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Having trouble chopping bench mortises

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  • #21369
    John Purser
    Participant

    First, thanks everyone. I think I’ve confirmed my original hypothesis (the wood is very soft) and with your help I have a couple of ways to go forward.

    The crew installing our sump pumps left early so I went out to the garage, took some pictures, and did some experiments. Pictures attached.

    I found that my plain old ordinary left thumb nail could actually slice into this wood with the grain and easily crease it across the grain. That’s soft! Also the spaces between the dark lines of the rings is over 3/8″ in some places on this wood. When I put my “harder wood” (from a scrap bin, probably Doug fir) 4X4 onto the workmate and started chopping I got EXACTLY the same results Paul shows in his bench making video. At the far end I could set my chisel right on the knife wall, bevel forward, and the knife wall remained pristine after the chisel was driven into the wood. Finally, I pulled out a measuring tape and looked to see exactly what 1/8″ looks like and thought about the slices I was taking on that wood. Some of them were probably closer to 3/16″ and I aint tellin’ if they were over or under that line.

    So, at a minimum I need to take much smaller slices and keep the bevel a long way from the knife walls. Greg I’ve got confidence my chisels are sharp enough but that tip about the sound paid off. It’s different because I’m working on a workmate but the you can hear when the sound goes from the wood to the metal of the workmate. I missed that before. I’ll think about the mortise chisels. I have noticed the bevel chisels twisting occasionally.

    Again, thanks for the help. It’s still a long road ahead but now I can keep moving!

    John

    John Purser
    Hubert, NC

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    #21374
    Jay
    Participant

    Hi John, I have been going through a similar experience learning to cut mortises as I build my workbench. At first, when I watched Paul’s video I thought it looked very easy and fast, but what I found when I started is that it was taking me forever to do one mortise and it was far from clean and pretty.

    I had been using some smaller chisels, which were quality steel, but almost what people would call butt chisels, I suppose. Small handles and short blades. I picked up a set of Narex bench chisels, large full size bench chisels and this really helped me a lot. I could tell they were digging in and levering much better and it made a world of difference.

    The main thing I found is that it just got easier with practice. I would be embarrassed to say how long it was taking me to chop one mortise in the beginning, but the last one I did for my bench I finished in the time it took my girlfriend to run out and pick up some milk at the grocery. So it really is improving for me with practice.

    I offer this up to you, one beginner to another, in hope that it will be encouraging. I think if you just keep at it it will start to get easier.

    #21375
    John Purser
    Participant

    Thanks Jay. I didn’t expect to knock them out like Paul and I knew I’d be practicing before anything useful was produced. But after I had practiced I got results that were very nearly worse than when I started! I just hoped there was a variable I hadn’t accounted for variable because otherwise my “learning curve” was headed in the wrong direction!

    I almost got started with a set of Butt chisels I happened to have when I first decided to build a bench. What stopped me was they wouldn’t fit into the sharpening jig which I needed back then! Then a cheap set of Marples bench chisels popped up on Craigslist and I dodged that bullet.

    And I have noticed that “taking time” is another skill I need to practice mindfully. If I’m not careful I wind up cranking away like I was on a deadline.

    Thanks again for the support.

    John

    John Purser
    Hubert, NC

    #21378
    Jay
    Participant

    John, if you are working with the same home improvement store wood that I am, I have also noticed that it is hard to get clean chops in some of it. It tends to come off in little chunks sometimes, I guess.

    #21379
    John Purser
    Participant

    Jay I’ve been very disappointed with Home Depot but haven’t been able to find a better alternative. Last time I went there I culled 80 studs by actual count to get the 5 I wanted. I also think that here in the North West our “white wood” or spf (Spruce, Pine, fir) comes from trees that are either very soft or full of knots.

    I grew up in the South and framed houses for a while. Down there we got White Pine and Yellow Pine as our standard construction wood. Both are impossible to find up here and as I recall both are far superior to what I’m seeing locally. I think that “generic” studs are regionally distinct, even in national chains like Home Depot. And that’s just in the USA.

    I don’t know about you but I’d kill to have access to the wood Paul used in the bench videos.

    John

    John

    John Purser
    Hubert, NC

    #21380
    Jay
    Participant

    I think it must be regional. I got my first batch of wood for my bench from 84 lumber (not sure if you have those where you are at). It was labeled yellow pine, but most of it being so bad that I replaced it with spf from home depot… most of which was decent, but as you said, took a while to find.

    Finding hardwood in this area is nearly impossible as well… although I have a woodcraft store about an hour away, but it is a bit pricey.

    #21382
    John Purser
    Participant

    Do you live in Colorado? I think we had 84 Lumber stores there.

    I like your profile picture. I’ve decided I like the Stanley planes with the keyhole shape in the lever cap better than the kidney design. Those Sweetheart models and the ones just before them are really nice.

    John

    John Purser
    Hubert, NC

    #21383
    Jay
    Participant

    John, I live just south of Morgantown WV, home of WVU.

    #21396
    Mark Armstrong
    Participant

    John a good way to test how sharp your chisel is to pair some end grain.To get nice shavings.
    If you can do that chisel is pretty sharp. If you cannot get shaving from end grain sharpen chisel.
    You said it your self take smaller bites.
    On your workmate try to make top thicker and clamp your work down to top just make sure clamps not in the way of mortise.
    The more you do to reduce vibration the better for you.

    Dagenham, Essex, England

    #21397
    John Purser
    Participant

    Mark,

    I hadn’t thought of it as a test but I was using my chisels on the end grain of those same legs after I flattened off the tops. They weren’t perfectly square so I lowered the high side with my 1″ (not the 1/2″ I was mortising with) general purpose chisel which is the one that gets used the most. I wasn’t trying for shavings but the chisel would move smoothly through the end grain producing some small curls at first. I didn’t want to take off too much to I used the rest of the leg end to register the chisel against so I could take off dust from the high side until I was satisfied.

    Once a chisel, knife, or plane iron has been stropped I step under the shop light and shave some arm hair. If it doesn’t shave smoothly back to the stones it goes.

    John Purser
    Hubert, NC

    #21878
    John Purser
    Participant

    I’m adding this just for completeness and in case someone turns it up in a search of the archives.

    I finally got back out there and tried to apply all that appears above. Results first, details below for those in a hurry. I did get to the point where I can chop (barely) acceptable mortices in this wood but I’m starting to think it’s not worth it just to use this white wood. Here are the points that I think made the difference between acceptable and unacceptable:

    1) Use VERY sharp chisels AND check the bevel.
    2) ONLY take 1/16″ bites at a time.
    3) Work only while you can focus on the job.
    4) When you start to rush, stop.
    5) Use a lighter hammer for better control.

    As long as I stick to those rules I do fairly well. Not nearly as well as I did on that scrap piece of much harder 4X4 though.

    I found my chisels, Marples brand (and I thought from before Irwin but I could be wrong), lose their razor sharp edge in a hurry even in this soft wood. Chopping even one direction of one side would remove the shaving edge. I’m sharpening 2 to 4 times per hole to keep a razor sharp edge and that’s using Paul’s method including the cambered bevel.

    Also looking at my chisels I found that over time I’d gone from a 30 degree bevel to a 35+ degree bevel. I brought that back down to 30. I’m not certain that was part of the solution but it was a lesson in not taking things for granted.

    I also took a ruler and made a tick mark every 1/16th of an inch all the way up the bevel to help me regulate my bites. Now I’m not guessing. I know how much I’m taking with each chisel bite, at least on the first path.

    I found that with a repetitive task like this I have a certain amount of time where I can truly focus, and every bite is like a separate project in itself. I’m 100% “there” and on task. But after some time my mind starts to wander and my hands keep going. Ordinarily I’d have told myself to pay attention and gone back to work. This time I just stopped chopping and did something else for a few minutes. Again, I’m not 100% sure this contributed to the solution but I think it did and the dog certainly appreciated all the ball throwing sessions.

    I can only stand up bent over chopping so long. Once the back starts gnawing I need to sit down. When I feel this approaching I start working faster to “get it done” or at least get one phase done thinking it would be a better stopping point. Instead of telling myself to slow down I just stopped. Again, out came the ball or sand papers, something I could do resting the back.

    And finally I did switch to a lighter hammer. I like the feel of the heavier one but felt that the lighter one kept my mistake smaller. It takes more passes to get through the wood though.

    The results, as I said, are acceptable but marginally so. I’m sure they’ll hold the bench up, but they’re going to bug me every day they’re down there. The bad news is this makes for a VERY slow process. The good news is I think it’s good training for developing my focus both on the work and on myself.

    John Purser
    Hubert, NC

    #21946
    J_SAMa
    Participant

    A few things to all the beginners building the Workbench (from a beginner building the Workbench)
    I’d try building a smaller bench with thinner legs first… Paul Sellers’ bench is great in design but chopping 3 1/2″ deep through mortises can be too challenging for beginners. Build a shorter bench. Since it’s shorter, even thinner legs will support it. I’ve built a 5′ bench with 2 5/8 legs and it works well (it’s also much narrower than the original design, at 24″).
    Also, practice some 2 ” deep by 3/8″ wide joints first. I find this size most manageable, not so small that it requires super precision, not so big it requires a lot of brute force and hammering. I’d only tried two of those before doing the real joints on my bench. Didn’t mess up a single one of then.
    It’s good if the ends are hollow. Undercut ends actually help reduce friction when assembling and I did this on every joint.
    And again strop your chisel often.
    And

    #21950
    Mark Armstrong
    Participant

    John I have used timber like this in the past.
    It can be pretty hard to tame.
    To me it feels as if it is to dry and instead of slicing through it takes chunks out. Where end grain pretty open seems to separate easily.
    Although you do not want wet timber.
    Do not beat yourself up too much just try and get your entry and exit of mortise right. If you can do more all the better.
    Its one of the reasons I like going to a dedicated timber yard.
    It may be dearer but timber usually better and you do not have to go through whole stake to find a straight piece of timber like you do in the DIY stores.
    Keep at it John it is a work bench and you will beat it up. Just think of the fine things you will make on it.

    Dagenham, Essex, England

    #21958
    John Purser
    Participant

    Sam, there may be some advantage to building a smaller bench first. It would be nice to build one for the grandkids. But at this point I realize part of my problem is not having a bench to work from in the first place! I have got “Practice Mortises” on the schedule before I butcher another perfectly good leg. I think I will start off on some 1.5″ stock and work up. I’m also switching to my other set of Marples chisels to see if they hold an edge better. Mostly I’m just going to keep practicing and paying attention, learning from my mistakes, until I get this down.

    Thanks for the help.

    John

    John Purser
    Hubert, NC

    #21960
    John Purser
    Participant

    Mark,

    I tried to go to the “local guys” for lumber but found they charged more, offered no choice in stock (you take what they bring), and honestly their stock had it’s own problems. Acceptable as studs but not for this work. At least with HD I can pick my stock and choose the problems that are acceptable for me.

    Yeah, this stock could be described as “dry”. On the first pass on a mortise, even when I’m making sure I’m only taking 1/16″ inch per bite with a razor sharp chisel the wood on the bevel side shows small cavities like just running into a 30 degree bevel caused it to tear a little.

    I’m going to keep going. I’ve got a few more things to try to see if I can become more consistent. Practice of course first but also I’m going to look at my equipment and, if all else fails, there’s a local lumber yard that specializes in cedar. I can get clear 4X4s from them for legs.

    I have moments you could describe as “beating myself up” over this but they pass. For the most part I’m just anxious that I learn from my mistakes. I started this thread because I was coming to the conclusion that it WASN’T purely my fault and that made me think I needed a reality check.

    Thanks for the help,

    John

    John Purser
    Hubert, NC

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