[MyStrat]

I worked in a cabinet shop for many years...was laid off, now I am in school for CNC machining...to make a long story short, I ordered a 1 1/2 horse mill from Harbor Freight,, special order item so no chance to inspect it before buying. Read one good review on it before, but have found a few digs on HF stuff as well.

Anyone out there own one of these beasts? Am I going to regret this impulse buy? I worked with a few machines made in China in cabinet shop. some needed a lot of re-engineering to get all the slop out.


I'd like to convert it to CNC in the future if it holds up. Most of what I plan to use it for is making parts needed to make a VW tryke, and small parts for guitars (bridges, etc).

thanks for any input

[Crevice Reamer]

Hi MyStrat. Welcome to the Zone!

A round column mill is a poor candidate for CNC conversion.

The head can swivel out of alignment any time you change height. (Or change a tool mid job.)

The only way to CNC Z movement is by the quill--Which is both limited in movement and lacking rigidity.

If you have CNC in mind, you really should be buying a dovetail column machine.

CR.

[MyStrat]

Thanks for info,
Guess I might get DRO and leave it at that

[BillTodd]

Ignore the nay sayers, say I.

I intend to convert my RF30 type round post to cnc and there are plenty of others who have already done so:

http://www.mycncuk.com/forums/showthread.php?t=651

As for the losing alignment when shifting the head, this is my attempt at a fix:
http://www.cnczone.com/forums/showthread.php?t=70099

And I fixed the back-lash in the lead screws with these:






design here:
http://www.cnczone.com/forums/showth...=13593&page=52

It starts here (and goes on a bit!)

http://www.cnczone.com/forums/showth...=13593&page=36

[MyStrat]

Thanks for the info...I have to admit, I understand about 1/10th of what you are talking about...know all too well about the backlash thing..learning machining on bridgeport mill, like it, but didnt realize how much it came into play....thanks for the info..will look into it and try to understand it more

[George FM]

Who has Harbor Freight 33686 conversion kit for sale?
Hope to hear from you soon.

[George FM]

Who has Harbor Freight 33686 conversion kit for sale?
Write to [email protected]
Hope to hear from you soon.

[LUCKY13]

The round column problem is when you move the column it tends to turn a little even if yo wish to just move it straight up or down. When CNC this causes a problem because now the CMC software doesnt know exactly where the bit is ( because it may have turned a little onthe round column from moving Z ).


The quick way around this is to CNC the quil for the Z axis and try not to move the head on the round column within a job. The problem with a quill being CNC is they are not as ridgid and will always have a little play/slack in it.



Now much depends on what type jobs you wish to do, but we are talking thousands mostly when we say the quill will have play. Many jobs this doesnt hurt but when it comes to CNC we always want to be as good as possible, simply because it just should be.


Many people have run these machines on CNC with good results. But they do have to work around this round column problem and they dont have the rigidity that a square column mill would have.


So I say go for it, and make the best of it. There are things you can do to help the quill, and learning to not let the round column problem get in your way can be done, all though it will limit you in some ways. AT the worst when you move the head on the column you owuld have to re zero the machine ( or atleast Z axis) so the CNC controller knows where its at.



Now on another hand though, you will have some veratility that a square column mill would not have. Mostly this part comes in handy for wood workers but still it can come in handy to be able to turn the head on the column.


The quill, all though it would take some work and modifying, can be made to have no slack. Heck all though I have never seen anyone do this a power lock for the quill could be designed and help the problem out. Either way its not a deal killer and your machine will be usable, but it would have been better to have bought a square column unit.


Look for RF-31 machine CNC converstions and you will learn more & understand more about the mills design and how it effects CNC. You will be fine, but with a little extra work, or even head acks you might say, when using the machine. FYI, a square column mills quill are no better, they just have the dovetail column to used instead of the quill. Most people even lock the quill down when they CNC them ( to get rid of the slack).



Jess