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Mill/drill Sqr column ??

JimGlass

Stainless
Joined
Jan 15, 2003
Location
Genoa, Illinois
Looking for opinions on a 20" Square Column Mill/drill that ENCO offers.
63511-milldrill.jpg

My interest in the machine is conversion to CNC. The homebuilt milling machines I have built are just not rigid enough to machine steel. It is unrealistic to think I could build a machine with dovetail ways, spindle and motor for what a mill/drill costs.

In addition, the mill/drill weighs only 750 lb so I'm thinking of building a stand with wheels so the machine can be moved out of my way when not in use. Not planning to machine real big stuff but still see some opportunity in having CNC capability.

The JET 8 x 36 is more attracttive to me but at 1600lb will not be readily moveable.
63511-JET836.jpg


The other option would be to buy an old Briddeport and make it CNC. I should also point out I'm not interested in rebuilding a machine then making it CNC.

All opinions welcome,
Jim
 
Older NC and CNC Bridgeports and especially those that never had hand wheels will come with chrome ways, ball screws and either stepper or servo motors. Lack of handwheels coupled with troublesome controls resulted in a good number of these machines being found with ways and ball screws in very nice shape. If you can stand the weight and size, there is no better place to start for a home brew control HSM class CNC mill. I picked up an early seventies Series II for $850. This had been fiddled with extensively in the control enclosure, but the ways and ball screws are excellent.

John
 
Jim, I had one of those square column mill drills. I think it had maybe 8 hours on it before I sold it. After 2 hours I was pretty dissatisfied. Got one 'hot' project done though, covered the cost of the machine. Marginally acceptable for occasional manual work.

Complete dog for CNC conversion. Qull ass'y stinks. Tons of friction in the bed. Head doesn't track that accurately as z rises. Shallow throat. small usable area.

I sold the mill drill and bought a sweet b'pt series 1 varispeed 9x42 (for $200 more than I sold the m/d!) , added ballscrews, steppers, and a PC.
Bpt only takes up a little more floorspace than the m/d.


I can't speak to the quality of the 8x36, but I felt the m/d from enco was a complete waste of time.
 
Several months (?) ago, a knowledgable forum member wrote about his experiences with one of these mill/drills. (Can't recall the title but the contributor was Joe Michaels.) You might want to search out and read his impressions before pursuing this.

edited to add:

(My experience was about the same as that noted above by damonfg except that my mill/drill was a large round column model - 21 inch. I ran mine for about the same length of time before divesting it.)
 
Don't hold back from a full sized turret mill because of weight alone. You can move it arond the shop easily with a cheapo import pallet jack. Just mount the machine on a platform you can slip the pallet jack forks under. If you're tall you can live with the increased height. Otherwise use a step stool to change tools from - or build a fitted portable stage around the machine.
 
There's quite a bit of info in some of the DIY-CNC groups in Yahoo that would indicate a lot of these square column m/d's have spindles that are out of square with the table in two planes. Like the mini-lathes, etc it appears they're more "kits" than ready to use tools. If you want something smaller than a series I bpt then you might also look for a used Millrite. About the same size and travels as the 8x36 Jet. We've got one here in the shop that my dad bought new for hobby stuff in about 1968. It's had a lot of use, and has been a very good machine.
 
Yes mine was out of square in X and Y. Remedy was to shim the colum where it bolts to the base. Not the best solution, but then again if you are trying to hold a couple of tenths this isn't the machine for you.

Oh the killer was the quill would move when you clamped it in place. Needed a qull DRO, useless without.
 
Not this Ol dusty ass thread again. Well ok, I'll strap on my hip boots and jump in.

Lemme preface by saying I do have other mills (bridgeport cnc, hardinge, bridgeport M headed and a barker)but a comparison is not in order due to the lack a similarities.

I bought the Enco square column mill for the purpose of converting to CNC using the industrial hobbies "kit".

I have ball screws, servos/encoders and will run it via Mach2 through Gecko drives. I am working on a bijur lubrication right now.

I "lapped" the ways for X,Y and Z (Z being the column). The quill will be locked in the uppermost position making it very firm so quill movement will not be an issue. I have r-8 to er-40, er-32 collet holders. I will also convert a manaul rotary table to CNC for the fourth axis (future project).

After a conservative lapping of the ways and an application of way oil friction is minimal. One finger pushes the carriage or table easily (gibs quite tight). Actually friction has changed from abrasive friction to a "wringing affect" friction. The surfaces are matched so well that wringing is taking place causing a certain amount if resistance. But like I said a slow push with a finger and she just glides along.

I am now at the point of setting the column to the base square. If I have to shim the column it's not a problem. Heck I gotta shim my south bend lathe too, just goes with the territory.

I would agree, running the mill manually would be unacceptable, for me. But with a full conversion to CNC it's gonna be a dream. I will completely enclose all the sides with an enclosure (except maybe the top).

You can't throw in statements like too small of a throat, too small of a table, minimal travel. That is just a complicated way of saying the mill is too small for your purposes.

It can't be too small in those areas, it is what it is, it was built that way, it didn't shrink on the boat ride over. All you have to do is check the specs for travel, they are right there just like a bridgeport and larger mill. If it doest meet you requirements then it just doesn't, but the mill wasn't built too small, your job is just too large for this platform.

People will say get a larger mill cause this one is to small. Lemme tell you, the mill they recommend will be too small for someone else, it's that old saying, there is always someone bigger on the block.

I will be creating a web space for the documentation of the conversion as soon as I get frontpage out and running. JRouche
 
Okay true, when I said " Shallow throat. small usable area" it sure didn't shrink in transit.

Just to clarify, the machinable area is small compared to the footprint/floorspace needed for the machine. A knee mill gets you much more machinable area (esp turret mill) for not as much more floorspace.

I am not surprised that the machine would benefit from a healthy lapping and ballscrews. Fit and finish, heard it a million times on the import machine threads.

I don't really want to get into the status of import mill/drills, etc, but I'll gladly chime in on cnc conversions.
 
Danger Will Robinson!!

Before any of you jump on the lapping bandwagon let me (a machinist and machine tool rebuilder of some experience) tell you that lapping the way bearings of machine tool elements is frought with peril. The process that uninformed person (no other word for him) skims through in the link Ben Dis posted is almost completely uncontrolled. Linearity and alignments can be easily lost without the necessary tools and experience to make corrections.

I've done it all and I know what I'm taking about. Hand lapping for geometry, alignment, and linearity is a slower, higher skill level process than hand scraping. Believe me if lapping machine tool elements was all that was necessary to get good fits the machine tool industry would have adpoted it 200 years ago instead of all that laborous hand scraping, fitting, and checking.

So: I BEG you newbies and low budget home shop machinists - do NOT be tempted by plausible sounding fixes until you check into them thoroughly. Glowing stories of apparent success does not translate to axis linearity. If you wish to "accurize" your budget mill drills, get the books, build the skills, accumuate the tooling, and fix your problems with the hand scraper.

Leave the mill/drill lapping kits and one page instruction sheets to the fools and yokels looking for short cuts.

If anyone is insulted by my harsh words, good. You deserve it for not doing your homework and for seeking simplistic solutions in a fool's paradise of naive assumptions and blithe assurances from the ignorant and the hucksters.

[ 02-27-2005, 04:11 PM: Message edited by: Forrest Addy ]
 
Hmmm.... Forrest is right as usual.....and another issue with that page's procedure.....

If you have ever tried to scrape for surface AND perpendicularity at one time....you will have found out it is tricky. One more constraint, but about 4x the hassle, it seems. Maybe I just didn't know what I was doing, but I found it to be much more difficult to get both at once.

He has no clue what he has done to the alinement, because he has no means to check.

To be fair to the guy, though it sounds like
1)he had a problem that had to be fixed.
2)he was not taking much off
3)it sounds like the misalinement from lapping has a 50% chance of being better than the alinement as it was shipped from the factory :D

The thing I would be worried about was not using a "lap". What I got was that he put the grit in and then worked the parts together.

Now, my concern is that it appears he "charged" the parts with abrasive, which will now be working on them forever. Not what I'd want.

I could not follow his material link, it was 404. So maybe he used an abrasive that breaks down and eventually may get washed out. But I don't like the idea.

I'd want to get a piece of soft brass, chew or file it to a fit in the dovetail and charge THAT with the abrasive, then use it on the ways.
 
Lapping the machine ways raised a red flag to me as well. Lapping is accellerated wear. The lapping paricles will most likely embed themselves
into the cast iron ways and continue there work/wear.

Since I know nothing about hand scraping I would try stoning the ways with a 3 cornered stone. At least that would take down the high spots and leave the rest of the surface untouched. That way an ameture could make some improvement and do minimal damage.


I'm tying to touch all the bases before retiring in August. I worry about not finding work for my manual machines later on... Shouldn't worry about it untill it happens.

This has been interesting. Amazing what you guys have to say. An old Bridgeport is looking better all the time.

Jim
 
Forrest Addy wrote: The process that goon (no other word for him) skims through in the link Ben Dis posted is almost completely uncontrolled
Wow Forrest, your ignorance is shinning through, no better "word" huh?

Forrest Addy wrote: I've done it all and I know what I'm taking about.
No doubt, so YOU say.

Forrest Addy wrote: Glowing stories of apparent success does not translate to axis linearity.
You are right, the proof would be in the final machines alignment compared to it's original alignment, remember it's an inexpensive chinese DRILL/Mill.

Forrest Addy wrote: If you wish to "accurize" your budget mill drills, get the books, build the skills, accumuate the tooling, and fix your problems with the hand scraper.
I honestly believe that is bad advise. It takes many years to become proficient with a hand scraper and a certain amount of artistry. A "newbie" could wreck a machine quicker with a mis-guided scraper than with some "soft" abrasive. Yes, soft. The abrasive supplied by industrial hobbies breaks down very quickly. After the first two or three passes the grains have broken down considerably.

Forrest Addy wrote: Leave the mill/drill lapping kits and one page instruction sheets to the fools and yokels looking for short cuts.
You obviously did not take any time looking at his web site. There is a four or five page procedure there. http://industrialhobbies.com/
A little quick on the draw to criticize instead of doing a little research Forrest.

Forrest Addy wrote: If anyone is insulted by my harsh words, good. You deserve it for not doing your homework and for seeking simplistic solutions in a fool's paradise of naive assumptions and blithe assurances from the ignorant and the hucksters.
Yep, a little insulted but more surprised. Your language "goon, idiot, fools and yokels, fool's paradise, naive, blithe assurances, ignorant, hucksters" show me how you think of people you know nothing of, I'm speaking of myself.

You are correct in issuing a caution or even a recommendation to avoid a process which may harm someone or somebodies property. But to blurt scathing descriptions of personalities about people who you have never met (ME) shows me your ignorance.

Keep you knowledge and expert advice relating to machines because you don't have a clue when it comes to judging people. JRouche
 
I have not tried either lapping or scraping so you can take my comments for what they are worth.

1. The process Ben Diss describes is not the same thing as making a telescope mirror concave (which I have done). The telescope mirror is made concave by grinding with it on top of the tool and using a rather large overhang on the strokes. Hence the center of the mirror recieves a lot more action than the edges and wears more. Frankly, I am not at all sure what would happen in the process he describes. The center of the ways would certainly get their full share of the action. But the ends would get additional force (per sq in) as the mating part is slid over the ends, just as the telescope grinding tool, on the bottom, has it's edges reduced more by the overhanging mirror which is becomming concave.

The short, 1" overhang on the strokes may be the best compromise. Or it may be all wrong.

2. Using a fixed stop, wood or otherwise, may also be a mistake. The strokes would need to be somewhat random to pervent a pattern from developing.

I have to agree that he has no idea what shape his ways are now in or what may have been done to the alighment. Hopefully, he did the minimum amount necessary and the changes are not too much. But then, I strongly doubt that inport mills have hand scraped ways. So how good were they to begin with? Perhaps they are better.

3. If I recieved a brand new mill with rust spots on the ways, I would be on the phone in a flash. Enco should have replaced it. P E R I O D.

Paul A.
 
Sorry If I ruffled your feathers Mr Rouche but I do know the hazards of hand lapping and I strongly stated my concerns and contempt the process as applied for good reason. You apparently feel you had success in your particular instance of hand lapping you mill/drill ways but I'd very strongly advise against it for anyone else.

I also know people well enough to understand how rapidly bad advise drives out good in the hearts and minds of the naife. I can just picture a guy frustrated with his HF mill/drill saying: "Lapping! Cool. All that scraping BS seems like a lot of work anyway." These are people (who while well meaning if ignorant) figure if a little bit is OK too much has to be much better.

I'm sorry if you're personally insulted but I felt a very strong statement was important to forestall a rush to disaster. People look to me for advise and counsel in these matters and I try to offer the best I have as I did here in my earlier post. As for years of experience being necessary to be a good scraper hand, yes that's true but a mill drill is a great place to start. I once tuned up a cheap imnport mill/drill X/Y axes with a scraper in an afternoon using nothing more than the the mating parts, a small granite flat, and a couple of measuring pins to check dovetail parallelism.

I'll take it a bit further. A limited amount of hand stoning such as Jim Glass mention in an excellent means of refining fits because the process is controlled and relatively clean. Loose abrasive lapping of way bearings and assembly joints is a good way ruin the very features the operator hopes to correct.

I'll continue to stand by my words: "goon, idiot, fools and yokels, fool's paradise, naive, blithe assurances, ignorant, hucksters" in connection with loose abrasive lapping as a means of correcting gross errors in machine tool linearity, fits and alignments. These words are apt in this case and I use them in the hope they would serve as a deterrant.

If an alleged machine tool rebuilder in a professional shop was caught using a loose abrasive lapping process in fitting machine tool elements or way bearings he'd better have a compelling reason for doing so. If he couldn't, he'd very likely be rolling his tools out to his rig within the hour. Yes that is a firing offense in thse circumstances.
 
Forrest Addy wrote: I'll continue to stand by my words: "goon, idiot, fools and yokels, fool's paradise, naive, blithe assurances, ignorant, hucksters" in connection with loose abrasive lapping as a means of correcting gross errors in machine tool linearity, fits and alignments. These words are apt in this case and I use them in the hope they would serve as a deterrant.
And again you don't bother to read the procedure outlined in the IH web site or my original post.

No where did I imply the lapping was to fix "gross errors" or "fits and alignment" problems. I don't think anyone did, you are the only one who used the words lapping along with gross errors in linearity and alignment problems.

Here, you can read my statement "After a conservative lapping of the ways"
(Definition conservative: Moderate; cautious, restrained in style)

From the IH site: "The goal is to get a nice smooth consistent way travel, DO NOT lap until the every scrape/machine mark, imperfection or whatever you might see is gone. NICE SMOOTH TRAVEL, no more, no less."


With the gibs installed the original machine geometry is established. I have checked the flatness and it has no dishing or concaved structure.

I don't have any problem with someone expressing their opinion (and that's all you have going here. Unless you want to show some results of a regulated test concerning lapping as described by me).

I do have a problem with YOU saying I am the above described "goon, idiot, fools and yokels, fool's paradise, naive, blithe assurances, ignorant, hucksters" which is total BullS**T.

JRouche
 
This is getting pointlessly acrimonious. I'll remove the words "goon" and "idiot" you find offensive if that will please you. Ihe others are apt and will stay.

I didn't attack you personally, Mr Rouche. My object is not to humiliate you but to stop a potential rush to a bad process. You are but the messenger. I attacked the process you advanced and the website you referred to, not you. Yes, I did read the website in its entirety. Yes, I agree that a conservative approach using loose abrasive might possibly lead to good results but only when used very conservativly and then when your luck is good. You must consider: smooth motion obtained by lapping does not guarantee linearity or tracking accuracy.

I'm sorry to play this card but trust me and my many years experience, Mr Rouche. You may hate to concede after publically committed yourself to an untenable position but the faults with loose abrasive lapping of machine tool way bearings and assembly fits are as I have explained. I hate to step on you but I felt it necesary as a means to a greater good.

Over the years many people have retained me paying good money for what I know. On the basis of my suggestions and reccommendations many plant improvement panels have committed millions in their programs of replacement of obsolete machine tools or re-conditioning and retrofitting them with modern productivity features. Here on this message board I'm giving my knowledge away entirely for altruistic reasons. I'd never lead anyone wrong in matters pertaining to my fields of experise.

Loose abrasive lapping of machine tool ways and assembly fits is a bad process when not supported by the appropiate reference equipment, measuring apparatus, systems of checks and inspections, and followed up with high pressure water blasting. Using the same equipment the operator could hand scrape, file, and stone his drill/mill to any degree of accuracy he desires. The job goes much quicker and there is no loose abrasive residue to clean up afterwards.

The loose abrasive lapping technique as shown in the website you advocate is almost uncontrolled by external references and the text is so loosely written it offers ample latitude for the neophyte to screw up a marginal machine into a mess almost unrecoverable except by extensive re-machining. Loose abrasive lapping is a bad process to use in making corrections in fit, linearity, and alignment for machine tool way bearings and assembly joints. It has its place but in in this application.

Take a close look at the website you hold up for admiration, Mr Rouche. It's a classic example of what happens when someone with some writing and graphics talent puts his well-presented and plausible sounding nonsense on a website. "Not all that glisters is gold."
 
To put it bluntly, Forrest knows whereof he speaks....his language may be 'plain' or even a bit 'harsh', but 'tis with good reason....he knows whereof he speaks....

Exactly as Forrest says, there is 'no free lunch' when fitting-up machine tools...i don't pretend to have more than just a small percentage of Forrest's level of knowledge and experience, but, hell, even I know that much....

cheers

Carla
 








 
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