Member postings for Pete

As far into this as your getting Taf, I'd highly recommend doing a search on Youtube for a channel under the name of Jan Sverre Haugjord and go back through some of his past videos. He's got some about scraping a mill much like yours. Sometimes getting another perspective for how to measure and do the three dimensional checks and in the correct order is very helpful. He's taken quite a few scraping classes and knows what he's doing. It's actually quite impressive about the number of machines he's rebuilt back to new or better. For information about scraping and machine tool alignment, it's about the best YT channel I know of.

Scraping a single surface to a high level of accuracy isn't that hard, scraping to get parallelism or machine parts and maintaining the three dimensional alignments takes a different thought process and is multiple times harder. And with a worn but when new a high quality machine, or even a brand new off shore one. The main thing to remember is to trust that nothing might be as it should unless you verify that yourself.

I once bought a brand new off shore 10" x 22" lathe. The very first center drill I tried using with it instantly snapped the drill tip off. Not only was the tail stock bore not on the same elevation as the head stocks center line, it was pointing uphill by about .009" over 2" on the tail stock quill. Add the length of a larger drill chuck and the length of any drill protruding past the chuck jaws, and that fragile drill tip was at least 15-18 thou too high. How that much misalignment was allowed to happen in what would be a production setting and even for a fairly low priced lathe I've yet to figure out. And that was only one of a few other problems I found. After that experiencef, I don't blindly trust anything unless I can verify the manufacturers claims stated or other wise. Although there are some items that are well outside what most of us have available. Vertex rotary tables usually get ok to good reviews on most forums. What I could check on mine definitely showed the table flatness and run out numbers for it's Morse Taper on the included certificate of accuracy not adding up. That to me leaves it's worm and worm wheel accuracy that I can't easily check to be highly suspect.

I think I was a lot more impressed with some of what I have when I understood a whole lot less.

With a knee mill or one with a dovetail column the head moves on, it's much better to have that quill fully retracted for some simple reasons. Extending it out transmits much more leverage on the head due to the machining loads trying to move the head back out of tram. Add the vibrations from cutting and the head can still move even when solidly bolted in place. All 4 of the head bolts on mine are torqued to 45 lb. ft. and I've still had the head move on me over some time. A fully retracted quill is also much more rigid the closer you can get the tool tip doing the work to the spindle bearings. So more accurate dimensions on your parts with less taper due to distortion in the head and spindle, plus a bit better surface finishes. An extended quill and the side loads from something like a larger end mill, then that extra leverage increases the loads on the spindle bearings. And the rear dovetail column mills aren't that rigid. Extend the quill and that leverage problem is going start flexing and bending that column.

That's one reason something like an ER collet chuck is less capable taking very heavy cuts over a Morse Taper or R8 collet. With those the tool itself is a lot closer to those bearings. Industry almost universally uses ER collet chucks because of those tool changers, Or for real rigidity, hydraulic and shrink fit tool holders. The only time I use the quill on my knee mill is when drilling, tapping, reaming or single point boring. Anything else and the quill is retracted and locked and the knee used for any Z axis moves. That's also imo more accurate for precise elevation changes since gravity is always forcing all that weight of the table and knee fully down against the knees feed screw thread flanks so there's no backlash. The only down side is how many times you have to turn the crank handle.

Your bore gauges aren't something I'd known about before and had to Google for a video showing what they looked like and how they measure a bore. No doubt those were very expensive when new. And I'm a bit envious Colin.

The very best de-greaser and cleaner I've found so far would be an electrical contact cleaner. It's extremely thin and will get in where not much else will. But I most definitely wouldn't want it getting into the optical area of those gauges. For where it's safe to use it drys almost instantly and leaves no residue of it's own. But there are some brands that will affect some types of plastics. Most oils will dry out after enough time, but a lot of the causes for issues with metrology equipment is the lack of understanding about how much lubrication is enough. In many cases a single drop of oil is excessive. In a lot of ways the lubrication requirements are much like a fine mechanical watch. As an example, I have a decent Starret indicator bought new about 40 years ago and it's movement started to become sluggish. Pulling it's back off and since all it's inner parts are metal, I just used that contact cleaner to flush it clean. For re-lubrication, A wooden toothpick or even dress makers pin with a less than a drop of oil on the end and lightly touch the rack in a few places. As you use it, the pinion gear will pick up and transfer that minimal amount along the rest of the rack. At that point it was back to working like new again.

In some cases, cleaning and no lubrication would be better than using even a little bit too much. In my opinion using a designated watch and clock oil is likely the best to use. But those bore gauges also appear like there something fairly delicate with no doubt quite complex internals. If it were me, I'd only use that contact cleaner on the measuring end of the tool. Hopefully that will be enough to free them up. Given how I suspect the internals work, there's an internal spring and operating rod to push the measuring tip out. The video I watched really didn't show the finer details. If that shaft can be unscrewed or removed from the body then that may also be where there's congealed lubrication as well. If you can't easily separate that shaft from the tool body, then finding a proper metrology repair shop that has the experience to properly disassemble and clean them would be my next step. Since I've no real knowledge about those bore gauges, I can't be of much help.

That 1/2 function is just a faster and nice to have (when it's working) item. But if the dro is still accurately measuring linear distances. You can still do exactly the same without that 1/2 function. Let's use the Y axis for example, accurately measure your part width, divide that in half. Edge find the part, move over half the distance of your edge finders tip. That puts your spindle center line directly over the part edge. Zero the dro's Y axis, now move over that half distance of the part you previously calculated for it's width. But I'd stress that accurately measure part. Caliper measurements for your part width can't and won't give you the same accuracy as the dro and that half function will. So micrometer measurements would be the better way if your part centering does require that level of accuracy. Analog hand wheel dials obviously haven't any half function either, so you just use the dro in much the same way as you would with those. Yes it will take just a bit longer, and there's a few other ways to do this, but will still allow you to do what you want until your dro issues can be resolved.

I have one of the Blake Co-ax indicators, plus a few spare dial indicators and could easily make my own dual indicator tramming tool. I don't use the Blake for setting the head alignment since it's really not quite as accurate as just sweeping the table with a dti. In fact these co-ax tools seem to have at least a bit more hysteresis over what my dti's do. And in hindsight, I've not found much of anything that the Blake can do that in one way or another a dti can't also do, and with in my opinion better accuracy. It just takes slightly longer. With a short length probe, those co-ax tools are a good way to check the lathe tail stock alignment, if it's being used properly, gravity when checking the vertical elevation has little effect compared to doing the same with a dti. And yes I got fooled by that for a few hours until I figured out what was happening. One of the dual indicator tramming tools would get you close a lot faster for the initial alignment if you ever angle the head for certain jobs and then want it back square. But for my mill, then a simple square against the length of the exposed spindle will do that as well. Then it's time to use that dti. A dial indicator and dti has dozens of uses outside of just tramming the head in with a few shop made additions.

And no matter how accurately you tram the head in, you will always get a certain amount of back cutting with larger diameter tools. That head alignment is also a static setting. The machine itself starts to deflect outside of where you set it once those cutting loads come into effect. Those are just physics and simply because there's always various amounts of machine and tool deflections under load. And the harder the material, deeper the cut, and/or duller the tool, the more you'll have. But head tramming is just one item that has to be checked as being correct. With a knee mill or dovetail column the head moves on, then just how straight is it in a true vertical alignment over it's full travel distance. For any machine tool slide, there's 6 possible directions or combinations that a slide can vary or be twisted. And those misalignment's may not be constant or can even reverse direction over the travel length. Then how square is the tables Y axis to the X axis. Most assume all that is correct, actually checking might surprise a few. Again a few simple tools most already have and a dti can also do that, although a boring head can be helpful as well for checking those knee or column alignments. Fortunately most of those only have to be verified once and then many years later.

Highly accurate machined parts with excellent surface finishes like those are tough enough. Designing your own specialized parts starting with a blank piece of paper or computer screen and making them good looking, functional as well as in proper proportion is something else. Very few in my opinion have that combined set of skills Gray. My best compliment I could use for anyone's work would be to say there as good as anything George Thomas did. I think you've set a new bench mark for what my best compliment would be now.

Have you given any thought about producing a volume II of your Projects For Your Workshop book?

I've bored accurate holes a bit larger than 25 mm with a tiny Emco round column C5 sized mill in steel plate and without a boring head since I didn't have one at the time. I just used a left hand lathe tool with a braised carbide tip that was specially sharpened for the correct clearances in one of the usual fly cutter tool holders, then set my offsets to the increasing sizes with a dial indicator against the end of the tool tip as it was moved in or out by hand. With even a mini mill and a boring head through aluminum, it should be much easier and faster. Mark out and chain drill with the holes almost touching a bit under the finished bore size, knock the slug of waste out ,and then bore to finished size. Rotabroaches, hole saws etc are costly and can only do a single fixed size. And with thicker plate, I've never found any hole saw to work at all well since there not really designed for that type of use. With a small 2" / 50 mm boring head and the proper range of boring bars, you can precision bore any hole size from about .080" on up to a couple of inches even with a mini mill if your careful. With a bit more power and enough torque at lower rpms, the cross hole most boring heads have can be used for even up to 4" - 5" diameter holes in a pinch. Although the depths of cut does have to be reduced at those diameters. I have a much larger mill, industrial level boring heads and bars now, But for anything quite a bit larger than my drills can provide and to speed up the job, I'd still use that chain drilling method. For shops with manual machine tools, it's still a commonly used industrial technique for large precision holes in plate today, and I've seen it done many times. Manual machining is about precision, for larger areas of bulk metal removal prior to that machining, drills and saw cutting will beat any end mill or boring bar out there both in more efficient metal removal rates and tooling costs.

Boring to an accurate size is fairly simple, bore until the hole fully cleans up but still under size, measure and for example lets say it was .030" under. I'd set a .005" offset on the head, bore through and accurately remeasure to see what the tool did for size. Lets say it actually took only .009". I'd then off set the head to take the next cut at .0055" and bore at that setting. Remeasure and lets the say it did take .010". Offset the head a further .0065" and take the last finish cut. Measuring and offsetting the head over or even under, compensates for any tool deflection at a known depth of cut in that particular metal type so it's closely repeatable for the next cut, or even poor inaccurate feed screws and dials. On critical sized holes and even though the feed screws and dials are very good on my BH's, I still prefer setting the last few cuts with an indicator. It's less the about the tool and more about the technique and methods used since tool and bar deflection are always present. Boring with a lathe still requires that measuring and compensation as well. And for high accuracy bearing fits using a lathe or mill, I don't know how else you would guarantee getting any bored hole to a known and close tolerance size without doing so.

Yes your quite correct Gary, and I do know how they work, but while it's technically incorrect, that's the almost universal term most seem to use to differentiate between glass scales and the ball bearing type. Newall does offer actual magnetic tapes now which are designated as magnetic. But my real point was that the Newalls are one of the easiest to mount. So to reiterate, studying what they use should be helpful for anyone who has never mounted dro scales before. My knee scale still required additions just to correct for the column taper, but the rest of it was quite easy.

Anything electrical is just about beyond my knowledge as well Graham. And I don't know if the idea may or may not interest you. But one thing I have learned is most dros today use a fairly narrow range of signal types they operate with. There were a number of others used on the much older dro systems, but a lot of those now seem to have been abandoned. If my information isn't faulty, most of today's dros will use one of about 4 - 6 different signal types. As long as those are the same for both the reader head and the display, plus the number of wires used are the same. Then the plug end can be easily changed over to suit the connection type on the rear of the dro display. For your purposes, then finding something to fit a small mill like that as a complete off the shelf system could be difficult, expensive or impossible as you've found. A display using different scales and reader heads and some well thought out machining on the table or slides to gain some clearance might be the only possible way to do so in a cost effective way. For that machining and knowledge about how and where it could be done without any adverse effects, then imo few would understand that better than yourself.

Yes it was on a Bridgeport with standard sized scales and reader heads. But the ROBRENZE channel on Youtube had a video a few years ago where he mentioned he mounted his X axis scale and head inside the table to eliminate mounting it on the front of rear and have much better protection. Unfortunately he didn't actually detail or show exactly how that was done.

If you've never bought or owned a dro before Benedict it's easy to make a mistake when choosing your scale length to match your machines travels. There not the same thing. The reader head has a length of its own, and depending on where the pick up sensor is located within it, the lengths from each end of the head to where that pick up point is has to be added to your total scale length at each end.The read sensors on mine are in the middle, but I can't say the same would be true for all dro brands and types. In general most of the manufacturers will have line drawings of the scale and reader head dimensions. Checking those before you buy would be time well spent. Crashing a reader head into the fixed end of the scale due to inadequate length usually destroys at least the head.

How you mount the scales and hold them in place may also add a bit more length that might be needed as well. At the professional level of dro's, Newall is regarded as one of the easiest to mount because of the universal kit of mounting brackets and screws that are included. Studying what they use on there website might be very helpful if you have to design and build anything to mount yours to whatever machine you have. Newall dro's use fairly small round magnetic scales , so the rectangular shaped bar scales are of course different. How to mount them in the easiest way possible has still about the same requirements except for that difference in scale profiles. Even then and just to be sure, I'd probably want about 1/4" / 6 mm of spare length at the ends of each scale just to be 100% sure.

With the Evaporust and maybe wire brush treatment, at that point I'd probably use what I have for years Gerry. Made in Germany with the brand name of Simichrome. And probably not too hard to find if your in the UK. With a quick check it looks like Your Amazon UK has it. It's not exactly cheap, but a little goes a long way. Those Sigma gauge stands look to be high quality, the shaft OD and groove should polish up as good or better than factory new. And that polish is pretty gentle so it wouldn't be removing a measurable amount of metal. So far I haven't found anything better than that Simichrome with any metal type unless you go to a whole lot more effort with the felt buffs and industrial polishing compounds that would definitely remove more than you want to. The OD would be most easily done with the shaft in your lathe and that polishing compound on a cloth rag. The groove will be a bit more tedious, but a Dremel or similar rotary tool and the small felt buffs they sell for them, plus that polish is what I think I'd use.

Thanks Michael, not quite what I was thinking or a brand you'd see over here. It's much like the vertical head adjustment on the Quorn. And that design should be easier to set fine adjustments than even the Starrett or Mitutoyo models that have a plain shaft.

I've no idea where that long lead thread would be used, is it on something like a height gauge? But if it's for accurate measurement purposes. Then at the very most, I'd first soak it in a rust remover, then very carefully and gently use maybe a thin fine scotch brite disk (the blue one's are considered to be about 1,000 grit) in something like a Dremel or a verified brass and not brass plated wire brush to remove anything left. Even then I'd still probably oil all of the thread to lessen any cutting action of whatever rotary tooling your using. If it's what I think it might be, then that thread would have been at least precision ground and possibly lapped after. At the levels of accuracy I think it might be manufactured to, you can't be too careful, scratch or alter the thread profile at all. Think about how gentle you'd have to be if it was the thread in a micrometer and do the same.

No fixed steady? Pull your tail stocks handle, dial, feed screw and quill out the casting. Then accurately measure the diameter of the quill bore at the front of the tail stock and the OD of that shaft. Turn up a fairly short nylon or comparable plastic stepped bushing to closely fit both diameters and butt up against the front of the tail stocks casting so it can't be pushed inwards. Oil the shaft well, chuck one end in the head stock and slide the other through that bushing. Low rpm so the plastic doesn't friction melt and rotate it. Obviously you'll have to turn it end for end to get access to all of it. But it should work well enough for the purpose.

Emco produced and sold a couple of different versions of 3 jaw chucks for the Compact 5 designed to fit either your cnc or my manual C5 since they both used the exact same spindle and chuck mounting Michael. So it depends on just which chuck you have. If my memory isn't faulty for what Emco called them? The much more expensive chucks were what they were referred to as heavy duty and noticeably quite a bit thicker than those lighter standard versions. I've no idea if each of those standard or HD chucks used the exact same jaws or not though. And they didn't just have one set of jaws, there were two matched sets for holding larger or smaller parts either by the OD or ID. High precision chuck manufacturing is fairly specialized. So I've always suspected Emco may have had one of the better European chuck manufacturer's produce chucks for all of there lathe sizes and just had there own Emco name added to them. Bison, Rohm or some other manufacturer possibly? And as far as I know, none of the other well known lathe brands produced a smaller sized lathe with that same 3 or 4 cap screws through the chuck mounting system that Emco used on these C5's. But I could also be incorrect. I do remember that chuck mounting design does have it's own German DIN designation, so it is something recognized as a spindle standard.

Even then, I think it would be highly doubtful if you ever found any used jaws that would or could produce the same OEM concentricity without doing a very good job preloading and re-grinding those jaws to work with your own scroll and jaw slots in the chuck body you already have. Mine would do at or under .001" run out at any dimension I checked. So they were very good chucks. There is a small niche business in Europe who sometimes have Emco C5 machines and accessories. Try nielsmachines.com/en He also has a Youtube channel showing anything he has for sale as well as all his older videos. Doing a YT search for the channel name Neils Vrijlandt should find it. Separate chuck jaws could still be quite tough to find even through him, and a complete used chuck would probably be easier. But even good condition and used, any C5 chuck with both sets of jaws won't be exactly cheap since those accessories are now much harder to find and not all that common. And Niels certainly knows that. Fwiw and for pricing reference purposes for anything you might find, just over 30 yrs ago and in Canadian dollars, those HD 3 jaw chucks were right around $450.

Both the manual and cnc C5 also had a 4 jaw scroll chuck that were offered with that same heavy duty designation, again even more expensive (just over $500) than the HD 3 jaw, a lighter semi steel 4 jaw independent chuck, ($125) a cast iron face plate ($65) a ESX 25 collet chuck and collets. Because of the high price, I also suspect those collets might have been manufactured by possibly Schaubin. Although the accuracy of mine certainly reflects what they cost. But making your own face plate or even a ER 25 or larger series collet chuck isn't out of the question. And at that same 30 + years ago time period, the Emco collet chuck and a full set of the collets were almost $900.

Those original single ph C5 motors were also expensive. I had to have mine replaced under warranty and I believe the supplier told me it was around $800. At the time a complete but without any options manual C5 was around $1200. I'm using a VFD to supply 3 ph power to my BP clone mill. Today that really is the best way to go since 3 ph is so much smoother and a VFD allows far better and vastly superior motor control options. It does depend on what you plan on doing with yours though. For the usual part sizes you'd use a lathe of this size for, then a 1/2 HP motor should be fine. I'm also pretty sure Emco's single ph motors used an European metric standard face mounting. But I've no idea if that exact same standard is used on the 3 ph motors as well or not. An industrial electrical supplier should be able to tell you for sure. Most industrial 3 ph motor websites will usually have line drawings giving all the important dimensions, so a bit of research on those would also tell you if you can match the motor shaft size and bolt hole locations to the C5 motor mounting plate and it's drive pulley shaft size.

For diameters of 3"- to it's full 5" capacity and at lower rpm's, then you may still need to drop your depths of cut and feed rates a bit, or just keep and use the step pulleys you have and do a manual belt change like I do with my mill when I want lower rpm and full torque during longer periods of operation that would have less motor cooling. But these are still small and very light weight machines. One thing I can say, my lathe was totally transformed after I bolted it down to a 1" thick X 27" long X 13 1/2" wide or 25 X 685 X 343 mm thick steel plate the full length of the whole lathe and the same width as the chip pan.That added about 95 lbs/ 43 kgs to the lathe and made it much more accurate and quiet. And extremely important, the bed does need to be properly leveled and adjusted until it will cut truly parallel parts the full length of the bed. Not only does any bed twist produce tapers on the parts, but it won't drill on size and will also bore tapered holes. Another addition I'd highly recommend. I believe in the UK there called Bristol Handles? Over here there known as adjustable or ratcheting handles. I bought two metric threaded one's that match the threads Emco used on the C5 tail stock for locking it to the bed and for clamping the quill. That was a great and very user friendly improvement that still looks like something Emco might have have done but didn't.

Edited By Pete on 26/09/2023 01:29:56

Your of course quite correct Duncan, and after you pointed out how I phrased it, I most certainly should have done so in a less confusing way. I meant that for how some think about steel in general. Stronger meaning the ability to resist those bending forces. I should said it doesn't make it stiffer as you did. Hardening to the correct level for the expected use does increase the steels impact and wear resistance so yes in that way it is stronger.

If I was in the same situation you are Margaret, that stud would have been a simple to replace lathe project. I'd do it between centers just to keep everything a bit more concentric. Obviously metric is now the much more prevalent standard in the UK. And whatever the female threads that have been tapped through the top slide for the bottom of the stud you'd of course have to match those. At the top you can cut whatever thread pitch and size is the most standard and available where ever anyone is as long as your lathe is capable of cutting threads in either the metric or imperial pitch you want to use.

Due to the number of various thread standards used over the last 100 plus years, with a lot still in use and some obsolete or almost so today, I'd agree and it can be a bit confusing. I've also read and for various manufacturing purposes, there's over 600 thread sizes, thread forms, pitches, flank angles, root and crest shapes that are common or at least still being used today. And yes having a couple of those different metric, imperial or possibly a few others such as BA depending on exactly what your doing, those thread gauges are almost a requirement for most of us. There's also a fairly easy method of substituting almost any thread pitch standard to something else that is convenient with a online search for the dimensions. Old Model Engineering drawings would be a prime example. Something like those BA threads to metric or imperial, just look up the recommended tap drill size for whatever size and thread pitch is used on the drawing, then find a tap drill chart for the thread pitch standard you want to use for the fine / course thread pitch you have available that would be closely comparable to the drawings tap drill size and just use that. The very small sizes such as 9BA -16BA could be difficult and probably expensive to replicate with either metric of imperial. Think about it this way, any of those metric and imperial thread pitches were standardized for the expected use while still being adequate for strength. Since either still has to do the same job in whatever size and pitch they are, there sizes are quite comparable to each other. Only the diameters, TPI or threads per MM are just slightly different between the two systems. So for what almost any of us are doing, then the substitution method I mentioned will work fine. For very high strength and safety critical items, without question proper engineering data and high grade screws and/or nuts would still be the safest method. And for some such as the Model Engineering 32 and 40 TPI thread series, it's of course not quite as easy. So those might also be necessary. But again it just depends on what your doing.

For myself and in North America, our Machinery's Handbook would be pretty much the usual source for most machining standards. And it has about everything I might need, especially so for threads. I've heard but don't actually know the Zeus black book of standards that seem to be common in the UK and Europe are comparable and possibly even better for some topics. Yes most or maybe all of that information could be found online and for free with enough searching, but it's not convenient or all in one place. And if that Zeus information is anything like what I'm using, then it should greatly simplify anyone's understanding about threads and a whole lot more. Online forum posts or even videos simply can't provide the same amount of detail for obvious reasons.

Thanks for the details about how the belt / motor comes off on the variable speed machines Clive. Overall it sounds not much more involved that what my belt change model is. And that "cuddeble" mode is how I get my head on or off the table. Heavy but manageable if you wrap your arms around it and get the weight in close to your own center of gravity.

It's a fairly common misconception that hardening steel makes it somehow stronger or more resistant to bending, it doesn't. For the same cross sectional area, pretty much all of the more common steel alloys will have the same amount of bending strength hardened or unhardened. Or so close to each other it makes no real measurable difference outside a laboratory test facility. Google Young's Modulus for the lengthy details. As others have mentioned, incorrect levels of hardening would make the steel brittle. I suspect that's what was the cause with your toolmakers clamp File Handle. It's impossible to get very high through hardness levels without it also becoming brittle at the same time. Surface or case hardening does what the terms indicate, the surface layer can be very hard for durability and wear resistance, but the core is much softer and still ductile. Or you can heat treat to a lower level on the hardness scale, a bit less durability and less brittle, but everything is a trade off in engineering and materials. For what we do, toolmaker clamps made from unhardened and ordinary mild steel would be just as strong as something from even Starrett. They just won't be as wear resistant. But I doubt many of us could completely wear out one we made ourselves in a lifetime anyway.

On the better tool maker clamps, then no doubt the drilling and tapping is done before hardening, That hole and the threads would allow the same hardening to happen across and through areas that could be detrimental to the jaw strength and just how brittle it becomes. However they do it during the heat treating process, then no doubt that's something they address so it can't happen. On the much cheaper one's, that's most likely ignored and the steel quality, heat treating etc might well be much more poorly controlled. So in general, there's almost always valid reasons for the higher cost for something that to the eye appears to be exactly the same. But even the best manufacturers can still make the odd quality control mistake. The difference with that and buying new, it would be immediately replaced without any questions.

If you still have enough material left Justin, you could still fly cut that surface even with the raised area just by working to known coordinates from each part edge and using the hand wheel divisions. Trying to sand and polish all that out is going to take a very long time.

I consider end mills as a material removal tool much like a drill is. For larger and flat areas and whenever possible before I bought my face mills, I'd then use a fly cutter as that's what they were always intended for as a tool to remove tool marks while roughing the part out. But I should also mention they are certainly not intended for nor should they ever be used to make large depths of cut. Yes the tool itself can do so, our mill spindle bearings and splines will get damaged after enough of that. Decent face mills can do both roughing and finishing. And the difference between them and a fly cutter, as long as you have at least 2 cutting teeth removing material at the same time during the full rotation, the cutting forces are then loaded against one side of the spindle splines. So they can take those larger depths of cut to the limits of what your mill can do. Just like a two tooth slot mill, it's still a good practice to slow a face mills entry and exit points at each end of the part. But it's the intermittent cutting loads a single tooth cutter produces that starts hammering those spindle splines and bearings to an early death. Watch any Youtube video where there taking large depths of cut with a fly cutter and you can plainly hear that high speed hammering effect if you know what to listen for.

I've set my mill up with a fair amount of tooling to also precision machine hardwoods to closely match metal parts when I need that option. As a test, I spent an extra hour or so one day and got the head on my BP clone trammed in to within .0001" over a 9" circle. Very time consuming, tough and frustrating to accomplish. I then used what's really a 3 tooth 3" diameter face mill for wood. Mine were sold by Wagner in the U.S. at one time and called a Safe T Planer that was originally designed for drill press use. There light years better on a mill and the wood locked in a vise. I made one clean up cut and then a fine finishing pass of .005" depth. Even with that light depth of cut on wood with a Bridgeport clone in almost brand new condition and properly adjusted, there was still clear evidence of the tool taking probably a couple of 10ths off the back side of it's rotation. It's the stack up up all the tiny deflections and clearances within the whole assembly that prevent a clean cut with no back cutting. And the harder the material your cutting and duller the tool, the deeper those back cuts will be. Yes tilting the head a tiny amount can eliminate those back cutting swirls or even slight grooves if chip gets between a tooth and the part face. But your part faces then aren't flat, there slightly dished. That may or may not matter in some cases. While I still get some of that back cutting with my face mills, most times it's happening on a much less used and sharper portion of the cutting tips. If I speed the rotation up a bit and slow the feed rate for those light finishing cuts to dimension. Most times those face mills will still provide a more than acceptable surface finish. I even use my fly cutters sometimes, the sanding and polishing hours they've saved trying to remove any minor tool marks still make them a worth while tool to have.

There's some woods, glues and sealants that continue to produce acidic fumes even after fully curing. Oak is just one of those wood species that does. British or European oak may or may not be different than American, but I haven't checked there exact properties. Part of engineering is understanding the positives and negatives for anything that might be unfamiliar that your using. And yes like it or not, were not immune from having to know about those as well. Fortunately for us, the internet makes doing so fairly easy today. And the more you learn, the easier it is to understand what to look for and how to find it. There's no such thing as the perfect material, everything we have available will have built in compromises involved. About all we can do is chose something that has the least amount of those verses there expected life span and cost against what it's intend for or to do.