Saturday, September 5, 2015

Making a new kob for hand planes - Part 1

Most, if not all, of the vintage hand planes I pick up have front knobs that are in decent shape but from time to time, and for various reasons, there's a need to make a new one. The most common reason, as you can guess, is that it's either missing or broken and can't be repaired. Another reason, and the more usual one, is that the rear tote is either missing or broken beyond repair. I don't know about you but I am picky enough that I want the knob and tote to match on my planes, both the ones I use as well as the ones I sell. If you buy from me you'll get this as an option.

I am definitely not the first person to write on this subject and the article at was my starting point for turning my first knobs. The method there produces a bit of waste at the bottom of the knob and I was unable to get my drill press to center correctly on the ones I turned. That method also requires you to sand off the lathe mounting marks on the top rather than round over the top on the lathe. I modified the method into my own, that's what I'm going to describe here.

After reading how pens are made, I set off to develop a method to use a mandrel to turn the knobs. Nothing against the other method, I know the author successfully makes tons of knobs that way but I wanted to present an alternative method that required a little less finishing on the top of the knob. That and I wanted to present a method using a mandrel as an option. Those of you that make pens should have one around already.

My method will require a mandrel that allows the shaft to go all the way through the mandrel base, I purchased this one from Woodcraft and thus far it has served me well. I would imagine it cane be done with a mandrel where the shaft can't go through but I have not tested it.

One disclaimer before I start: I am very new to wood turning, in fact at this point I think I have been turning for maybe 3 months. One of the first "real" things I produced on my lathe were plane knobs and I might go so far as to say I purchased the lathe to make them. So bear with me where I might use incorrect lathe/tool terminology and might do something inefficiently. And by all means post comments with corrections, suggestions or ideas on how to improve the process.

Make a template

Before you start turning you're going to need a template to work from. The example used in here is a taller knob for a Stanley Bedrock 605 plane but the process remains the same regardless of plane. You will, of course, first need a knob to start with so beg, borrow or buy one to use as your source. In my case a regular Stanley Bailey no 5 tall knob is the same as a Bedrock 605 so I started with that.

I purchased a 5" copy gauge at Woodcraft to steal the profile from the existing knob for a whopping $10.99. Either visit one of their stores or purchase one online here. I would imagine there are other versions, perhaps even metal ones, of these out there but this one was sufficient for me.

I started to create the template profile by pushing the knob into the copy gauge half way in, to the center of the hole.

I used a scrap piece of 1/4" hardboard I had around and on the side of the copy gauge opposite the template knob trace the profile on the hardboard. Why the opposite side? Well, you need the mirror image of the knob to check against as you turn the new one. Cut the template on the band saw, or using a fret saw if you're the unplugged type then sand it smooth to the line. Every once in a while place the source knob in it as you're sanding to make sure you're getting the profile correct.

In hindsight I should have used a larger piece of hardboard but I'll make another later. I also cut a bit too far on the bottom so I had to mark where the bottom of the knob should start.

Remember to mark/label this template so you know what it's for later. As you make more you will amass a pile of templates and to be honest, they all look about the same.

Create a turning blank

Next up will be creating the blank you'll turn your knob from, in my case I needed a 2"x2" square that is 2 5/8" long. Your mileage may vary on your plane but the previous dimensions are for a Stanley tall knob for a no 4 and 5. Maybe one day I'll put up a page that lists the necessary blank sizes for each Stanley knob (yea, right). Or, if you'd like to help the cause, feel free to come up with all of those dimensions and send them to me to post here.

Pick whatever wood you like, the originals were a type of Rosewood called cocobolo which, while it can be obtained today, is thoroughly expensive. I heard that at one point Stanley had their own plantation in South America where they grew and harvested their own cocobolo from. When I'm in an extravagant mood I'll use that. Otherwise, any good rosewood will suffice and will be an almost identical replacement, I also have come to like walnut and even beech. They're both relatively low cost, turn nicely, finish well and have a great feel (and look) to them. The most important part of the selection is that it needs to be a hardwood, don't use pine or fir.

As mentioned before, I like the knob and tote to match and if you're in the same boat, remember to keep that in mind for cost. You'll need enough to make both the knob and the tote. Walnut is extremely cost effective for this as are some of the more common rosewood species, yuccatan comes to mind.

I started with 12/4 walnut from the lumbar yard and milled the material to 2" thick with my Dewalt thickness planer. Why 12/4 you ask? That provided just enough extra to mill both sides without wasting a ton of material. After that I ripped that into 2" wide pieces, each one was around 16" long from the piece I bought at the yard. After checking for square I set the miter gauge on my table saw to 2 5/8" and proceeded to cut out 4 blanks. Check for square again, at this point it really does matter before you proceed to the next step.

Using whatever tool you prefer, mark the center of each side of the top and bottom of the blank. I use my combo square as you can see in the image. I use a sharpie to mark with, especially on darker wood; pencil lines just aren't easily seen. Once marked punch a hole in the center using your favorite awl, this will be the starting point for the next step where you drill the holes. Punch the hole centered, it makes a difference later when you drill. At this point you have a basic blank, I take several of them to this point so they're ready to go whenever I need.

Drilling Holes

I experimented drilling the holes in all sorts of orders, before, after, in several stages and discovered that the simplest and most accurate method is drilling all of them first. This is also precisely why I went down the mandrel path to start with, drill everything centered first (like with pens) then attach it to the mandrel and turn.

With the other method you need to flip the knob over to the top side to drill the bottom hole which, in my case, was never centered. I know many of you out there won't care if it's not completely centered, I do. I'm sure it's not perfectly on center all the way through but it's dang close. And again, that method works great for some, not so much for me and in all things woodworking there are at least 236 ways of doing things.

Drill the top hole first using a forstner bit, this is the hole where the brass screw cap will go. I measured the depth of my sample knob and marked a dowel rod with it. As far as I know many Stanley brass caps are 7/16" which is what I used, check yours first. Drill a bit then check the depth against the dowel rod. Drill a bit more and check again. You get the point. The depth here needs to be fairly accurate since the top of the brass cap is of a certain length. You can adjust a bit later if you go too deep but if you're going to err on the side of caution on the top, go a little shallow, you can deepen it later if necessary.

I used a caliper to check both the base of the 605 Bedrock this knob would go on as well as the sample knob I was using, in both cases I came up with 5/8". Using the same method as above, use a forstner bit to drill out the bottom of the blank. I used the same method with the dowel rod to check the depth but it doesn't matter as much on the bottom, you won't see it. At this point you can test it on the plane to make sure it clears deep enough.

The last step is to turn the blank back over so the 5/8" hole is on the bottom of your drill press table. Load up a 9/32" drill bit and starting on the point left by the 7/16" forstner bit drill all the way through. This is where it's critical that you squared your drill press table against the chuck on all sides and it is critical that the blank you made was square on all sides. If either of those things weren't done correctly this hole will not go through the center. If for some reason it doesn't, flip over the blank and starting on the point left by the 5/8" forstner bit drill halfway through that way. I can guarantee you if you have done your due diligence to this point it will drill through point to point.

If you have a bolt and brass cap around you should be able to test out the fit through the hole at this point. This is also the point at which you could drill the 7/16" hole a bit deeper if necessary if the brass cap extends above the top a bit. The brass cap should fit snugly inside that hole but if not then
I'm guessing you have one either earlier or later than I do which I would love to hear about. This information would be great on that table of blank sizes mentioned earlier, whether or not the various types have the same diameter brass caps.

Mandrel Setup

Now that you have a blank all ready to go it's time to setup for turning. This is the point in which the mandrel method starts to show its advantages. However, it does have one downside here: you'll need bushings to secure it to the blank. With samples and caliper in hand I visited my local Woodcraft and tested every pen turning bushing set I could get my hands on. Not a single one was either 7/16" or 5/8" and I checked probably 50 bushing sets. Luckily I have this lathe thing at home in which I can make my own!

I tried the plastic "universal" bushings that essentially fit themselves into any size hole. I initially started making knobs using those and found several downsides. They take quite a bit of time to fit themselves, you'll spend hours compressing them into the holes until they hold the blank securely. They also need to be considered sacrificial so you'll need to replace them from time to time. I'm guessing you're like me and have lots of scrap material around that you can use to make your own. It honestly takes less time to make your own than it does to get the universal plastic ones to fit and hold correctly.

You'll need to make 2 bushings, a 7/16" one for the top and a 5/8" one for the bottom. I used scrap material I had around, some of them are walnut, others are maple and I think a few are beech. I turned the largest part first then with a parting tool turned the other bit down to the required size, constantly checking with my caliper. I took them to the exact measurements, 7/16" and 5/8", and counted on sanding to take a little off so they wouldn't be obscenely tight in the blank.

When they're all done attach them to the blank you made and slip the whole thing on the mandrel. Slide the mandrel shaft all the way down and tighten the nut on top. In the end here's what you have that will go into the lathe for turning:

At this point you're probably thinking "dang, this is a lot of prep work just so I can turn a knob" and you're pretty much correct: it is. Remember this the next time you think about complaining about the price you're paying for replacement knobs when you buy them.

Remember this though, making templates is a one time thing for each size knob and from what I can tell, the bushings can be used on many Stanley planes. The 7/16" and 5/8" sizes, from my testing, fit on many planes from no 3 to no 8. They're also simple to make if your plane differs, I'll post another article that shows you how to make a dozen of each size at a time. They should be considered sacrificial so make several of them.

Up to this point I have spent $36 on bits and pieces from Woodcraft. If you're willing to wait and search around you can probably find the copy gauge and mandrel at a lower cost than Woodcraft.

Now we're ready to move on to actually turning the knob which I'll post in part 2 of this series.
Why a part 2? I need to go out and take some pictures as I turn one.... More to come.