You guys are keeping an almost lost art alive. Thank you for all you guys do. You've helped this industrial mechanic become better and more skilled at his job.
Great video! I took my vocational machine classes back in 1983. My instructors wouldn’t let you run a mill until you learned how to square up the head. With technology these days and fixed NC machines. I have to wonder how many young machinist know how to sweep in a head. There is no G code for perfect square... lol Thanks again for sharing! It’s the assumed knowledge that gets lost so easy.
@@usanumba1916 And it's never easy, I been doing it for 50 years, you get better, but it's never just a snap. One thing he did not tell you is always get your side to side with in .002 first ! THEN go after your front to back , makes for much quicker traming to compare side to side to front to back. Front to back can be more difficult then side to side .
Great vid. I just did this to a Bridgeport that has been sitting in the corner of our shop unused for 25 years. The foreman said it can't mill flat. It mills flat now after a cleanup and trammimg. Table was out over 1/16" on the Y and 1/32" in the X. Thanks.
A lot of people have commented on the indicator holder in this video, so I'd like to add my two cents. As a production machinist I find that the fancy ultra-versatile indicator holders aren't always as convenient as you may think. I find that tramming tables and dialing in on existing features makes up a big portion of what I indicate, and having dedicated items to help with that can save time fussing around with arms and knobs. Admittedly, I am the fussy type. If something is adjustable, I tend to fuss with it. The more adjust-ability, the worse I tend to fuss. So K.I.S.S. is my motto. May I suggest if you need an indicator holder: I have a piece of 3/8" round 1018, bent about 100 degrees so that I have a short leg of about 2-1/2" and a long leg of about 7". I chose 3/8" because I have a clamp (from a magnetic base set) that can adjust to hold the shanks of my back plunger, travel dials, and test indicator on one side (3/16"-1/4"), and 3/8" on the other. I use this item about 80% of the time I set up something on a milling machine. You could also put a hole in the end of a rod with a set screw to hold shanks (or crosswise, for that matter), or mill a tiny dovetail into it. Then, just bend as needed (or not, I use straight rods too). I have made a few different holders to do common jobs since any cheap, conveniently workable material will suffice. Holding the short or long leg in a chuck or collet, I can indicate a pretty good range of surfaces, bores and bosses. I really like how the single piece is rigid. I can use it as a handle to spin the spindle: it will return to zero. It may be worth it to conserve time, and you may find that it's nice to have things that are sized for your equipment if you are using hobbyist machine tools.
The bridgeport milling machine is one of the best machines for manufacturing precision parts. I was working for many years when I was young with an equal and when I watch the video I remember those times. Greetings from Spain
Another fine video Don. As a hobbyist I'm still learning, and with all of the fine educators like you and Mr. Pete, Keith Fenner, Keith Ruker, tom Lipton and the many others out there I just keep learning. So Thank You very much for all you do.
I love your teaching. I always wanted to be a machinest. I was 60 yo when i took machining classes at local jr. College. Have had my mill, lathe, and surface grinder for a few years now. Im able to make the things that i want and need to make. But i dont think i have enough years left in my useful working life to qualify as a machinest. But im learning every day. Thanks Don for sharing your knowledge.
Nice demo, I really appreciate that as an experienced professional craftsman you are willing to take the time and effort to make these vids. Also like the old school technique of using a single indicator and adjustable arm on the quill. Did my round ram J-head just the other day, only difference was that I used a Jo block as a portable target so as to to drag the indicator tip across the table. Early on it took me a while to realize that an out of tram head causes mis-alignment of holes when the is a lot of combined quill and knee travel, like starting a deep hole with knee and quill almost to top and finishing with a long boring tool with knee down. Again, I really appreciate that you share your professional knowledge & skills.
Ta daaaa. The channel I've been looking for! I just bought a Alliant that is a knock off of that Bridgeport you're working on. I've never had a mill or have any experience. I have a feeling I'm going to learn a lot from this channel. Thanks guys
Good instruction sir. So many years ago my instructor taught us to use a simple bent 3/8's rod, L shaped, longer the arm the better, and chuck it up in a R8 collet or a drill chuck. Then swing it to tram the head. We could get it within a thousandths
Good man, a point, I always bring my spindle all the way down for maximum accuracy and spread the indicator out to maximum radius, one only needs 3 points, one on each side and one front or back, otherwise the table is off! I get it all within .0005 and I am happy. Loosening 3 bolts well and snugging the last one up, makes it easier to control. Hope this helps?
Not a big deal in this application but maybe interesting to note that the more of an angle one puts on the indicator's nose, the less accurate the read. That after market quill-mounted indicator holder will allow the indicator to setup in a nice horizontal position with less pressure on the nose. Nice videos, keep up the good work.
New at machining I got a Bridgeport Mill and the squaring of the table was my first question. Using the spindle is brilliant. Your video answered all of my questions. Great to see you at the machine and how you finesse the bolts to make micro-adjustments. Thanks so much for your videos and wisdom :)
Helpful video. Thanks for posting. This is the sort of video where I "know" how to do this, but I always like watching others do it. In general, concerning machining, I've pickup up a lot of insight from others set-up and approach. I always strive to improve my own process. In regards to tramming, the mill in the shop where I work only has the head moved 1-2 times a year roughly, so for me, I have done a lot of period checks, but not so much actual adjustment. We are usually in the order of 0.02~0.05mm deviation (under 2 thousandths of an inch).
I set the indicator zero at the back of the table using a small mirror to see the dial, that way you can easily see any deviation after swinging around the indicator to the front of the table when you make your adjustments. For tramming side-to-side, set the zero with indicator at the left side of the table (when facing the mill) and swing it back around to the right side, where the adjustment bolt is.
Have watched many of your videos always enjoy the topic of the day you explain it will and keep it simple to understand. Thank you for sharing Glen does a great job filming and editing. Wouldn't mind hearing him asking any questions that have as he's filming might be the same one we are waiting to ask as we are watching. G W
I use a ground block or spacer and slide it under the indictor when sweeping the table in 90 deg increments because most Bridgeport tables after years of use have nicks and low spots. I also I leave the head bolts snug when Tramming the head Works Great
Machine tool student, I have learned more tips and tricks from your grinding videos than in two quarters, the last three days have seen faster, more accurate work... I'm actually catching up to the whiz kids.
These videos are great! I'm making them mandatory for my staff. Also you sold me on your 1-2-3 blocks, Just ordered a couple of sets for the mills. Keep them coming!
The other trick is to,turn a ring about the same diameter as the width of the table. Thickness dosent matter. Just find a plate chuck it in reversed jaws in the lathe. Chuck it as far out from bottoming on the jaws. . Cut both sides one at a time in the same turning,or chucking. At the end take light cuts slow feed fast spin. Then sand ,sand , sand ,then scotch bright pad till it’s shiny. It will come out as perfectly flat as the slack in the spindle bearings are. Mine came out with a variation of .0002, that’s 2 ten thousands. So that’s perfectly flat for mill work. So then you lightly file the mill table ,lightly to smooth the normal burs. Lay the ring on the table ,,,,and now you can run your indicator around and never worry about the mill slots. An old timer showed me this. You just have to cut your ring perfectly flat. Now 0002 is close enough unless you are at NASA. But a mill needs to be at O both ways ,it’s hard sometimes,but it can be done. You can’t run a mill at anything less than perfectly straight.
Good video Don showing one of the most hateful procedures... LOL Next time try using a 123 block to check under the indicator instead of sweeping the table.. works great. Colin ;-)
Also with most most older Bridgeport's once you bring the knee up or down you can throw your tram/ square off so try to place the knee @ the height you plan to work and don't move it if possible ...
I have a large plate of float glass that I set on the table. Ive miked it and its 0.475 thick within a few tenths all over. Its 18 inches square. I clean everything, lay the glass on the table, and sweep over that. Larger distances get me closer to square. Plus I don't bump the indicator over the tee slots.
The process is called "tramming the head"...Easiest way is making the lockdowns on the pitch and yaw semi-tight, then taking a co-ax indicator locked in the spindle with the back gear engaged and running @ the lowest speed, then gradually adjusting the yaw and pitch screws until you see no movement in the co-ax needle...
If you extended the quill further down and trammed the head in that position would this amplify the error and mean less error if you retracted the quill to it's normal position
I don't quite understand the 15-20 people who continually thumb down Don's videos. Perhaps one of those people can tell me why you dislike this video and others?
Don't know why, though I would guess there is some percentage of 'fat-fingering', 'cat jumped on my lap' false clicks plus "I don't care about machining" people in the wrong place. Don't take it too seriously.
It's great to see highly skilled people like you . When I indicate the head , I actually use gage block so the indicator doesn't bounce off the slots . I love watching your videos. Also I like using magnasine made by you. Even though I'm an employee but like to have good tools or make them . If I can get my hands on the punch grinding and C5 combo would love to have .
You have the right idea with the block, but could use a 123 I wouldn't use a Gage block and risk damaging the finish. I also would recommend looking at a Newbould spin fixture. It will cost more but will be better engineered and made with better materials and be more accurate. My theory is not to waste part of your tolerance with machines or fixtures.
I trammed my mills head within 0.02mm on the table and it resulted in a close call with a cylinder head and a fly cutter...When the backside of the fly cutter reached the head it was cutting 1.5-2mm deeper as the table surface wasn't parallel with the travel...at all! Best thing would be to place a gauge block on the table and move it below the checkpoints but this can still only line up 1 axis and compromises other measurements of the machine!
I have drilled and reamed 5/16" holes for dowel pins that lock my Bridgeport in the perfectly clocked position popping the pins in means everything is nice and square.
This is a good instructive exercise you suggest. You can also move the ram in and out or angled off to one side, or (for a real shocker) move the table way off to one side or the other. On a well made machine in very very good condition you will not have a great deal of variation, but on an older worn machine, or a mediocre quality Pac-rim product, you may be very surprised. One thing I will generally suggest to anyone, besides checking your tram every day (I've known machines to move overnight) make sure to check the tram in the actual position you are going to use the machine, that is, with the slides as close to the position they will be in the actual setup you are about to use them in.
As a quick check you would be surprised how close you can get the mill to orthogonal by simply using a good quality engineers square on the quill shaft I have trimmed the head this way and then swept it with a dti and it was pretty much spot on,roughly thou or two out at ten inches on x and full table on y. In a fast moving environment it s good to take confidence that the head can be quickly clocked to satisfactory with a simple method.
No I'm sorry but I don't settle for more than a thou variation in any direction . You can't expect to produce precision work if there's already such a large error in your machine setup .you really caught me by surprise when you mentioned four or five thou waaaaaaa! Totally agree with your methods though.
“Once you get it done it’s done”. Not true.. depends on what you “hit” or in my case sharing a mill .. what someone else hits and doesn’t say anything. Very frustrating when you’re milling and the head is out but nobody said anything. Or the vise for that matter. You must check both of one is out. He’s right though chase one axis at a time. The larger the end mill you use the more obvious it becomes … a fly cutter is the real obvious one if out. I always keep my mill “dead nuts”…
The way I tram my mill is to use a 12" brake disc that has been ground flat and parallel, and a coaxial indicator. I run the mill at a slow speed and adjust accordingly. I have a video showing this in operation.
Ya know I never understood how to make sure the turret that spins 360 degrees is square or repeatable. Lets say I have a fixture and know its at a know X Y location. If I move the turret how do I get it back to the exact position.
one thing I've always felt that Bridgeports should have is a pin that is drilled and reamed when the machine is new on the knuckle to ram interface. not that the machine should be run with the pin in. but so you can get the knuckle in at least close to start.
Sounds good! Though in imagining having this, the next thing I imagine is finding the shop Bridgeport with the pin sheared off in that (now oval) hole and a trashed worm screw. Because you know someone is going to think "It's stuck!" and try forcing it with the worm screw and then a hand sledge...
I work at a mold building/repair shop and we have a suburban tool radius dresser for our grinding department. do you have a video for how to properly use one?
This is a good way to counter a surface that has a lot of dents, nicks and scratches in it, since you get the average of the register surface, instead of a lot of bouncing in your indicator.
not unless you stone all the defects on the table first! If your table is off, your surface plate will not correct it, your just magnifying the error, stone the table good and use it, put your surface plate in the inspection dept!
Only if the surface plate has additional guarantees beyond "top surface is flat": that the bottom surface is *also* flat and parallel to the top surface. Another concern is that a bump in one spot can now throw the parallelism off.
Lol true. I work with this one guy who always complains about how the head on his prototrak mill isn't dialed in. Even though I dialed it in before he started. At the same time, this is the same guy who can't square up a block
Hi Don, could I ask you if I had something that needed making could you make it for me, I have a blue print of DTI holder that I need making but I just have not the time to make it at work because of work commitments, I am a machinist for an aerospace company with but no time to make this precision holder I acknowledge your work ethics and attention to detail and this is what's needed to make this DTI holder If you can help me we can then discuss details, look forward to your reply Thanks Derrick
Unfortunately I'm not in the business of doing build projects for people, but thank you for contacting me. I wish you luck in your endeavor, and thanks again for watching.
First off , start off by kicking the head completely out BOTH ways side to side AND front to back over a degree on the hach marks, Lets see how to start from being with a totally out of wack head by .100 or more ( as most are when you first walk up to a machine the first time. ) There is a reason I say this.
It would be a waste of time to use a cyl square. And I would not want to risk scraping the bottom of it on the mill table. After tramming Mills a bunch of times you can usually do it pretty fast with the exception of some poorly made ones that are just sloppy loose.
bcbloc02 No, don't do that, you'll ruin the machine by machining a slight convex curve on the entire length of the table. The reason this is not advisable is known as table drop (sag) that occurs when the heavy table is moved to extreme left or right positions. This slight drop is present on all vertical saddle type machines, especially if the machine is old and worn. Tighten up your X gib to minimize this.
Ellie Price Which means if you mill a long piece it will be thin on both ends as the table tips over. Guess you need a mill with outboard supports if you want to do good big work then. Lucky me I have one! :-)
I need help to figure out how to do a milling operation. is there somewhere I can message you? I would appreciate the help so much and thanks for your time in advance.
So “a couple of thousands is not bad??” If I’m off over half a thousand and don’t have access to a grinder, how can I ever machine flat, parallel surfaces?
I want to hear/watch the reaction to the third bolt that was too tight. We're all human...Personally I like to back off my wormscrews after tightening and verify tram.
Making sure the machine is all "true" is good. However, you aren't milling the machine, you are milling a piece of stock. So whether you spend a lot of time "truing" the machine or not the stock is what has to perfect. If one of my machinists spends half the day truing a machine and then believes that is what will make his product perfect, he will be looking for a new job. This video looks like it was made by a school teacher, more concerned about the process than the product. These types of videos and teachers have sold more CNCs than any commercial ever could.
