Milling with Lathe Attachment

Dranreb said:
Hi nuturner, I've done a bit of lathe milling and as has been said you need to tighten everything up and adjust carriage gibs very snug. Also adjust the gibs in the milling slide very snug.

If you are moving the cross slide lock the milling attachment with one gib screw, likewise if you're moving the milling slide lock the cross slide with one gib screw.This will eliminate lead screw slack in the non moving part.

Best not to use the carriage wheel to move the carriage towards the chuck, engage the half nuts and turn the lead screw by hand to advance the work onto the cutter, this gives much smoother control but may involve cobbling up a crank handle on the end of the screw.

As has been said a collet or at least a Jacobs chuck should almost eliminate an intermittent cut and will feel smoother.

I'm sure there's more I could add but it's been a while since I used mine, don't give up, I managed to make this using a milling attachment for quite a lot of operations.

http://www.hobby-machinist.com/show...a-new-apron-gear-case-10F-11-using-lathe-only

Bernard
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Now using a Jacobs chuck to hold an end mill/cutter can be a problem. The typical drill chucks jaws are tapered down to a very narrow jaw grip, some go to a wedge/chisel point (the chucks that close to “0”). They are almost worthless for holding anything that will involve a side thrust load. If the chuck was subject to a side thrust load. The jaws would instead act like 3 chisels and your part/tool will wiggle loose. A collet on the other hand, has just the opposite in surface contact for holding. It’s an excellent choice for side thrust loads…Good Luck.
 
chips&more said:
Now using a Jacobs chuck to hold an end mill/cutter can be a problem. The typical drill chucks jaws are tapered down to a very narrow jaw grip, some go to a wedge/chisel point (the chucks that close to “0”). They are almost worthless for holding anything that will involve a side thrust load. If the chuck was subject to a side thrust load. The jaws would instead act like 3 chisels and your part/tool will wiggle loose. A collet on the other hand, has just the opposite in surface contact for holding. It’s an excellent choice for side thrust loads…Good Luck.
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Thanks for the info chips, :thumbzup: I suggested a Jacobs in case he didn't have collets and because they are more accurate than a three jaw, bad move!

It would need a drawbar too....I've never used one for milling but have seen pics of it being done.

Bernard
 
I dont have any practical experience but in thinking I would tend to agree with chips. The run out in a chuck would only really affect the slot size. Might be a touch rougher on entrance but after that it's just acting like a larger end mill or tiny boring head. Like taking the first cut on a lathe with a out of round piece. Tink, tink tink, until it's in the work then it's business as usual.
 
With a lot of runout only one tooth will cut. Even if you are boring the side load on the work will cycle around and around at the spindle speed. If you are side milling the side load will come and go as that one tooth goes in and out of the work, like an interrupted cut. Sometimes the force on the carriage will be upward. You'll be hammering it up and down and back and forth. Lots of vibration, lots of opportunity for chatter if anything can bend or move the least bit.
 
in my limited experience of milling in shaky setups, you're best off using a smaller cutter (ideally a roughing end mill) to remove the bulk of the material, then finish to size with another cutter. Making a full depth cut like that will lead to a lot of chatter, as you can see from the finish of your cut. Takes a while to get used to the speeds and feeds that work well too, experiment and you may find higher speeds and less depth of cut work better. Oh, and WD40 in the cut doesn't hurt either :)
 
I can see both sides of it for sure. I just think it would have to be a pretty sloppy chuck to do so bad. I would think the end mill would cut till it was dull or broke so long as your easing into the cut. I know I got a drill press thats bad enough you can watch it wobble. It will drill a hole just fine(relative to the wobble) long as you dont feed it much. I dont use that POS but it will make a hole
 
A typical feed per tooth for a 3/8 HSS end mill is .002". That's not much slop for a 3-jaw.
 
How are you mounting the milling attachment on the cross slide? You probably need to make a base to hold it down well.

Cheap and easy way for a crank is to add a handle to an extra 80 tooth gear on the headstock end of the leadscrew. I went through the trouble of putting one on the tailstock end before I changed beds and it was a pain.

Small cutters and make sure if you can, let the cutting force be down towards the lathe bed instead of up. You also might have a bit of backlash on the cross slide.
 
A collet is really the best answer. A jacob's chuck will be hanging out just as far as the chuck is,with only a puny #2 MT holding it on. That is WORSE than a chuck,which in your case is at least attached more firmly to the spindle.

I think expecting a 3/8" cutter to cut o.k. is expecting way too much from the little lathe,unless you only are milling brass and aluminum. There are still chatter marks in the end of that cut. It may be better than you got before,but it still isn't fully there yet. Try that in steel,and you'll be in trouble again. My first mill was an Atlas,and it would mill brass and aluminum,but steel only with a narrow cutter. I did not have the outboard spindle support,but the whole knee and table would jerk badly. The answer: I got a Burke #4,a small,but REAL mill. If you can manage the space,try getting a heavier machine,and NOT a mini mill.
 
I've milled several items with the mill in a three and four jaw chuck. Mills up to 1/2"dia. on a 13-36 lathe. Only problem with using a three jaw chuck was a couple thou runout.
Just feed slower as only one or two teeth are cutting.
Have since done some scraping and made and fit new gibs on the lathe.
Though it was able to handle the 1/2" mill before I had to take light cuts and use a smaller dia. tool to rough out the slots.
When scraping I found both the cross-feed and compound slides had only two corners contacting and they rocked on the surface plate. Took a lot of scraping.
Lathes much more stable now.
It would be a good idea for you to check your machine.
 
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