Compound Delete

[current_resident]

I've seen a number of posts around the net that were about deleting the compound to increase rigidity. Thought I'd give it a try. An hour of turning, boring, threading, and I came up with this. Rigidity is WAY better. No movement what so ever. Plus, if I ever need to use the compound again, all I have to do it remove the set screws and the original compound goes right back on. If you are having rigidity issues, I'd definitely

current resident, you might consider drawing up the solid spacer and putting it into Downloads to save someone else the trouble of determining the exact height and other details of the compound replacement spacer. I'll have to clear it with the head admin but I think that would be worth a free year of upgrade to Downloads. (donor) status.

recommend this.

 

[projectnut]

I'm surprised that so many members are considering modifications to eliminate the compound. I would be interested in knowing what brand machines are needing these modifications. I have a 1960's era Sheldon, and an early 1900's Seneca Falls machines and neither of them have rigidity issues. They are both used hard (within their capacities) and can easily produce parts to well within the spec range, with excellent finishes.

 

[Ultradog MN]

I'm surprised that so many members are considering modifications to eliminate the compound. I would be interested in knowing what brand machines are needing these modifications. I have a 1960's era Sheldon, and an early 1900's Seneca Falls machines and neither of them have rigidity issues. Thy are both used hard (within their capacities) and can easily produce parts to well within the spec range, with excellent finishes.

Agree.
Are they trying to take a 1/2" depth of cut at a very high rate of feed on something?
Maybe using a looong boring bar?
Making interrupted cuts on rough castings?
Inquiring minds want to know...

 

[Lo-Fi]

It's an accuracy thing as much as rigidity, though the two are closely linked... Robin Renzetti and Stefan Gotteswinter both have great videos on the subject and run their lathes with solid blocks instead of compounds unless needing to turn tapers. It eliminates the source of movement that's unavoidable in the slideways of the compound, as well as any chance of movement between cross slide and compound. Extra useful on a DRO equipped lathe with QCTP as the tools can only be in one position - you can't have the compound making movements the X-Z DRO knows nothing about, and hence your saved tool offsets are accurate.

 

[jwmay]

I made one because I’m a sheeple. Anyhow, I’ve put the compound back on since then. I kept the solid mount I made, just in case I ever felt like I needed it for some reason. But I’m back to using the compound all the time. I do have a rear mounted parting tool though, and a very heavy duty aftermarket cross slide. It’s an Atlas 10” lathe, fwiw.

 

[homebrewed]

I made one for my 7x12 mini lathe. It really had problems with parting-off stuff until I made a riser block to replace the compound. The compound is pretty narrow on these machines so it's relatively easy to disturb it with the kind of cutting forces you encounter while parting-off.

Normal turning/facing don't seem to care much either way, at least how I do it but I usually stick with relatively small DOCs. Knowing your machine is the best way to get good results!

Locking the compound might be a relatively simple alternative. As always, a sharp parting-off blade at the correct height is required no matter how your lathe is configured.

 

[wa5cab]

I can see how it would work OK for normal turning but what about for threading? Normally for threading, one sets the compound around to one half of the thread's included angle and most if not all of the cutter advancement is done with the compound feed. Or am I missing something?

 

[homebrewed]

I can see how it would work OK for normal turning but what about for threading? Normally for threading, one sets the compound around to one half of the thread's included angle and most if not all of the cutter advancement is done with the compound feed. Or am I missing something?

That's why I didn't get rid of my compound . But now if I had to I could cut threads without the compound. I could use my z-axis DRO and handwheel on my lead screw to approximate the motion of the compound set at 29.5 degrees. One nice result of this approach is that your cross slide directly indicates the depth of the thread you are cutting so you are getting something back for the additional work of advancing two cutting axes.

Some don't bother with setting the compound over, they just plunge cut. This approach also doesn't require a compound.

 

[jwmay]

I can see how it would work OK for normal turning but what about for threading? Normally for threading, one sets the compound around to one half of the thread's included angle

Tailstock mounted dies don’t care what angle the compound is set to. Sort of a cop out maybe, but that’s how it is in my shop.

 

[Ultradog MN]

That's why I didn't get rid of my compound . But now if I had to I could cut threads without the compound. I could use my z-axis DRO and handwheel on my lead screw to approximate the motion of the compound set at 29.5 degrees. One nice result of this approach is that your cross slide directly indicates the depth of the thread you are cutting so you are getting something back for the additional work of advancing two cutting axes.

Some don't bother with setting the compound over, they just plunge cut. This approach also doesn't require a compound.

To each his own I guess.
I learned to cut threads, short tapers and accurately face things off using the compound.
Now I'm hearing get rid of the compound, make or buy a doohicky to replace it and get a DRO which I've never needed.
Nah, I'll continue doing it the way I was taught.