Hi great video. I am from the USA, Bridgeport mills do have 2 worm screws to adjust the head in both directions. Yes they are very top heavy. It is a very versatile machine.
Happy days, fair play for giving Adam a shout out, love the quality content you both provide, two of my favourite channels ,quality over trash is always a winner in my life, cheers 👍👏🇬🇧
Thanks Stefan, superb graphical illustrations 👍! You are correct that the Bridgeport uses a worm drive on the head tilt, and another on the “nod”. The nod is naturally quite heavy and would be miserable to adjust if the worm drive weren’t there. A handy feature of the Bridgeport is that the spindle sticks out from the quill about 15mm, giving a convenient, cylindric place to clamp on an indicator holder. There’s no need to disturb a tool or swap collets.
I'm very new to this stuff, about 3 weeks into learning "from scratch." What I discovered about the gauge block method is that my mill's table is not "very flat." I ended up massaging the block around for a bit until I found repeatable measurements "within some range." Well my rong-fu 30 is not very accurate. But it is very rewarding to learn how bad it is, and to understand what one can do within the bounds of reasonable badness. It's pretty obvious if you use a brake rotor then you are getting "average badness" that is more under the control of the brake rotor. I guess the idea is to throw everything you have at it and see what comes up.
Great demonstration. The gauge block sweeping trick also works on a Kurt style vise using a drop indicator. I recently mounted a Bridgeport J head on my RF45 clone and tramming with the worm screw is a dream compared to pushing the old gear head around. The trick to dealing with the offset weight is to push in the direction of travel while cranking the worm screw. The worm shaft is fairly small and pushing also helps avoid shearing it.
Nice to have you back (I assume) in the northern hemisphere. I really like the old school graphics:-) I have a Jet clone of a Bridgeport and you're right about the top heavy and the worm drive, etc. It's not a big deal, though. Like you say - put a little friction on the holding screws and tap things around a little. I hadn't thought about sweeping vertically along the spindle. It's over 110mm on mine. That would normally be plenty for what I usually do, but as long as a person's doing a thing like this it's usually worth slowing down just a little and doing it slightly better than you need.
Timely topic Stefan(and Adam), thanks for posting it! Recently took my Lagun knee mill out of tram to make some angled cuts, and need to bring it back into square. I'll give this method a try.
Yeah, Adam's paper cutouts are surprisingly effective didactic material. I actually have been thinking about that. It must be because they are physical objects and you can handle them, point at them. I guess our brains find it easier to process than fancy 3D graphics.
Its such a great aesthetic style with the heavy black outlines, i love it. Its also quicker to do and easier to "animate" than doing it on the PC in Cad or some illustration software.
😂😂 I’ve seen Adam on CNCNYC before but today was the first time I’ve seen his own channel and now Stefen mentions him 😂😂. Love the content, thank you for sharing.
A: a Bridgeport has reference surfaces machined into the quill housing, so that you can hold a square on the table and against the reference surfaces….for rough tramming. B:one of those 2 indicator rigs for tramming is well worth the dough!
Most BP operators forget about or do not know this trick. IMO when manufactured the mills should have two pins that can be inserted to fo a quick alignment. When the head is tightened down remove the pins. Like the alignment pins on the turret of a CNC lathe.
There is something that comes out of what you just explained (collateral benefits). I can look up your technique on the Internet and find a lot of them, but they come up with 'Batteries not included." What I mean is that it's not enough to read this literature, but there is a component that comes from your experience, your way of working, etc., that we can call art and that leads to success
Hi Stefan, I've just checked, there's 756 videos about how to do this ...... Seriously, a big thank you. I'm still very new to all this and I had not thought of the other two ways you showed, not to mention setting an accurate angle. By the way, well done with the CGI - it looks almost hand drawn ......
Fantastic timing Stefan. I actually woke up at 03:00 this morning thinking I really needed to sort out tramming my 45 type milling machine. I have had it 6 months and have still not put time aside to do it fully. Life got in the way.
Stefan, when you made this 11:05 indicator holder a few years ago, you did show how to tram the head. That was one of the main reasons you made the holder, besides indicating bores and such. One of the cool design features of it was the conical joints.
Hey Stefan, thanks for the demo (I admit Adam's post has slipped me). A couple of comments: - the traditional method, indeed, doen't always work on deckel-style machines, since you have no guarantee that the table is also trammed! (the swivel tables or your indexing head could be all over the place). So, better stick to tramming VS travels, like the two other methods. - for the quill method, your Deckel test bar can help, I think it's 300mm long. Though, for the FP1, one could even shorten it a bit, since things are tight there. - for 'Adam's' aproach, the thing to pay attention is symmetry, it's a non symmetric procedure by definition (w.r.t. the X axis). So, the inevitable Z-X rocking can infuence one's measurements if one goes too far (not a big issue with your indexing head setup I suppose). I remember seeing your 'fix a vise on the table and never, ever, move it' some years back (Simon's as well and not only). I admit I feel more confortable with the versatility of the euromill aproach where you take nothing for granted, you just include a couple of minute of tramming (head, table, whatever you need to tram) before working. Cheers, Thanos
The last approaches would work good in tool and die work. Where the part is hanging off of the table and after square cuts, a draft angle has to be cut.
Stefan, the best indicating tip I've seen on your channel is the one where you made up the round piece with a section taken out so that you can pick up an edge on a tilted surface.
3:38 Most don't know that on the Bridgeport there are notches/steps factory milled into the housing at the ends of the quill stop screw specifically for use as reference surfaces for tramming using a square or indicator. On a Bridgeport that would be better than using the side of the quill.
Thank you Stefan for these brilliant techniques. Tramming the mill is a job I hate having to do. I'm sure these ideas will make it a lot easier. Cheers nobbysworkshop
I have Bridgeport clone and it's a pita to tram,there's 20-40 micron change on X when you tighten y and vice versa.topk me about an hour to get within 10 micron last time
I wondered about the moving table being able to 'compensate' (?) for any wear, now I know it does I'll use that method as this is the first time Ive seen it
Thank you for this great video. I understand a 3 axis milling machine as a set of: a table (or any piece support), 3 axis ways, and the spindle. Where each of them needs to be trimmed in two angles respective to it connected component. Or a total of 8 angles to check and adjust. (Being the alignment of the table around the Z axis only useful to have the T slots aligned with X, so probably only 7 are required). Considering this, the two technics of rotating the dial gauge on a flat surface (the table), or moving the table are not equivalent: 1) Moving the dial gauge on a flat surface allows to check the squareness of the spindle against the flat surface. 2) Moving the table allows to check the squareness of the spindle against the X,Y axis. So that if the table is not perfectly aligned to X,Y, the result would not be the same. For example, if the table is not square to the X axis, the created piece will be out of squre (technique 1); while using technique 2 will result in a square piece but worse surface finish, especially with large diameter surfacing tools as only one side will be engaging. Not sure if this makes sense, to be honnest I am not an experienced machinist. Again, thank you for your great videos, I always excited to watch them.
I have a 1943 TREE knee mill. It has a collet closer witch is very nice, no draw bar on a TREE. Unfortunately during a very heavy plunge fly cutting operation. The operator noticed the machine sounded different. We had broke the casting, so now it's "tramed" and welded. No more tilt and nod for me. All I can do now is kick stuff up on a sing bar. In other words it's a glorified drill press. LOL
Thank you master Stefan. Excelent video as usual! I love the Adam-style animations but now I have to go make that indicator holder as I can no longer bear to use my small mag-base Noga indicator holder on the quill.
There are a few subtle differences between the three methods. The first method sets the axis of rotation of the spindle square to the surface of the table, which makes for good fly cutting but introduces inaccuracy if the travel path of the table is not parallel to its surface. The second method sets the surface of the quill parallel to the path of the z axis travel. Two sources of inaccuracy are introduced- that the axis of spindle rotation may not be parallel to the surface of the quill, and that the travel of the Z axis might be out of square to the table surface and table x-axis path. The last method trams the axis of spindle rotation square to the travel path of the table, which generates the best flatness on a surfacing cut, but at the expense of parallelism between the finished surface and the table surface. It seems to me that each method of squaring should be used in specific situations depending on what kind of cut will be made and on which dimension has the tightest tolerances.
The first method (sweeping on the table stationary) will create a unpredictable result for flycutting, since the table surface is not necessary 100% parallel to the axis the table moves on.
When tramming on the table I never swept directly on the table. Slip a solid object with know parallel sides (1) between the indicator tip and the table. Swing the indicator around and check again. Far too many times I've seen the indicator tip take a shock. Another option is to use a good size bearing race large enough to cover the y axis dimension of the table. And sweep on toP if that. Another option is to tram up and down with the quill to a very accurate angle plate in x and y. Additionally the top of the table should mapped to see just how flat the table is to the x and y axis. Also an angle plate should be checked to z axis motion. Head or Knee. 1) As you said a gage block or my personal preference a roller from a Timken type or a cylindrical roller bearing. Ground to within 0.00005"/0.0013mm or less in parallel. I preferred to use the roller out of a bearing for two reasons. One is if I drop it it. The second is I had several sets of 3 made up to different heights for doing set ups. One thing I did a lot of is rebuild machine tool spindles. On a lot of spindles the front face or a gage line are meant to be a certain dimension from a specified feature. This often requires grinding spacers to the needed dimension. These spacers need to be as parallel as possible. Less than .00005" in parallelism. This often required grinding a sacrificial surface to put the spacer on. This gave as true a surface as the grinder could produce.
I wish Bridgeports were so easy to tram, the Bridgeport is so top heavy they have a tendency to move to far and the worm screws are useless for fine adjustments.. I get it close with the worm and tighten the bolts a bit and tap the head true with a lead knocker with the worm set where there's backlash
On the Bridgeport, the addition of the “nod” would make the reading of the quill problematic I’m thinking. I have used a parallel even a set of two. Gauge block tips were good. I always enjoy your videos and learning from your knowledge. Even before you made videos by reading the forums. Thanks for what you do!
Yes the two axis do need to be trammed separately. On Bridgeports and clones the pivot point for the nod is not centered above the axis of rotation. This means that when you tram the nod, you cannot move it half the indicated difference. In fact, if it is very far out, the indicator will be moving the same direction on both ends of the sweep, but it moves much less close to the column than close to the operator. The turret further complicates tramming if you want to use a sine bar to achieve an angle (or compound angle). when you are trying to set an angle other than precisely 90 degrees to the table, the forth and back motion of the ram must be trammed precisely parallel to the y axis, or the indicated angle will be wrong.
Thank you Stefan for sharing this, very useful, especially if you have an older machine with wear to consider. I always enjoy your videos always full of tips to maintain accuracy of the finished work..
Very nice video, Stefan. Thank you. Question: At 8:43 you use a hex wrench that appears to have a feature around the equator of the hex/ball end. Does this feature have some sort of capture mechanism (O-ring, spring, etc) to keep Allen head screws from falling off when gravity is not in your favor? If so, what is the brand of the hex wrench? Thank you.
Thats a Wiha Magic Rin hex wrench - They are supposed to hold the screw, but it only semi-works. And the springsteel rings tend to break. Not a big fan. A piece of blu tack (or equivalent product) works better.
The brake rotor is a great idea... Lap it dead flat and parallel, lay it down and sweep it... I do just have an SUV huge brand new rotor that i took off my mechanic friend as he didnt need it... I dont need it either, but i took it anyway, knowing its a huge fat disc of fresh ground cast iron that i can turn into a lapping plate or some other plate/fixture project... It doesnt beat sweeping the ends of the table, due to wider parameters and gauss principle in a way, but for checking the tram quickly, a sub-micron lapped solid rotor will do marvels... It has over 30cm diameter afterall, so instrument grade surface on it should allow for a nice quick check with a mikrokator... The rotor also has the 5 hole pattern, where two holes are in a line, making it a great way of quick clamping down for such fine readings, and the two small screw holes for rotor retention when the wheel is off make for nice handle places as to not influence the rotor with body temp. transfer... Two file handles with screw in nutserts m6 would provide a great way to handle it for peanuts essentially... Thanks Stefan... You just gave the noblest purpose to an item that was supposed to be trashed as unneeded... A brand new thing woulda seen the shredder just as a written off extra, and now it will be a lab grade instrument for possibly over a hundred years... Its still covered in factory wax...
Stefan, the technic you mentioned on the Deckel style machine do not allow you to trim the head with the table but only align the head with the vertical axis of travel.
Do you have any tricks how to trim the z-movement of a cnc router front/back-wise? I put shims between the blocks of the y-axis rails and the portal, but I think this is not very rigid. Also I can't adjust it later without adjusting everything else as well.
I don't understand: doesn't sweeping a gauge block sitting on a vise simply reproduce whatever imperfections there are in the vise surface? I can see that the total surface area of the gauge block will reduce this effect, but unless you touch off/measure on exactly the same point on the gauge block on both ends of the sweep, any angle introduced by tiny imperfections on the vise surface should be repeated on the top of the gauge block, less a slight averaging effect. What am I missing?
I wonder, how precisely are x, y, z axes perpendicular on a Deckel FP1 machine. I have an old TOS knee mill and I have to devise some method of checking squareness of principal axes - table side-to-side, table back-and-forth, table up-down. Preferably without buying some super precise square measuring block.
As someone that used to do this for a living, having a good square is the right (easiest/only) way to do it. happily a cylindrical square can be found fairly inexpensive. The most important first step thought, is to find the appropriate factory inspection report (ideally the one that came with your machine ). this will tell you how to inspect you machine and how accurate it can be.(short of a major rework of the machine you will never achieve better than the factory). If you dont want to spent on a high quality square you can use use an ok quality square, by placing marks at top and bottom and indicate to these marks while turning the square 180 degrees and splitting the differance. I definately prefered the precision square or cylinder.
table droop is definetly an issue - But not only with that technique, but in general. If you use the table movement method to tram the spindle and you are worried about table droop, move the table symetrical left/right off center, that will average the droop out.
@@StefanGotteswinter Yes. I suppose that the definition of having the head trammed becomes somewhat subjective when the table droops. The best one can expect is a symmetrical bow tie shape on the machined part.
