Hollow Chisel Mortiser Tips and Tricks

hi i'm rob cosman welcome to my shop the first time someone told me they had a drill press i would drill a square hole thought they were joking until i actually saw it a hollow chisel mortiser the best way to drill a lot of mortises if you're interested i'm going to walk you through the process of setting it up sharpening it and using it stay with us i'm rob cosman and welcome to my shop we make it our job to help take your woodworking to the next level if you're new and you haven't subscribed please do so hit the notification bell so you'll receive alerts when we release a new video and anytime we use a special tool we'll always leave a description down below alright let's get to work so this is called a hollow chisel mortiser this is actually probably the smallest example if you look over here i've got a much bigger foot operated one that i'm in the process of restoring but quite frank i've used this for the last 35 years and i've it's only been a few times that i've found it underpowered so what it does in a nutshell it's a chisel hence the hollow chisel this one is half by half that has a drill in the middle and as you apply downward pressure this just barely clears the inside so as this is drilling a hole and you apply downward pressure these points cut or establish the outside perimeter of the mortise and as the material is pushed toward the middle the drill carries it up and out and that's the way it goes so you've got a few adjustments you can move your fence in and out you this is a a guard or a hold fast that keeps your piece from pulling the board up with it so when you make the cut it's a fairly a very close fit actually so when you go to bring this up out of the hole if it wasn't holding being held down by this hold fast then you'd have a hard time getting that out of there you've got quite a bit of leverage in order to apply the amount of downward pressure you've got a stop over here that prevents so that you can set how deep you want to go and if you're not going to see the bottom of the mortise i always cut it deeper than i have to just to avoid having to clean up the very bottom there's several distance different sizes i've got i guess i only have three for this but you can buy others so i've got quarter three eighths and half which would be the most common sizes anyway and the downside to this one is that it turns really fast so the rpm is 3 450 but it's only a half horsepower motor so you get using a half inch by half inch drill or chisel in a piece of hardwood you're gonna find some problems however for most work in three quarter size stock we're using a quarter inch mortise it works great great so let me walk you through exactly how to use it what to look for and more importantly how to sharpen and maintain that chisel so the first question to ask is do you need one well this is not very expensive um i think at the time i bought this it wasn't more than 300 doesn't take up a lot of floor space in fact this is just an extra stand so all that you actually buy is from here up it comes with the chisels so there wasn't a huge expense you can buy additional ones if you're going to cut if i was going to do one door one cabinet door and i was going to chop and have mortises on all four corners i probably would do it by hand if i was going to do three or four doors i could probably justify buying one of these but remember now this only does half of the joint you've got to cut the tenon but being able to go in and chop that mortise as fast as this works is a real plus so i would consider this to be if you're going to be building house furniture i would invest in one of these without a without a second thought there's lots of different brands they're all about the same size what you want to make sure is this you don't you want this head to travel on that uh big frame on the back so there's very little run out there's a if you look on here there's a gear inside of here so you've got a toothed rail right there and you've got a gear inside of here you've got a long leverage arm which is probably 18 16 inches long so you get a lot of torque on that you can adjust it so that you're always pulling in the most advantageous angle you wouldn't want to have it sitting way down here depending on how deep you're chopping the fact that you can take some of the play out of it if there is any is a real plus so i can't buy the delta one anymore i don't think but i thought it was of the ones that were available at the time i bought mine i thought this was a good one the fence you can add whatever you need to to the fence it's not that difficult the bigger models actually have a table that will move so that you chop and then the entire table moves instead of having to push this along but i've never had a problem holding that just with hand pressure alone there's nothing pushing it this way or that way so as long as you can hold your thumb against this and squeeze it against the fence i've never had an issue one of the biggest jobs i ever did with this i had a uh i had a commission to replace all the dining hall furniture for a private school it was seating for 200. so i made essentially 200 chair 200 maple chairs and there was one two three four five six six uh half by half inch wide by anywhere from two to six inch long mortises and that was in hard maple and i did it all with this so it certainly would stand up to it however it was really aggravating when that little chisel would get jammed up and it would literally stall this motor so if i was looking for a new one or another one today i'd look at this horsepower rating and i'd want to get three or three quarter horse or maybe even one horse and i would sacrifice the rpm that being 3450 the other speed would be 17 1750. i would go down to 1750 which would give you a little more torque you're spinning that fast with a half horsepower motor you don't have a whole lot of torque so that would be the that's my only criticism as far as i didn't show you in here but you you simply you have a chuck key that allows you to release the chisel you've got a set screw over here that allows you to release pardon me the chuck key releases the drill bit the allen wrench releases the chisel there's a fair bit to setting it up to getting it so that the sides of the chisel are either perpendicular to the fence or parallels depending measuring from the backside i'll show you a couple of tips on how i did that um what else about it as far as the adjustments down here as long as it can be locked so that's good and rigid and doesn't move i don't think there's a whole lot else so for for an inexpensive hollow chisel mortiser i think this was a good choice i'm sure you can find them used but this is a delta model number 14 650. okay i took everything apart we're starting from scratch we're going to build a door now we're going to put the frame together so this is my style this is the part that runs or vertically this is my rail that runs horizontally so the first thing we need to do is establish where we're going to put our joint so just get some rough dimensions so there's where the the bottom of the rail is going to be now we want to have as much as possible but if we get too close out here we just don't have enough strength so i'm going to suggest we're going to want to leave at least that much up on this end so i'm going to put a line there and we want a little bit of a shoulder you don't never want to have the tenon going right into the mortise and having it right at the bottom of of this rail because just the fit's not going to be there and you're going to see a bit of a gap so you always want to have a bit of a shoulder which means i would leave just about that much to allow the cover for this to cover all the way around that mortise so if this is the end of the rail then let's come in right here so we're going to run our mortise from this line to this line so we're going to go over we're going to set up the chisel we're going to set up the fence and we'll actually run this and what we didn't determine yet is the depth but we'll work on that in just a second so the first thing i need to do is lock this in place and then put the the drill in but i want to make sure that that drill or pardon me that chisel is going to be this back face is going to be parallel to the to the fence if we don't when we go ahead and we drill a series of holes they could be off like this i'm going to exaggerate it imagine having a bunch of square holes like that that you're trying to create a nice big long mortise you want one to overlap the next and have a nice continuous uninterrupted line on both sides your gluing face is going to be this one and this one so the smoother that transition is between the chops the better and we're dealing with a very small chisel and most of your work is going to be with a quarter inch certainly 85 percent of what you're going to do is in three-quarter stock and if you're cutting a mortise and three-quarter stock you're typically going to be cutting a quarter inch mortise which gives you a quarter of an inch on either side of that and that's your best bet for maintaining the maximum amount of strength out of the joint so third third and a third okay so what we're going to do is i want to somehow extend that so i'm going to take a magnet and a steel rule i'm going to attach that but i'm going to put this in first and both have to go at the same time we just aren't going to set the the drill up actually we can actually probably might be able to put that up afterwards but sometimes they're too long so i'm gonna put it up in there right now i'll just snug it up enough to hold it in place now i want i want that shoulder to be right up tight there's a lot of force in the chisel so you don't want to have there's a shoulder on this you don't want to have that sitting down lower and allow that to move so i'll put that in place i'm going to bring this fence out lock it i'm going to bring this down got to get these up out of the way now that was big enough you might be able to just put this up against the fence and tell but i want to be a little more precise in that so what i'm going to do is i'm going to attach that like so and then i can look down here and i'm going to measure from the extremes of that rule the fence is locked in place so i know that's exactly where it's going to be but we can tell that we're out we're out of whack right now so i'll do that by eye first okay let's see what we got so we've got 9 16 on that side we've got a half inch on that side so we got to move that just above just too much okay that's just a strong half inch and so is that so there we go easiest way to do it lock that tight and we can take this away okay now we need we don't want we don't if it drills out too far it may wander if it's up in too tight and it's rubbing against the chisel when it spins it's going to create a lot of friction and this thing will be blue in no time so we want just enough clearance that we don't experience either one of those examples i just gave you now i'm going to i'm going to loosen this up let that drop freely so just got it jammed up in there so there's where it's making contact so i'm going to just drop that down a little bit and i hate to be so imprecise in saying something like a little bit but you'll get a feel for it okay not making contact not sticking down too far i think that's probably good so we'll snug that up good and tight and we can close those now let's determine how deep we want to go the deeper the mortise the weaker this is going to be because you're removing too much of the material so i'm going to suggest that we go uh maybe right about there so if we're going to go down that far the problem is at the bottom you're going to get a lot of mess it doesn't cut a nice squish nice clean bottomed hole so what i'm going to do is i'm going to bring the chisel down probably to about there and that's going to make it so all i have to do is take a mortise chisel and just give it a little scrape on the bottom to get rid of the loose stuff but my will easily be able to have my tenon come in to this distance got a little extra room there for glue to get and i won't have to as i mentioned go in and actually make that perfectly flat bottom you got to remember you're with if you made a perfect flat bottom and some people worry about this what you're doing is you're gluing the end of the tenon to a long grain surface but you've got an end grain surface going to a long grain surface you're not gaining any glue strains whatsoever so the only important glue surface is going to be the sides the the sides of the mortise and the sides of the tenon that's where you want it to be a very close fit so what i'll do is simply drop this down to that point right there now over here i've got a rod that runs up and down and there's a set screw there's a set screw holding it so i'm going to drop that until that rod touches the bottom and then lock it in place now i want good leverage when i'm when i'm applying downward pressure with this so i'm going to move it up one notch that means i'm going to be chopping like that that's nice and convenient okay next thing we want to do is we want to get this centered so my first thing to do is come in here and establish the center so this is three quarters of an inch thick so 3 8 of an inch is going to be my center point so i'm going to use the point of the drill i'll loosen the fence i'm going to make a couple of guesses first before i'm not going to actually put it right on that dot because once i mess it up i won't be able to use it if i need to fine tune it now and looking at that i can tell that i need to i need the fence to go back a little bit more best to snug that up each time by the way okay that's a lot closer so what i'm going to do is i'm going to come over here away from that dot i'm going to make a mark and i'm going to turn this around so i'm referencing from the other side i'm going to see if those two points line up yeah that's close but not quite got to move it back just a little tiny bit let's try that again okay they went in the same hole so i'm perfectly centered okay now as i mentioned we want to keep this from popping up when we retract the chisel so we want these we want this whatever you want to call it this hold fast or hold down to be sitting right on top need to be able to move it so i'm going to come up just a little bit off of there and by the way if you need to if you need more capacity i've taken this off turned it around and give you an extra half inch or so okay i'm going to work this way so i've got clearance underneath very little very little room for that to move you want to be really careful when you're doing this you don't want that chisel to and pulling it out to get yanked off sideways it's easy to break at the same time you also have to be careful when you're doing your chops you don't want to do a part of hole so here's what i mean these are my two extremes i'm actually draw a line on here so i can follow it so i'm going from line to line so what i prefer to do is make my first chop out here make my next chop out here so i've established my outside edges i've got the wood all the way around the chisel so there's no reason why that chisel is going to want to slide one way or the other there's a mount same amount of resistance all the way around if i were to make my next chop here i would have i would have wood pressure on this side wood pressure on that side would pressure on this side i have a opening here and that chisel is going to want to follow the path of this resistance it's going to have a tendency to want to wander off this way and you run the risk of it not all not only creating an inaccurate hole but it may very well bend over enough to break so what we're going to do i can just line that up by eye now if you wanted to and you had a lot of these to do you could put some marks on here i've added a wooden fence to the metal fence so you could easily change that but i can in easily eyeball the side of that chisel with that line and go all the way down and by the way this gets hot and it's the shavings coming out of there to help to keep it cool so you you'll develop a feel for what the appropriate speed is but you don't want to go too slow or it'll get cooked you already want to go too fast because again you're dealing with a small chisel you push it too fast particularly in hardwood you may have a 10 you may have a tendency for it to run one way or the other now on this one i'm eyeballing the right side of the chisel lining it up with that line going down and making my chop now i'm going to come so that i have a little bit less than a full chisel width away from this last hole make my cut same thing okay this one actually i'm gonna split the difference i'm going to go in the middle between there and i'll show you why okay so here's what i have i've got four holes now i've got to get rid of this material in between i want to make my next chop so that there's wood resistance on this side wood resistance on that side but there's no wood resistance on either the left or the right so there's no reason for that chisel to want to wander one way or the other i'm going to try to go right down the middle of that hole apart me i'm going to try to go right down the middle of that last section move it over and do the same thing and one last one now if this screeches on you you know you've got that drill a little too tight a little too far up into the chisel and it's making contact but that that sounded and and worked perfectly now let's have a look at that so you can see for some reason they can't seem to make these hollow chisels so that you get the blade the drill is perfectly centered you always seem to find that the drill is going to run out a little bit on one of the three outside edges of the chisel in this case it's running out a little bit more over here whereas that's a nice clean side so if you look down in there that's a pretty clean mortise there's a little bit of debris in there okay so if you look really closely you will see that there's some debris right here that didn't get cut so i don't have a nice clean mortise all the way to the bottom but that's all right because i purposely cut it deeper than what i need my tenon is going to stop short of that little ridge right there if i need it to i'd go in with a chisel and clean it out but i'm not losing anything by making it just a little bit deeper so lesson to be learned on this one cut a little bit deeper than you need most importantly is you've got to line that chisel up so it is perfectly parallel with your fence so that you don't get those overlap marks okay let's sharpen the drill bit first or at least look at it so there's three things that you may need to fix this is the cutting lip that does the cleaning out the bottom so you're going to sharpen that surface right there if it needs this is the lip that does the scoring on the outside so you're going to sharpen that face right there if it needs and that's the point that keeps everything centered hopefully you don't have to touch that but if it gets damaged it means going in and taking equal amounts off of those three sides to keep these edges nice and sharp so they do a little bit of cutting and to keep that center point on center so most likely the only two that you're gonna have to work with is this cutting lip out here and this scoring lip right there so if you put this in a vise i prefer not to use my bench vise but i'm going to have to today i always like to have some magnification so i can see what i'm doing so you're going to want to file i've got a safe edge right here so i don't worry about cutting down in and i always like to paint that i'm going to do that again if you paint it with a felt tip marker then you know exactly where you've made contact so i've got to lay that up against that lip there's not a lot of surface area there but i can tell where i'm making contact because it eats away the ink don't want to take off too much but i want to get the that outside edge clean you never touch the outside you always work on the inside so now that feels sharp to the touch so that's all i have to do now this one i'll darken it as well i don't i don't do the bottom side i'm going to do that top lip so i put that in the vise again come in here you know i need to bend that down a little bit fine try to find where that's making contact maintain that that angle so that you're not having to establish a new one each time and just come in and work that until this edge feels nice and sharp and like i said this is good so it doesn't need if i had to i would come in and have to do a little bit of work on this one a little bit on that one and a little bit on that one be careful where the rest of your file is touching so you're not screwing something else up so that's how you maintain and sharpen or keep sharp your bits now the hollow chisel i've gone through before and i've i've gone in and i have taken a uh you can buy you can buy little grinding wheels that they're gonna call it a wheel that fit in a drill press they fit in a grind a drill handheld drill or they can even fit in a dremel tool and you can find you can buy them to fit that shape so when you put that in it actually makes contact you see this one is too big this one is too small but i found i never really needed to touch that it's going to get scored from the drill bit anyway and unless you've actually damaged it and created a really bad burr there's no reason to wouldn't touch that and you don't necessarily have to have one of these if you did have a burr in there you could go in even if you had to just take a piece of wooden dowel and wrap some sandpaper around it so you could go in and follow that radius just to clean up that lip but what i would do is just spend a little bit of time a diamond i use a trend diamond plate it's it's almost indestructible actually i need to have it sitting below alright i've got to be able to keep this part below and i would go in there and i would just do a little bit of work on this each side of that chisel and what that's going to do is create a nice sharp edge right up here so that when that's being pressed it's giving you a relatively clean surface and it's doing a good job of pulling all those fibers into the middle the drill pulls it up and out of the way and you're good to go now so buy a house as a mortiser absolutely do you have to spend a lot of money on them not really and if you want one just for hobby use this is this has done me well in a commercial use so certainly would satisfy anybody using it for hobby basis hope this helps if you like my work if you like my style of teaching click on any one of these videos to help take your woodworking to the next level and i've always said better tools make it a whole lot easier if you click on the icon with the plane and the chisel it'll take you to our website introduce you all of our tools and also talk to you about our online and in-person workshops good luck in your woodwork

Channel: RobCosman.com

Views: 25,596

Rating: 4.9762106 out of 5

Keywords: hollow chisel mortiser, hollow chisel, mortise and tenon joint, buy a hollow chisel mortiser, Sharpen a hollow chisel mortiser, use a hollow chisel mortiser, chisel, hollow, mortiser, mortise & tenon, mortise and tenon, rob cosman

Id: cIwEzem7NB0

Length: 27min 35sec (1655 seconds)

Published: Mon Jun 14 2021