vibration, not from the boring bar, but from the surface finish on the OD. The company that handed these pieces had turned to OD to finished dimensions, which is fine, whatever. Only problem was, the surface finish they left was picking up in the wheels of the steady rest causing vibration. So after being granted permission from the company to turn a section for the rollers, the vibration problem was minimized. As for the Sandvik Silent Boring Bar, best tool Ive used to date. Didnt even know it was cutting till I seen the chips being flushed out. Anyway, thanks to anyone took the time to read this.