# 1018 Finish Cut



## Jim1946 SB9" (Mar 14, 2015)

Hi everyone. 
Well I have started my first project on my 9" SB. I am struggling with surface finish I am cutting 1018 and want some pointers on finish cuts. At this time I still have lots of material to remove but would like to figure this out before I get to my final dimension. I have been reading about feeds and speeds but have yet to try power feed as I am not sure what feed rate to start with. Any advice about 1018 would be appreciated.


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## JimDawson (Mar 14, 2015)

I guess on a 9'' SB I might start with a 0.005 feed and a 0.010 DOC (Depth of Cut) and see if produces the desired result.  In general a finer feed will give a finer finish.  Play with the tool height and shape also.  1018 is not known to produce mirror finishes, too slow of a spindle speed or too slow feed will sometimes cause some galling at the tool point and produce a intermittent rough finish.


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## randyc (Mar 14, 2015)

You've picked a material that is noted for being difficult to obtain a good surface finish.  However it is common and inexpensive, most of us use it often.  Insofar as feeds and speeds are concerned, it may be a trial and error process on an older lathe.

Start with a lower RPM and fine feed and experiment by gradually increasing both, noting the results.  (Be sure to use a sharp cutting tool or any observed results aren't meaningful.)

If your lathe is tight and solidly mounted you might set your starting RPM at about 200 divided by the work diameter in inches, for steel workpieces and sharp HSS cutters.  If you use carbide cutting tools, the RPM can be tripled.  Again, this is for steel.  Use cutting lubricant to extend tool life - unfortunately it won't help the surface finish on 1018 as it does on most materials.

You probably aren't at a stage of development yet to make use of this but for a precise, finely finished diameter in 1018, a HSS "shearing tool" does wonders.  The depth of cut must be very, very small however, typically around .001/.002 to prevent wear on the cutting edge and the feed rate must also be very small, on the order of .003 IPR.

Oops, Jim posted while I was bumbling around with my own reply.  His advice is always good


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## chips&more (Mar 14, 2015)

When you finally get tired of cutting 1018. Try some 12L14. It’s a free machining low carbon steel with similar properties to 1018 but with some lead in it. It machines amazingly nice…Good Luck, Dave.


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## Jim1946 SB9" (Mar 14, 2015)

Thanks guys. I have been messing around just trying to learn how to use the lathe. If all goes well the project will turn out to be a cannon. But I think I started a little big for the 9". I have a few 9" deep holes to do on this project and wanted a decent surface finish. So I think I will just learn to get the taper cut and will probably purchase some of that 12L14 for the final product and maybe down size it a littl. This is all about learning, the finished product is in my future but it might take a couple tries. Learning is the important part right now. I will be reading about that shear tool as much as possible and see if I can get one of those made up.


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## zmotorsports (Mar 14, 2015)

As others have already mentioned 1018/1020 mild steel is not well known nor easy to get a nice finish on.  If you are after final finish then I suggest stepping up to some more free machining steel, again, like already mentioned.

That said, I use 1018/1020 a lot because a lot of my work includes welding as well as machining.  The 1144's, 12L14's are not conducive to welding so I have had to learn to work with mild steels.

I have found that HSS tooling seems to work best but carbide inserts work well also if you are willing to take off heavier DOC's.  I will usually rough out down to within .011-.012", then take a .010" finish cut, leaving a thou or two to be removed with  a fine file and/or emery paper creeping up on the final dimension.  I will start at around 80 grit and end up somewhere around 400 or 600 grit final.

The last finshing with sandpaper takes some time and time is money, so I generally will cut with carbide inserts and take a lot of material up until the final cut.

Seems to work for me if finish is what is needed.  Otherwise I will make the final cut with HSS and let the finish be if it is not 100% necessary to have a nice finish, but I don't like doing that unless the part is not going to be seen at all.  Even then it is not something I really like doing.  It just turns out to be a balancing act of form vs. function.

Mike.


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## randyc (Mar 14, 2015)

Don't give up on the 1018 just yet, LOL, there's no need to use a shear tool to obtain a satisfactory finish.  In fact, old-timers would probably lift their eyebrows at the use of this tool.

Conventional practice was to turn the work to about .002 oversize.  The work was then brought to finish diameter with a file and emery paper.  It sounds like a crude process but with care and patience good finish and accurate diameters can be achieved, as Mike noted.


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## Jim1946 SB9" (Mar 15, 2015)

Well I tried the Shear tool. All I can say is Wow it works. Very early in the process and still need to experiment with DOC and Feed and such but so far this Shear tool looks promising. Will probably still need a little emery cloth to finish but much less effort than starting with the ugly surface I had before.


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## dracozny (Mar 15, 2015)

I keep a set of files and sandpapers on my bench for this purpose. you can get close to a mirror finish but it is so random. This material I often think is not completely homogeneous when you start to really look at it. It's also very soft and dings easily.


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## Wreck™Wreck (Mar 15, 2015)

I can only guess at the diameter of the work that you are doing, a 9" Southbend lathe leads me to believe that it is less than 2" however. If using inserted carbide tooling turn the spindle up to it's maximum speed, rough at around .020-.035 DOC at .008-,015IPR  feedrate, finish at max RPM at .005 or so DOC at .003-.006 IPR feedrate with flood coolant using positive rake tooling with a maximum 1/64" nose radius tool. This should get you in the ball park
Good Luck


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## JR49 (Mar 15, 2015)

Jim, you have gotten some great advise already. All I want to add is TRY USING POWER FEED, it is impossible to hand feed as precise as the power feed (yes, I'm saying machines are better than Humans).  I couldn't believe the difference for this novice.  Happy Sunday, JR49


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## Jim1946 SB9" (Mar 15, 2015)

Awesome advice so far. Wreck it is 2" and I don't currently have any carbide stuff. I will keep this in mind when I finally get some. Not sure the old Southbend could ever use it at its max production potential but I am sure there are some things I could use it for. 

I wanted to show this photo of what I was getting and where I am now after trying the shear tool.


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## itsme_Bernie (Mar 15, 2015)

Looks like you may need to round the end of your tool a little - a good hone-  and make sure the power feed is set as fine.

Bernie 


Sent from my iPad using Tapatalk


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## randyc (Mar 15, 2015)

Jim1946 SB9" said:


> Well I tried the Shear tool. All I can say is Wow it works. Very early in the process and still need to experiment with DOC and Feed and such but so far this Shear tool looks promising. Will probably still need a little emery cloth to finish but much less effort than starting with the ugly surface I had before.



Jim, the shear tool may seem like the ultimate answer at first but it _does_ have shortcomings including _very_ small DOC and feed.  The cutting edge can wear quickly resulting in a tapered diameter over long workpieces.  What's worse is that the wear is not usually eyeball detectable !  Takes a little magnification to see the tiny little wear spot.  (This is one of the times when you _should _use lots of cutting oil on 1018, to minimize the tool wear, by the way.)

This won't be a problem for general work but one of the main uses for the shear tool is not necessarily to produce a good finish but to obtain very accurate diameters, shaving off a few "tenths" at a time using the compound set at about 6 degrees off the spindle axis (google it and you'll understand the technique).

A little taper can be an important problem - for a bearing fit as an example - and then one is right back to using a scrap of emery paper to straighten out the taper 

Good on ya' for trying it out, though, best way to learn is by doing !  (FWIW one time I tried a brazed carbide AL tool as a shear tool after honing the edge with a diamond lap, and got some good results.  Was able to run the spindle faster with less tool wear although this won't be an advantage on your South Bend with its limited maximum RPM.  I still used very small DOC and feed, however.)


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## kwoodhands (Mar 26, 2015)

Jim1946 SB9" said:


> Hi everyone.
> Well I have started my first project on my 9" SB. I am struggling with surface finish I am cutting 1018 and want some pointers on finish cuts. At this time I still have lots of material to remove but would like to figure this out before I get to my final dimension. I have been reading about feeds and speeds but have yet to try power feed as I am not sure what feed rate to start with. Any advice about 1018 would be appreciated.




Grind an arc shape on HSS .The front relief  7° / 10°. The cutter should look like a C shape when looking down on the cutter. The radius is about 1/16". Grind the top and side rake about 5°. You may have to stone the cutter if there are any burrs.Center the tool on the work. Place a 6" steel rule between the cutter and the work.If the rule is plumb the tool is centered. If the top of the rule is away from you the tool the tool is high.If the rule is towards you the tool is low.
Once you are set up, use the powerfeed on the slowest travel. Spindle speed set about 350 rpm,not critical.Make your cuts .005 or so at first.You will be removing twice that amount when turning.Use a cutting oil, I use plumbers thread cutting oil on 1018.If you grind the HSS cutter like I said ,center it , use a lubricant ,the finish will be much better.
Usually I can turn a shaft or axle so none or almost no other work is involved. If you have to sand or file, then make light cuts instead. The most you should have to do is 400 grit paper or scotch brite pad.Don't be afraid of the powerfeed.
When you get close ,especially at the lowest travel speed you have plenty of time to stop the feed.
mike


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## l. bacon (Mar 28, 2015)

Some thoughts I have on this finish subject: A manual lathe is a thread cutting lathe. no matter whether it is cutting a 8 thread per inch or .005 per revolution. Look at your rough surface with a magnifying glass or under a microscope and you will see what I mean. So a pointed tool will leave a threaded surface or that rough surface that you don't like. To smooth that surface, a tool with a less point should help. A tool that is wide, straight and parallel with the work surface will work but will likely chatter and leave an uneven finish, so a tool that is only as wide as to bridge across at least two threads should leave a smooth surface ,but it will probably be too difficult to adjust perfectly parallel to the work. A rounded tool that is wide as described previously is what seems to work best. It cuts out at least two of the previous threads and isn't so wide that it chatters. Of course there are other things that can cause a rough finish such as a loose and worn machine, dull or sharpened with poor relief angles, and all the other things mentioned in previous posts.

I hope this helps. This is just my 2 cents worth.


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