Mentor says Maximat, little nervous

This forum is dedicated to those hobbyists with the 3-in-1 metalworking machines. Mill-Drill-Lathes. Tips, techniques, modification and use of these machines is topical.

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randyc
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Re: Mentor says Maximat, little nervous

Post by randyc »

Hi Torch,

I wasn't directing my post toward you specifically - this is a recurring discussion with predictable justifications and responses. You happened to be the last person that made claims about a machine that I feel is unsuitable for beginners. The claims may or may not be justified depending on how much time (and scrap) one invests in the learning process.

Regarding the nine-cylinder radial engine made on a mill/drill, sure - why not? As I said, an experienced machinist can produce incredible work on machinery that most novices shouldn't even consider. Afghan village gunsmiths produced accurate replicas of Lee-Enfield rifles 150 years ago with hand tools and a charcoal-fired clay furnace. My point - and I can hardly see how it could be missed - is why handicap yourself when learning (whether it is a cheap Chinese guitar or a cheap Chinese mill/drill) ?

Seems like you are cherry-picking (the welder, for example) and your examples are not typical. You want to make a point, fine. You have a perspective with validity to those who are interested in inexpensive machinery that is readily available and doesn't occupy a lot of volume. From my viewpoint, that's not appropriate advice to those who know just slightly less than you do, LOL.

No offense, you do good work - no VERY good work - for your level of experience ! However others may NOT have your talent, commitment, patience, intuition, math skills and so forth. Therefore you are probably NOT a good mentor for beginning metalworkers that lack those qualifications. Teaching can be effected on multiple levels ... personally, I believe that experience trumps everything. I'd prefer to be taught/advised by one with decades of experience as opposed to one who is ahead of me by only six months or a year.

This is a post seemingly directed at a single person and "Torch" happens to be the "straw-man" for convenience. It is ACTUALLY directed toward those who are newly interested in metalworking and considering purchasing decisions ... who may be guided, for better or worse, by forum information. My previous post noted several personal purchasing errors which should be an indication that there is no animus, LOL.

I ignored the advice of my peers (actually my superiors in experience) and paid the price - several times.

Cheers,
Randy C
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Harold_V
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Re: Mentor says Maximat, little nervous

Post by Harold_V »

Torch wrote: I have played around with Delrin, just enough to see if it can be milled, tapped, etc. Cool stuff, but I never tried to work to a tolerance. I suspect that might be difficult, given the way it cuts.
I'm assuming that your experience left something to be desired.

I have considerable experience machining Delrin, in many cases to exacting tolerances. If you use sharp tooling (read that generous positive rake, with a finely honed edge) it machines beautifully and offers ease in achieving close tolerance dimensions.

The one caveat is that it has considerable internal stress and is prone to extreme movement when being machined. It is desirable to rough completely before doing any finishing----and on rare occasion, rough, semi-finish, then finish.

Harold
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steamin10
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Re: Mentor says Maximat, little nervous

Post by steamin10 »

Randy, Torch: you dont have apples and oranges for opinions in your discusion here. I think your fruit salad is very much on.

Given unlimited money, one can create a machinist playground, with all the pride of ownership that goes with it. That is never the case for a home guy, and speaking for myself, my tool collection is a lifetime hobby, as much as putting them to work. I bought them all cheaply, with a coupla burning mistakes, but all serve to improve my abilities, beyond a hammer.

And owning a Steinway concert grand, doesnt make a musician. It is is skill, knowledge, and practice.

I bid you peace.
Big Dave, former Millwright, Electrician, Environmental conditioning, and back yard Fixxit guy. Now retired, persuing boats, trains, and broken relics.
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korndog
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Re: Mentor says Maximat, little nervous

Post by korndog »

Thanks for all the replies gentlemen
First, let me just say that I am 51 years old and this ain't my first rodeo. I have been involved in many hobbies and businesses over the years that require these kinds of decisions, and they are never cut and dried. The "compromise" tool is a debate that will continue long after I am gone, and it applies to hand tools as well as machinery. The Harbor Freight wild card has changed everything for the time being, and simply cannot be ignored without significant cost. I love fine tools, and that is why I was considering the Maximat for my first piece of home machinery. However, while I explore and search for the killer machine or machines, I have the option of buying a 600 Dollar piece that is somewhat upgradeable and can serve as a secondary machine when I eventually buy a real one. Please note that I do not expect the kind of precision out of this machine that I eventually hope to achieve. That is why I will keep the phone number of old man Jack, the local machinist, tacked on the wall.

KD
Torch
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Re: Mentor says Maximat, little nervous

Post by Torch »

Harold_V wrote: I'm assuming that your experience left something to be desired.

I have considerable experience machining Delrin, in many cases to exacting tolerances. If you use sharp tooling (read that generous positive rake, with a finely honed edge) it machines beautifully and offers ease in achieving close tolerance dimensions.

The one caveat is that it has considerable internal stress and is prone to extreme movement when being machined. It is desirable to rough completely before doing any finishing----and on rare occasion, rough, semi-finish, then finish.

Harold
You are spot on with that assessment. I came across a selection of end-cuts for $20, so I bought it on a whim just to play with it. I have yet to try turning it, I was just milling and drilling somewhat randomly with standard bits and end mills to see how it behaved (they walked right through the stuff). I'll try grinding a lathe bit to a sharp edge and turn a piece, or maybe try fly-cutting it. A future project is to set myself up to resharpen end mills, but to be honest, I've not even thought about how one would go about changing the rake on an end mill.

Speaking of movement when machining Delrin, it seems like it would be subject to compression when clamping it for machining. Is that part of what you refer to?

(I know, wandering off-topic here, but curious minds want to know... :lol: )
korndog
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Re: Mentor says Maximat, little nervous

Post by korndog »

Curious, is it common on this forum for people to indulge themselves with off-topic private conversations? Just wondering.
korndog
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Re: Mentor says Maximat, little nervous

Post by korndog »

Curious, is it common on this forum for people to indulge themselves with off-topic private conversations? Just wondering. :)

By the way; just kidding....indulge all you want. appreciate the help.
Torch
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Re: Mentor says Maximat, little nervous

Post by Torch »

randyc wrote:I wasn't directing my post toward you specifically - this is a recurring discussion with predictable justifications and responses.
That's fine -- I volunteered to play the Devil's Advocate. I don't take any of this as a personal attack or anything, I think it's a healthy debate that will help anyone considering the issues.
You happened to be the last person that made claims about a machine that I feel is unsuitable for beginners. The claims may or may not be justified depending on how much time (and scrap) one invests in the learning process.
Unfortunately, this is can turn into a bit of a "Which came first, the chicken or the egg?" conundrum. The Afghani gunsmith obviously didn't learn on a Bridgeport and then progress to a vice and file. Is a part of the attitude towards the 3-in-1 amongst professional machinists due in part to the comparative ease of use, power and rigidity of a dedicated mill? Could some people simply be trying to work outside the machine's capability envelope, so they believe the machine is inadequate? As a home hobbyist, I have the time to take 30 thou cuts if necessary, but a professional has to crank out the work promptly and efficiently. As such, I have demonstrated that the machine is actually capable of producing work to pretty decent tolerances, even if it does take longer. As for my aptitude, I think you may be giving me more credit than I am due. Consider our Afghani friend again: think what could he accomplish if he suddenly acquired a 3-in-1! Is there any reason to suspect that a North American, also stepping up from the file-and-grinder level, could do less?

My point is not that a 3-in-1 can take the place of separate machines in a professional environment, but that they are a worthwhile consideration for that segment of hobbyists that would otherwise be looking at other hobbyist-grade equipment like mini-mills and lathes.
Seems like you are cherry-picking (the welder, for example) and your examples are not typical. You want to make a point, fine. You have a perspective with validity to those who are interested in inexpensive machinery that is readily available and doesn't occupy a lot of volume. From my viewpoint, that's not appropriate advice to those who know just slightly less than you do, LOL.
Actually, my point was that any manufacturer can crank out a lemon from time to time -- even Miller. Consider this: you had a bad experience with an unspecified brand of mill-drill from an unspecified source an unspecified number of years ago. Maybe you got the lemon, maybe they were all lemons at that time, maybe that particular brand had no concept of "quality control". To label all 3-in-1 machines as lemons because they share some features in common with your mill-drill is not necessarily appropriate. The Maximat has a decent reputation for quality and to condemn it on the basis of the 3-in-1 format is like condemning all MIG welders on the basis of experience with a cheap Chinese (or Mexican) knock-off.

That is not to say that your experience should be disregarded -- far from it! "All knowlege is learning and therefore good" as my brother would say. However, as Devil's Advocate, it is my job to present the other side of the story so that the OP (and others) can arrive at their own decision based on their own needs. :wink:
randyc
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Re: Mentor says Maximat, little nervous

Post by randyc »

Hi Torch,

Fair enough - there's adequate space for any number of opinions regarding this topic and I've read quite a few over the years. The forum of which I have been a member longest (PM) no longer allows discussion of these machines, as I recall, because the "debates" became overheated, LOL.

In the previous post, I wrote in general terms - that's probably poor practice because readers are not presented with specific problems, examples that they might encounter. Let me elaborate a little:

The mill/drill that I purchased wasn't a lemon, it was just a mill/drill with all of the limitations of the design. I found that the head HAD to be moved frequently, despite careful planning. It's not practical to use a mill/drill for many common operations, for example: side milling with a small end mill followed by drilling and reaming. It only requires a few seconds thought to realize that the quill can't possibly move the amount that most chucking reamer shanks require after being first set up for milling.

In fact, installing the R-8 drill chuck requires four or five inches of space between workpiece and spindle, the R-8 boring head requires about seven inches - more with a boring tool installed. How can one plan for an operation that requires side milling followed by either of these tools when the machine has only four or five inches of quill travel? (And as previously noted, the poor practise of imposing heavy side loads when the quill is extended.)

I made several mechanisms, attempting to alleviate alignment problems, including a mirrored-laser indicator (not practical because of temperature variations) and a 150 pound welded support that tied the base of the mill/drill to the top of the column. A split-clamp, attached to the head, was intended to keep the head aligned as I cranked it up/down. The best alignment I saw was about .030 without fine-tuning at every position.

Head alignment with an indicator or edge finder was frequently impractical - using the chucking reamer example, the head would have to be about ten inches away from the work. It's not easy to accurately reach and indicate from that distance and edge finders are clearly impractical. If one does only very small work and doesn't do much boring or reaming (maybe even drilling), then perhaps a plan could be devised to work within the limits of the machine. Or maybe one could build a ten-inch-high "toolmaker's chair", LOL. ( A "toolmaker's chair" is a small, precisely-ground setup aid that allows an indicator to accurately locate two edges of a workpiece.)

For my needs, and despite my motivation to make it work (I wasn't thrilled about paying shipping costs to send it back and listening to the "I told you so's"), the mill/drill was a total bust. I swallowed my pride, ponied up the shipping costs, spent three times the money for a vertical mill and re-arranged my shop to make it fit. The vertical mill that I bought on paper, has a smaller working envelope than the mill drill. Practically speaking, it has four times the work envelope if one takes into account the verifiable accuracy of the two machines when working at their limits.

Frankly there are times that I wish for MORE than the 20 inches clearance between spindle and table that is the limit of my 8 x 30 vertical mill. I didn't have the mill/drill long enough to realize that it's unlikely that it would ever have been functional with my rotary table + 4-jaw chuck mounted, along with a boring tool or a chucking reamer ... The work envelope of these machines seems impressive but they are second-operations machines and that's about the only way that the work envelope can be effectively utilized without moving the head.

In any event, thanks for taking my post as it was intended rather than becoming defensive. These forums are only constructive when the discussion is dispassionate.

Cheers,
Randy C
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Harold_V
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Re: Mentor says Maximat, little nervous

Post by Harold_V »

Torch wrote: I've not even thought about how one would go about changing the rake on an end mill.
Without the ability to grind the flute, you can't, and don't. Modern CNC cutter grinders are capable, whereas manual cutter grinders are not generally so equipped.
Regrinding end mills is a great idea, but consider the geometry of such tools when it comes time to re-grind. Because rake is formed by the flute, as you move the cutting edge towards center, rake angle changes. Small end mills quickly go from positive to negative, whereas larger diameter end mills do so much slower. However, in all cases, their is a finite amount that can be removed before the end mill loses its ability to perform well, due to rake moving towards negative, and the loss of chip clearance. Note that it is generally a waste of time to regrind end mills ¼" in diameter, and smaller. With those, pushing the end back is generally the best idea, so you retain the original rake and chip relief. The end is often dull or chipped, while the balance of the flute remains in good condition.
Speaking of movement when machining Delrin, it seems like it would be subject to compression when clamping it for machining. Is that part of what you refer to?
No, although that can be a consideration. The problem of which I speak can be seen easily by various operations. For example, if you remove material from one side of flat Delrin, the piece will bow considerably. That condition can be controlled by removing small amounts of stock alternately from both faces, or, you can remove material randomly, leaving enough material to take finish cuts. The smaller the cut, the less movement. The same conditions prevail when turning, although, because material is removed from the entire surface (under normal operations), movement may not be as evident. Interestingly, it was a lathe operation that gave me cause to rough, semi-finish, then finish. The part in question, shown below, is an extendable blow pipe for bagpipes. Roughing the exterior yielded as much as 1/8" movement, so the exterior was rough turned, then semi-finished, before the bore was drilled. Final contour and profile was accomplished as a last operation, at which time the material appeared to be quite stable.

The problem is no different from working with cold rolled steel, just more pronounced.

Harold
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ken572
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Re: Mentor says Maximat, little nervous

Post by ken572 »

Hey Guy's,

Another neat thing you can do to save time and money with Delrin and many other plastic's
is spin weld two parts together. Chuck up the larger piece in the lathe and with the smaller
piece turned about .007" to.010" bigger then the ID of the big piece you hold it into the
big piece and crank it in with the tail stock. Perfect pressure rated weld every time. :wink:

Even works with a 3 in 1 :lol:

Ken.
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The best learning experiences come
from working with the older Masters.
Ken.
Torch
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Re: Mentor says Maximat, little nervous

Post by Torch »

randyc wrote:I made several mechanisms, attempting to alleviate alignment problems, including a mirrored-laser indicator (not practical because of temperature variations) and a 150 pound welded support that tied the base of the mill/drill to the top of the column. A split-clamp, attached to the head, was intended to keep the head aligned as I cranked it up/down. The best alignment I saw was about .030 without fine-tuning at every position.
I have read about a number of interesting solutions to the problem. One fellow simply mounted a laser pointer to the head, pointed at an opposite wall were he has a line scribed. Of course, the accuracy of that depends on the accuracy of his line. Another fellow milled a v-groove in the column and installed a mating piece in the casting, adjusted by a set screw -- kind of like a gib. Apparently, that is extremely effective, but of course requires access to another milling machine or fabricating a whole new column. Personally, I have so far just treated it as if I had removed the work from the table -- re-reference from a common point and then zero out the DRO. My DRO has a feature that allows up to 200 points to be set, relative to another point. So re-zeroing the reference point brings all the saved points back into line. (I'm sure Harold would say I'm cheating, but it sure is convenient :lol: ).

I know what you mean about the edge finder -- it's not always possible to use one for this task, requiring a bit of ingenuity to get things right. For example, it can be possible to use a virtual reference point. Take your boring example: Let's say you drilled a starter hole with a drill bit, then had to raise the column to accommodate the boring head. You are absolutely correct that the edge finder is not long enough to reach. However, if you first measure how much the drill bit wandered off centre (using an edge finder and the DRO or sweeping the hole with a DTI in the chuck or other technique) before raising the head, you can then raise the column, set the boring head to 0 (verified with a DTI) and then centre the boring head (using a piece of drill rod and feeler gauges, or sweeping the hole with a DTI or other technique) and then correcting the location by the previously measured offset. There is no question that this is more time consuming and less convenient than simply cranking a knee up or down, but it is possible. One of the fellows here (Jose, I think?) has the tag line "There are no problems, only solutions. " In a production environment, such delays would be inexcusable. The home hobbyist tends to be more tolerant about time constraints. I personally go out to the garage to play and can fiddle around for hours without realizing it. (SWMBO came out the other day and mounted a clock on the wall directly behind the machine, where I can't miss it :lol: )
In any event, thanks for taking my post as it was intended rather than becoming defensive. These forums are only constructive when the discussion is dispassionate.
The written word does not convey body language, and different people have different ways of expressing things. Too often these sorts of internet discussions can be misunderstood and someone takes offense (I saw the effect best described on an international motorcycle forum as "we are 3 continents separated by a common language" :lol: ). Rest assured that I do not take offense easily -- call me anything you like, as long as it's not "late for dinner". :wink:
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