Vertical (Bridgeport) Milling Machine Head | Every Knob and Lever Explained

this is a typical milling machine today we're going to talk about every knob and lever on the head what it does and how to use it welcome back to cloud 42 i'm james this is every knob and lever where we take a look at a machine and look at every knob and lever talk about what it does and what it's for this is a typical vertical milling machine this particular one is made by precision matthews but there are many manufacturers that make similar machines all patterned after the bridgeport vertical mill now we're going to look at all of the controls on the head today but if you're here for just one thing this video does have chapter marks so you can jump right to what you need of course every machine shop video needs to start with a safety warning this is a powerful machine which makes it very useful but it also means it can hurt you so don't be an idiot let's start with the spindle powertrain of course the whole point of a vertical milling machine is to spin a tool and so it has a motor that runs through a series of belt and gear reductions down to the tool that's held in the spindle now i just have a boring bar in here because it's easy for you to see on video this thing turning the motor is controlled with a selector switch that has three positions stop forward and reverse and it does exactly what you would expect forward spins it forward stop stops it and reverse spins it in reverse for tools and need to run the opposite direction now in addition there is also a brake lever up here and they're in a little bit different position on different mills but every mill like this is going to have a brake lever so if i'm running the mill forward and i want to change direction on this mill i have to actually stop it some mills you can just toggle directly from forward to reverse i've used a three-phase bridge port that you could do that which is great for power tapping on this machine you actually have to use the brake to stop it so if you're running forward go stop pull the brake go to reverse now the brake is also useful for immobilizing the tool for putting a wrench on the drawbar for actually changing the tool this spins freely but if you pull and hold the handle it holds it still makes it easier to change the tool now the speed on this mill is controlled with a variable speed transmission this is a variable width pulley belt drive similar to the transmission in a snowmobile or a golf cart and you change the speed by turning this crank and there's a little readout here on the front that tells you approximately what speed it's turning now you can only adjust this while the spindle is turning so if we put this in forward we can adjust this slower or faster now some machines have step pulleys or you actually have to change the belt some machines will have a variable frequency drive but these crank ones are very common on variable speed mills now because this is actually changing the belt ratio you do get torque multiplication when you run slow the vfd if you run the machine slow you don't get very much additional torque if any but on this kind of a machine if you run it slow you're getting torque multiplication in addition to the speed reduction now if you need to run even slower this machine runs down to about five or six hundred rpm maybe seven or eight hundred practically if you need to run slower than that for a larger tool or if you need more torque this mill is equipped with a back gear press this knob in rotate it around to the rearward position you might need to grab the spindle and twist it in order to get the gears to engage that puts it into bat gear and gives you additional reduction so this can run down on this particular machine down to about 70 rpm now this gives you enormous amounts of torque but the thing to remember is that when you have it in back gear it changes the direction of spindle rotation so if i switch this to forward you can see that the spindle is actually turning backward so if i want to go forward in back gear i have to select reverse and this always bites somebody at some point they put a big drill or an end mill in here and start milling and cannot figure out why it is not cutting properly it's because they forgot and they're probably running the tool backwards and dulling it now the back gear selector lever also has a center position that it will lock into and this is a neutral position so the spindle is free to turn this is really handy if you have like a dial indicator in here and you're trying to center up on a part uh but keep in mind that when it is in neutral the brake is going to have no effect because the brake is connected to the powertrain above the gears for the back gear selector of course now that we've got a spinning tool we need a way to move it vertically now this is commonly used while machining for things like drilling and boring or it's just used to set to a particular height to take a cut and you do that with the quill locked so the quill is locked in position by this lever and all this does is it has a couple of pieces of brass that are milled out to fit against the curved sides of the quill the quill is running in a precision bore and this just squeezes against it to lock it into position when you are milling horizontally you definitely want to have the quill locked now this particular machine has what's called a speed handle on the quill and what that means is that i can take this lever and this you know moves the quill up and down when it's unlocked but if i lock the quill in this position i can also move the lever out and i can rotate this freely without moving the quill so if i have a situation where i'm pulling down i'm trying to drill right here this is inconvenient i can just unlock this move it around and now i have the quill in the position i want and i have the lever in a more convenient convenient space now this is an add-on this did not come with the mill the mill came with a lever that just has a pin that you can sort of pop in and out it's not super convenient so i added this to the mill and these speed levers are available for pretty much every model of mill on the market now if you want to for example drill down to a specific depth and stop this mill has what's called a micrometer death's depth stop there is a scale here and a little micrometer dial here where you can set a hard stop for the quill so when it comes down it hits that position and so if you've got a quill dro or if you're measuring and working uh from touching off and then moving a particular distance you can set up a stop you can adjust this just by turning this little micrometer dial and then there's a lock ring you can screw up against it if you want to stay in position for repeated operations and that gives you the ability like if you're drilling a bunch of holes in the need to go to a certain depth you can set a stop so that you always go and stop at that same depth now this machine like many in its class is equipped with an automatic quill down feed that will allow you to configure the machine so that the quill feeds automatically into the work piece as it's turning you select how far you would like it to advance per revolution and it will mechanically do that for you now this is useful for heavy drilling operations and it's also useful and primarily in fact used for boring where you have a single point tool and a boring head and you want to make a smooth advance down through a bore now when this is engaged and you run the machine the spindle or the quill advances automatically so let's talk about how this works so the first control is the engage and disengage for the quill feed normally this lever would be left in the disengaged forward position so that the entire gear train involved in the quill feed is disconnected from the spindle if you're not using it you really want to leave it in this position so that you're not incurring wear on the mechanism or accidentally getting it engaged when you didn't want it but when you do want to use the quill feed you have to pull this knob and rotate this around to the rearward position and again this is a gear mesh so you might have to grab the tool and rotate it to get the gears to align so with that in the engaged position that sends power from the turning spindle to the gear train to drive the quill feet now to select how far it advances per revolution of the spindle there is another gear selector over here on the side and again you just pull the knob you may have to turn the tool to get the gears to mesh and you can move this to one of three different positions to control how far the spindle excuse me how far the quill moves per revolution and this one there's a lot of gear reduction here so you may have to make multiple revolutions of the tool in the spindle in order to get the gears to engage to change the down feed rate then to control the direction of the feed whether you want the quill to feed downward or upward there is a plunger here in the crank handle here so if you push it in it will feed down if you pull it out it will feed up so i will go ahead and push this in so now we're configured we have the gears engaged we're configured for a specific feed per revolution we are configured for down feed and the last thing we need to do after we unlock the quill you want to do this with the quill unlocked is pull this lever out to engage so if this is just running nothing will happen because the action you the gear train is running through to the handle but the um quill is not actually advancing to actually advance you pull out this lever and it starts advancing when you are done hit that lever and it stops and of course to run the other direction you would pull this plunger out and of course you would start from lower down and go forward and now the quill is moving upward and again you just hit the lever to stop it so if anything goes wrong you just smack the lever now this machine does have an overload clutch so if you actually run this physically into something that will stop it the idea is that the clutch should disengage the feed don't do that yes it's there to save you in the machine but you do not want to test safety features like that now one thing to note is that all of this gearing is ultimately driving through to turn this crank handle which you then engage to drive the quill well if you disengage this mechanism by putting the plunger into the middle position this crank is now free to turn and you can engage the down feed and you can actually fine feed the mill using the handle in fact you can have the power down feed disengaged so none of the gear drive in here is working nothing is connected you've got this in the neutral position and this gives you a way if you want to do a precision down feed either while milling or just to set up the machine you can engage this and then you can use the crank to finally adjust the position of the quill and block it in position for a milling operation or you can actually use this for fine feed for drilling or for fine feed for boring if you want to control it manually instead of using the power feed now what may not be obvious is that the quill feed actually has an automatic stop feature as well what you may have noticed is that this threaded rod that the micrometer stop runs on is actually free to move vertically and the reason for that is because this is tied into a mechanism to automatically stop the quill feed so when this goes down there's a lever in the casting down here that this pushes down and it pushes up on this rod which then disengages the quill feed so if i have this engaged and i am running this manually or under power as the stop comes down here and hits this rod it will push it downward which will push against this lever which will automatically disengage the feed so if i just feed down into it it automatically releases this lever and releases the quill and exactly the same thing will happen if i do that under power now if you're feeding upward there is also a stop at the top if you look up underneath here there is a tiny little button and you can see this little cylinder that moves up and down and inside the casting it's inserted through the hole under the screw cap there's a tiny little barbell shaped lever so that when the stop comes up and actually hits this lever and forces it up that then forces the screw down and so you get the same effect it hits the top that lever forces the screw down which through this lever causes this to to trip and so you can get the exactly the same thing in the up direction feeding upward it'll hit that and it will pop it out now this takes a lot of force and there's a tremendous amount of force on that tiny little barbell in there and it is very common for those to break so you probably don't really want to trust this it's not an adjustable stop in the upward position you probably don't really even want to trust it in the downward position because the manufacturer does not make guarantees about the accuracy on this particular meal precision matthews claims only within a hundred thou a tenth of an inch which is a a pretty wide margin so you really want to feed manually against the position if you have a fixed depth that you want to hit but of course you know that also works if you are feeding under power as well though i personally would never trust that if your life depended on it and if you do want to use it definitely test it manually in neutral first to make sure that it really does function and that is every knob and lever on the milling machine head there are actually some clamp bolts and some worm screws that are used for tilting the head and tramming in the machine but tramming a milling machine is a topic for another day this video is a little bit of an experiment for me if you like this format let me know by giving it a thumbs up down below and leave me a comment let me know what you liked about it let me know what you didn't like about it if you have ideas for topics for future videos throw those down in the comments i'd like to hear them i'd like to hear what you think thank you for watching [Music] you

Channel: Clough42

Views: 52,003

Keywords: EKAL, Every Knob and Lever, Milling Machine, Machine Shop, Milling, Quill, Quill Feed, Spindle, Back Gear, Vertical Mill, Mill, Bridgeport, Precision Matthews, PM-935TV

Id: xrGTV9MnuyA

Length: 16min 23sec (983 seconds)

Published: Sat Jun 18 2022