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lathe work question

6.1K views 21 replies 15 participants last post by  Insaneride  
#1 ·
so over christmas i picked up a grizzly 9x18 metal lathe, it does not have a taper attachment like ive seen on some of the youtube videos. can anyone explain how you would cut a good taper without it? im just not getting it
thanks
 
#2 ·
I did one years ago between centers in a face plate with a drive dog just offset the tail stock, it worked but took forever to lay out I was 16 at the time so who knows if it was actually true I hadn't heard of bluing to check
 
#3 ·
You can turn the compound slide to the desired taper you want to cut and then crank that dial for your feed. It works best if the length of taper you are cutting is less than the travel of your compound but you can cut longer ones by cutting what you can with the travel you have then moving the carriage down and starting over.

You can also offset your tailstock(if it is adjustable on that lathe) the desired amount and turn your piece between centers. Using a bell end center drill for the centers is best.
 
#4 ·
Can you let people know what type of taper you are trying to make?

If it is a gradual taper over a longer distance, have you looked at off setting the tail stock? If you move the tail stock towards you and cut towards the tail stock that end will be smaller in diameter. If you move the tail stock away from you and cut towards the tail stock that end will be larger in diameter.
 
#5 ·
well i have been watching youtube videos on lathework for beginners and it seems that most of the beginner projects are hammers and scribes. and they both seem to want tapers in the handles somewhere i assume because it is a basic lathework operation. also i dont think that my tailstock is offsetable (is that a word?) and so you know what machine i have it is this one http://www.grizzly.com/products/9-x-19-Bench-Lathe/G4000
 
#7 ·
There should be an index mark on the tail stock and a few screws holding it in place.
You can loosen the screws and move the tail stock to get the offset for the taper.
It may take some trial and error.
In order to center the tail stock again put a sharp center in the tail stock, remove the chuck and put a sharp center in the head stock. Move the tail stock until the tips touch and tighten it down

Sent from my SCH-I535 using Tapatalk
 
#8 ·
There's a couple of videos showing homemade taper attachment. Here's one:

[video=youtube_share;xTSmyurlDus]http://youtu.be/xTSmyurlDus[/video]

I'll going to build one for my lathe eventually.
 
#10 · (Edited)
As a beginner I'd recommend rotating the compound and turn it down a few inches at a time then smooth the transitions with a file. It's a handle taper not a tapered fit.

For longer tapers offsetting the tailstock is easy but can take so patience to setup. Maybe this animation will help. You'll need to learn how to dial in your tail stock when finished... of course you'll need to learn that as I doubt the tail stock was dead on from the factory. ;)

Alternatively you could buy or build and offset tailstock center. Google "royal offset live center" for the money is no object version.

[video=youtube;z3iYhKFPHKc]https://www.youtube.com/watch?v=z3iYhKFPHKc[/video]
 
#11 ·
One thing we did in the shop training was to learn how to cut a taper by offsetting the tail stock , this will also teach you how to set the tail stock back to cut a straight piece without any taper. You can do this by cutting a piece untill it is straight , also it can be bone with a Dial indicator. One tool you should buy if you do not have one.
 
#15 ·
Usually there's vibration, but there can be many different causes for it - 1) the carriage may have some play along the ways (tighten the gibbs), 2) tool post stiffness, 3) tool bit too far out (shorten the reach to stiffen the cutter), 4) heavy cuts can make the cutting bit bounce (take lighter cuts), 5) feed too fast (slow the feed), 6) dull cutting bit, 7) bad geometry for cutting bit (bit grabbing and releasing), 8) Lack of lubrication or 9) difficult material to machine (some materials are just gummy and grabby like lead and copper). A lot of it you learn by trial and error.
 
#13 ·
Ribbed surface on a lathe turned piece is from vibration and the dull tool is responsible.


...zap!
 
#16 ·
ok ive ordered a chuck for the tailstock and have some drill starters so i will soon be able to support the end of the tailstock, and ive been playing with with feeds and speeds so maybe ive just got to experiment some more. the odd thing is that it doesnt happen when turning brass?
 
#17 ·
Often people use the half nut lever instead of the feed lever. To get rid of the ribbing you need a finer feed or a larger radius on your tool bit. Generally the half nut lever used only for threads is the most right on the apron. The feed lever operates the carriage as well as the cross slide feed and moves things much slower than the half nut lever.
You will have to fiddle around with the levers. Rule of thumb is that if the control is on the apron you can shift it while the lathe is turning. Any controls on the headstock you stop the lathe first. When you play around with your apron controls make sure you are clear of the chuck because the carriage can move pretty fast and get you in trouble if you can't react fast enough.
 
#21 ·
And Morse/Jarno/B&S/R8 tapers (and sockets) for tooling, and taper pins and...

They're rare on HOBBY lathes, not so much on toolroom lathes... Using the topslide for taper turning you'll be pushed to get an even finish due to the varying feed (unless your lathe is blessed with a powered topslide), end up having to file/emery/polish to fit & finish, adds a lot of time to the job

Dave H. *the other one)
 
#19 ·
I once saw a guy wrap a string around the cross slide screw shaft and attached the other end to the tailstock. So as the carriage traveled towards the headstock the string pulled and turned the cross feed screw. Adjust the size of the 'whatever' the string wraps around on the feed screw to adjust the taper.
 
#22 ·
trunkz, You can calcuate offset using Tangent function on a calculator.

Example: you want a 2* taper for your handle of length say 10.
To calc offset on tail stock you take Tangent of 2* = 0.035 .
0.035 is = offset / length (10).
Using algebra re arrange equation to 0.035 times 10 = 0.35.

The 0.35 is your offset at tail stock for a 10 length handle.

There is other ways to use Trig to find your offset but this is just what came to mind.