Any Suggestions For 1st Time Lathe Use?

Rob Martinez

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May 3, 2013
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I've got a beginners question on the first use of my new lathe. I did some research and bought a sherline 17" metric lathe. I put a 12" long 1/2" wide round rod of 14L16 steel in the 4 jaw chuck but could only get the play down to .020" (20 ticks on my dial indicator). As my first test with the lathe I tried to start shaving off some metal shavings/curls but all I can get is metallic dust and lots of clatter. I tried to "slow the speed and increase the feed" to stop the clatter but not knowing how slow is slow and what a good feed is I didn't see/hear any difference. Where I cut is far from smooth - many ridges... Bottom Line -- Any suggestions for this literal first time lathe user?
 

UncleDoc

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Apr 4, 2020
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I've got a beginners question on the first use of my new lathe. I did some research and bought a sherline 17" metric lathe. I put a 12" long 1/2" wide round rod of 14L16 steel in the 4 jaw chuck but could only get the play down to .020" (20 ticks on my dial indicator). As my first test with the lathe I tried to start shaving off some metal shavings/curls but all I can get is metallic dust and lots of clatter. I tried to "slow the speed and increase the feed" to stop the clatter but not knowing how slow is slow and what a good feed is I didn't see/hear any difference. Where I cut is far from smooth - many ridges... Bottom Line -- Any suggestions for this literal first time lathe user?
Way too big of a work piece. Cut off one inch piece and place it in the chuck and practice the basic cuts by following the Sherline Manual that came with your lathe. Do a face cut, then turn the piece around and face the other end. Once faced, do basic cuts as well as drilling a center hole and trying out the boring cutter. You did get an accessory package (ie A or B)? RFTM applies as with most thigs you buy.

Duane
 

Rob Martinez

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May 3, 2013
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Good ideas -- I will cut and start again.... but isnt 1" a bit short? I think it would take 1" just to secure a piece in the chuck. Would 6" be too long....thats 1 - 2" in the chuck and 4-5 to cut on.... With the steady rest in place, thats more like 2-3 inches to cut on... Your thoughts?
 

etmb61

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Oct 25, 2010
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Good ideas -- I will cut and start again.... but isnt 1" a bit short? I think it would take 1" just to secure a piece in the chuck. Would 6" be too long....thats 1 - 2" in the chuck and 4-5 to cut on.... With the steady rest in place, thats more like 2-3 inches to cut on... Your thoughts?
Since you are practicing at this point you want to have enough material to work with but not so much to damage the tool or yourself. I find it best to have no more stock than what you need to hold and make the part. The further you work from the chuck, the harder it gets to keep tolerances.
eccentric hub 3.jpg top head 2.jpg

The 4-jaw holds better than the scroll chucks by design, and the jaws are only in contact with a 9/16" length of the part at most. You can do a lot with it. The steady rest is not very robust and I've pulled a piece of stock out of mine and the chuck by trying a too aggressive cut. You should use it when you need it, but not all the time. Here's mine with a custom mandrel to hold a part for boring.
boring setup.jpg
(These are not clock parts.)

Eric
 
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karlmansson

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Apr 20, 2013
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Hey Rob!
The Sherline is a very small lathe, half inch is a pretty substantial workpiece for it. From what you are describing it sounds like the tool is rubbing rather than cutting. Make sure that you tool is sharp but most importantly: make sure that the edge is actually on center height. The most reliable way to do this is to take a facing cut and then measure the pip that is left (if tool is set too low) and increase the tool height by half of that measurement. You can also get in the ballpark by setting the edge of the tool visually in height with the tailstock center.

As a rule, any work where you have a stick out from the chuck jaws that is more than 3x the stock diameter you need tailstock support. There are of course exceptions to this rule and you can compensate for the loss of rigidity in different ways. But for general machining it’s a good rule of thumb.

What you are experiencing is usually referred to as “chatter”. This is a vibration on the resonant frequency of you entire system and is maintained by the interaction between the tool and workpiece. On larger machines this vibration can be dampened by very stiff setups and large masses of cast iron. On an aluminium bed little Sherline, you have to work with what you’ve got. VERY sharp tools with appropriate top rake for cutting steel and have them be exactly on center. Reduce the speed of the spindle and instead put a little more push on the feed. A too small depth of cut or a very slow feed of the tool can also cause chatter from the tool being allowed to run on a surface instead of cut. And that will only amplify the pattern already in the work.

A final note on chatter: if you already have chatter turn up in the work, you can’t turn it down by just pushing harder. Slow the lathe down and cut through. In some cases, as with parting, I sometimes turn the lathe of and scrape the chatter marks away by rotating the headstock by hand.

Hope this helps!

Regards
Karl
 
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gmorse

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Hi Rob,

Definitely start with a much shorter work piece, as recommended above, but also, check carefully that the cutting tool is at the exact centre vertically, and that only as much of the tool as necessary is protruding from the tool holder. Everything can flex!

Regards,

Graham
 

oic55

Registered User
Aug 21, 2009
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Hi Rob,

Slow and steady wins the race...

Sherline has some great videos on their website cutting different materials including the 12L14 (is this the material you have vs 14L16?) under different conditions, speed, feed, w/coolant etc. As folks have mentioned, sharp tool, correct height and speed are important.

Sherline offers a great book, "Table Top Machining" that contains some great info, especially on speed and feed for different materials and different functions, such as turning, drilling, milling and how to calculate based on diameter of material.This book covers a lot of great info that covers not only table top, but machining in general. Another good book is "The Home Shop Machinist" which also has some great projects to start with including tools that will be handy including a brass hammer, and some small screw jacks.

Good luck with your new machine! Stay safe!!

Don
 

Wayne A

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Sep 24, 2019
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Bottom Line -- Any suggestions for this literal first time lathe user?
Read, read, read and watch allot of machining videos!

You will read and see everywhere, rigidity, rigidity, rigidity. If the work can flex your going to have problems. To turn that long of a piece theres the steady rest or use a live center. First project I did with mine was add bearings to the steady rest.
 

motormaker

Registered User
Apr 5, 2010
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Rob,
I would suggest that you find and study a book on lathe use. If there is a local chapter, join and ask to watch a member work at the lathe. If there is no local chapter, see if there is a local model makers club. You could really benefit from a little personal help. These three books are suggested if you are serious about learning.
 
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