Tapered Face

[jrrdw]

I'm making a arbor for some grinding disk i just got. The center of the backing pad is recesed to acomadate the arbor and bolt head. When turning the taper on the arbor, whats the best way to go about it. My lathe is totaly manaul, minus the leed screw for cutting threads. I don't have use of my right hand, i can't grip the wheel handle to turn two hand wheels at once. Tieing my hand to the machine is out of the question, safty reasons.

Any sagestions?

[under-dog]

You want to use a compound slide. Most lathes come with one.

I am not trying to sound pompous with this. I am writing this with the belief that your lathe either does not have one or you are unaware it does and what its purpose is.


It is a small adjustable tool mount/slide that sits on the cross slide table that saddles the lathe bed. It can be set to the desired angle and has its own lead screw so that it can drive your cutter along that angle to the workpiece.


Here is a link to Sherline's. I know it isnt the best example of a full bore compound, in some ways but it was the first I found and it gives a picture and a downloadable instruction sheet on how to use a compound slide. It should give you a firm understanding of what I have so loosly described. Good luck and happy cutting.

http://www.sherline.com/1270pg.htm

[Geof]

You can also turn a taper by offsetting the tailstock. When the centerline of the tailstock is exactly in line with the centerline of the spindle and you are turning a shaft between centers it comes out parallel. Offset the tailstock by 0.10" and turn the shaft and it will have a 0.20" taper over its length.

You may need too much taper to do it this way but maybe not.

When the tailstock is offset you cannot use regular straight sided center drills to make the center holes you have to use the ones that have a concave taper. This puts a convex taper inside the center holes so the part can rotate smoothly. You might need to Google to find some pictures of what I am referring to.

Also you have to have the shaft between centers you cannot grip one end in the chuck.

Another way to do a taper, which is a bit hokey but can work, is to mount a flat tool at the correct angle for the taper and plunge straight in; this leaves a tapered portion on the shaft. Then move sideways maybe 0.1" and plunge again until your just blend perfectly with the first cut; and keep repeating this.

You need a steady hand for this .

Then polish it a bit with a file and emery paper. One handed filing is tricky but possible. Put a handle on the file to cover the nasty sharp tang just in case you slip.

Yet another way is to rig up a guide strip at the back of the cross slide; a sloping cam with a cam follower mounted to the cross slide.

Then you have to adapt a little 'winch drum' onto the cross slide handwheel so you can wrap a string around it with a heavy weight. The weight turns the winch which feeds the cross slide forward until the cam follower touches the sloping cam. Now you feed the saddle along and the weight keeps advancing the cross slide down the slope.

[under-dog]

Offsetting the tailstock is typically for longer work pieces. The mandrel he is making sounds small and the work involved switching over the tailstock and realigning it afterward sounds a bit tediouse if the compound slide will do the same job.


I do agree however that using a wider tool bit set to an angle is a viable solution for such a small cut.

[jrrdw]

Yes, i have a compound slide. Setting it at a angle still doesn't help me because both hand wheels still have to be turned at the same time. I did the plung turn plung turn before i posted my question, very time consuming, but it worked. Good filing comes second nature to me, i'm a locksmith and have done alot of presision filing on keys. That was the easy part for me.

Hanging the weight is a good idea, just have to do alot of trail and error testing to get the proper speed.

Thanks for the idea's, i'm still open to more or tweeking of the present idea's posted.

When i get it finished i'll post a picture or two.

Thanks again,
jrrdw

[under-dog]

Are you talking about a straight taper or a radius? To cut a straight taper with the compound should only require one wheel. It sounds more like you are attampting a radial surface if you are saying you need to turn two wheels simultaniously

[jrrdw]

Originally Posted by under-dog Are you talking about a straight taper or a radius? To cut a straight taper with the compound should only require one wheel. It sounds more like you are attampting a radial surface if you are saying you need to turn two wheels simultaniously

I'm doing the radius/face taper.

[under-dog]

Thats a tough one. Running both whells with tow hands even gives crude results. I often rough outh that way and finish with a file. I also made a radius cutter.

Do a search on radius cutters. It may be of use

[jrrdw]

Yes, i'll look into that, thanks everyone for your help.

[jrrdw]

Sorry about double post, but i'm proud of the job i did making my grinding disk arbor. Spins true from 10 RPM'S to 25,000rpm's!!! Whoot whoot whoot!!!

Originally Posted by jrrdw Good filing comes second nature to me, i'm a locksmith and have done alot of presision filing on keys. That was the easy part for me. Hanging the weight is a good idea, just have to do alot of trail and error testing to get the proper speed. Thanks for the idea's, i'm still open to more or tweeking of the present idea's posted. When i get it finished i'll post a picture or two. well four Thanks again, jrrdw

Heres a few pics of my home made arbor --