When to back the tool out from the work?

[Bill Brehm]

This is probably so basic I should know the answer, but I am a hobbyist and new at proper techniques. I did a search here, and looked through several of my books, but didn't find anything about it.

When you return the tool back to your starting position should you back it away from the work first, or is it ok to let it take off that small amount of material by leaving it in place? I assume that the work is pushed away slightly when the cut is made which results in that material being removed.

Thanks
Bill

 

[Bob Korves]

If you are roughing and will be making successive passes, and do not need a precision measurement, you do not need to retract the tool from the work. On work that does not need to be cosmetically pretty, you also do not need to retract the tool. Leaving the setting alone will hold the setting the same as you set it, which is sometimes an advantage. For a better finish, retract the tool before the return for most work. Not sure, but some cutters may not like being returned at high speed while in contact with the work.

 

[brino]

I assume that the work is pushed away slightly when the cut is made which results in that material being removed.

I believe it more likely to be caused by tool flex while cutting.
In fact many people take a final finish cut at the same tool depth as the last cut , it's called a "spring cut" or "spring pass"

-brino

 

[Reeltor]

What they said, I don't know if it's me or my mill but if I don't retract the bit when using a small diameter end mill (when milling a slot) I'll snap it more often than not.

BTW there is no such thing as too basic a question

 

[eeler1]

Also what they said. Plus, when I retract the tool, I'll go a full revolution of the dial, back to the original setting on the dial, but one turn out. That's how they showed us in school. I can't say how many times I've retracted the tool, measured or somehow got distracted, and forgot where I was. Then had to find my place all over again. Takes out backlash too. Just a practice I've found to be helpful ,fwiw.

Or you could get a dro and not have to worry about any of that stuff.

 

[mikey]

I think this sort of depends on your work habits and which tooling you're using. I always back the tool off before coming for the next pass; this is to remove the backlash in the cross slide feed screw so my next depth setting is accurate. If using inserted carbide tools, backing a cutter out can chip the insert. I've had this happen only once but it was enough to make me take notice. 95% of the time I use HSS tools and they can be backed up with no issues for the tool but I do it anyway, for the accuracy thing.

 

[Professor64]

Backing out tool is a matter of preference.A combination of workpiece and tool deflection is what leaves the backtracks in the workpeice.It all depends on setup and rigidity of the tool and workpeice.On finish cuts I like to pull out, retouch, dial the cut and go.Get the feel of the machine on which you are working and then decide.All machines are different as well as wear patterns.Experiment and have fun.My 2 cents--Glenn

 

[Cobra]

I will normally back the tool off to return with the exception of running a short piece to measure for setting the DRO. Then I don't want to move the tool until I have set the dimension.

 

[Bill Brehm]

Well, that was an education. (I mean that seriously) Thanks you for the information.

Jim, is that your Cobra? I remember going to Mid Ohio in 62 and seeing them for the first time. What struck me most was the smile on Ken Miles face as he drove it, he was definitely having a good time. If it's yours, do you have any photos on this forum? Love to see it.

 

[Cobra]

Well, that was an education. (I mean that seriously) Thanks you for the information.

Jim, is that your Cobra? I remember going to Mid Ohio in 62 and seeing them for the first time. What struck me most was the smile on Ken Miles face as he drove it, he was definitely having a good time. If it's yours, do you have any photos on this forum? Love to see it.

Hey Bill.
Yes, it is my car (or toy if you're talking to SWMBO)
It is a Factory Five that I finished in '05.
Mostly cruising but we have a road course about 2 hours away that I have had the car on.
Sorry, I have not put any photos on the site.
Do you have an interest in building?
Jim