Looking for a "best way"...

[swampsavage]

I have some 7/8" brass square stock that needs to be round. Just getting started with this machining hobby and have read that lathe turning it directly may not be the way to go. That the interrupted cutting action might put a strain on things. Besides the 7X16 500W lathe w/5" 4-jaw I have the SX2 500W Mill. Also have mill vice, hold downs, fly cutters, end mills and willing to get a rotary table w/4-jaw, dividing plate and tailstock if it could be part of the solution (plan to get it eventually anyhow).

Welcome any suggestions and Merry Christmas!

 

[Jasonb]

As its brass I don't see it being an issue just make sure you have a sharp tool with little or no top rake, if there is a reasonable length that needs turning then tailstock support will keep it all rigid.

Jason

 

[Mainer]

The way I'd probably do it is buy some 7/8" round brass rod.

But if only part of the square bar needs to be round, or you definitely want to use the square bar, I'd just do it in the lathe. Interrupted cut isn't that big a deal, especially in something like brass. Use a good sharp toolbit, take small initial cuts until the bar rounds off a little, and watch out for chips - they will fly everywhere.

 

[Philjoe5]

Hello SS,
I am fairly new at this hobby and when I began I heard lots of horror stories about doing interrupted cuts. In practice, with a set up as rigid as you can achieve, a good HSS toolbit especially for steel, slower rpms and careful feed rates it isn't that difficult to achieve good results. Though carbide toolbits are prone to shatter on interrupted cuts I have never had this happen with the brazed tip variety but again I cut pretty conservatively.

Try going with light cuts and slow hand feeds to get a feel for how rigid your set up is. You shouldn't get chatter or excessive vibration especially with brass. If a few passes of the toolbit seems to be going well then go to autofeed, but go slowly until most of the interruption is gone from the cut.

Hope this helps,

Cheers,
Phil

 

[jonesie]

cutting that on the lathe should not be a problem , just make sure the tool is on center, and using carbide should not be a problem if is not dull or chipped. go easy till you have some of the corners rounded off , good luck jonesie

 

[swampsavage]

Thanks everyone. I guess I'll just go with the lathe and 4-jaw. The stock is 14" long but I'll only be turning about 6" of it. I have some HSS toolbits I haven't profiled yet so will dedicate the 1st one to brass.

 

[Troutsqueezer]

Interrupted cuts are part of the game. You wouldn't get much done if you avoided them. I'm with Jason Mainer, you would be turning a good percentage of that square stock into swarf to get it round. Square stock gets used a lot in this hobby so you will likely be needing it before long. It would more cost-effective to buy some rod and keep the bar for other things.

 

[prof65]

If you don't feel confident with interrupted cut, you can round the corners with a file or a belt sander, then use the lathe to complete the job.

 

[swampsavage]

Interrupted cuts are part of the game. You wouldn't get much done if you avoided them. I'm with Jason, you would be turning a good percentage of that square stock into swarf to get it round. Square stock gets used a lot in this hobby so you will likely be needing it before long. It would more cost-effective to buy some rod and keep the bar for other things.

Got 4 pieces of 7/8" square 14" long and only need 1 piece rounded for about 6". I will keep the rest for future use and not into buying brass just yet. Will keep the swarf in a ziploc for future scrap if the price keeps rising

...history of the brass acquisition. Before wedding my spouse she was seeing a tool and die maker...he made her a coffee table with the 7/8" brass for legs...bored 1/2" in one end and steel 1/2" rod pressed in 1/4" steel plates for attachment to the hardwood top...never had the rod welded so loosened over the years and we don't need a coffee table...plan to make at least one cannon barrel from one of the legs...who knows what for the rest