Cut Bevels On Manual Lathe?

great white

great white

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I've cut small bevels on the shoulders of cuts, but I always end up using the profile of the cutting tooling.

Is there a procedure to cut things like a 45 degree taper on a shoulder using the compind or cross slide?

Probably the ultimate noon question, but I can't seem to wrap my head around it without using the compound and cross slide like an "etch a sketch" movement.

A video would be cats rear. I can't seem to find one that shows what I would like to do...
 
I ground a 45 degree tool for chamfering the edge of shoulders and ends of bars. Sort of like a threading tool except with a 90 degree included angle instead of 60 degrees. It can be aligned in the tool holder either perpendicular to the work or on the work axis whichever the set up requires. Mine is in a QCTP holder.

Tom
 
Small bevel or chamfers are probably easiest to just slab cut, but the bigger they get, the more likely they are to chatter, or sometimes it's difficult to get a tool on. Standard practice is to set the compound to the desired angle and use a tool with proper clearance to cut it while hand feeding the compound. Internal 45° chamfers are typical of this, and if you have reversing spindle capability, you can use the boring bar and compound to chamfer the OD of the part on the far side. Pretty much the same process for all angles.
 
Ah, tubalcain. Always a good archive to search for how to techniques:

[video]

So simple. I don't know why it was toppling my gyros....:rolleyes:
 
great white said:
I've cut small bevels on the shoulders of cuts, but I always end up using the profile of the cutting tooling.

Is there a procedure to cut things like a 45 degree taper on a shoulder using the compind or cross slide?

Probably the ultimate noon question, but I can't seem to wrap my head around it without using the compound and cross slide like an "etch a sketch" movement.

A video would be cats rear. I can't seem to find one that shows what I would like to do...
Click to expand...


You can turn the compound 45 degrees. I like to turn it so the handle is over the ways so I can cut from the inside diameter to the outside diameter. I took small cuts so I could control the length of the taper. Don't forget to clamp the saddle so it doesn't move on you.
 
When I do angles on a manual lathe I set the compound to the desired angle on the back side and run the spindle clockwise, this puts the handle on the compound in front of the lathe rather then reaching over center to operate it. This is much more pleasant in every way, assuming that you have the tools to do it that way of course.

A boring bar works well for this by the way.
 
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I was watching the Tubalcain video above and noticed what I thought to be a fair degree of movement in the center drill (right at the start of the operation). I've never looked at any center drilling I've done that closely. Is it normal for a center drill to pull away to one side that much? I like watching his videos - I alway learn something new (keeping the wrench on the carriage lock to remind you not to engage the carriage feed with the bolt locked down is a great tip). I've never even thought about that possibility - which I assume would be bad for the lathe.

Rick
 
If you are starting with a saw cut, for example, it's common to have the center drill push off, but you should use a pretty gentle touch at the beginning to minimize that. The very tip of the center drill should really act more as a boring bar would, stiff and corrective of any off center tendency. Don't extend the ram any more than you must to do the job to give it all the rigidity you can. If it's sloppy in the ts bore, maybe even snug the lock just a bit.

On a short piece that has been faced previously, or a flat plate, you shouldn't have a noticeable amount of that. If you do, then likely something is out of alignment. You can also watch carefully as you retract the drill and see if it drags on the side of the new pilot hole. It shouldn't.
 
I do not use a center drill for any other purpose then creating centers. Use a spotting drill for starting holes, your finish drill bits will thank you, if the spotting drill is large enough it will also chamfer the hole at 45º eliminating a second operation.
A bit spendy for hobbyists however but last a very long time when used for it's intended purpose.

http://www.mscdirect.com/browse/tn/...ng-Drills-Sets/Spotting-Drills?navid=12106130
 
Surprman said:
I was watching the Tubalcain video above and noticed what I thought to be a fair degree of movement in the center drill (right at the start of the operation). I've never looked at any center drilling I've done that closely. Is it normal for a center drill to pull away to one side that much? I like watching his videos - I alway learn something new (keeping the wrench on the carriage lock to remind you not to engage the carriage feed with the bolt locked down is a great tip). I've never even thought about that possibility - which I assume would be bad for the lathe.

Rick
Click to expand...
that is exactly what i noticed some time ago when i saw that video
his tailstock quil is lifting, it is not just the center drill moving
 
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