Crucible Lump Hammer: Specifications

Posted on 22 November 2017

Manufacturing a lump hammer was one of the dozen or so things we wanted to make before we even incorporated Crucible Tool. It’s a tool I’ve been experimenting with in my personal shop for years by modifying vintage hammers to get the balance and feel that I wanted.

Before I discuss the specifications of the lump hammer, however, let me first answer a question several customers have asked: What in the tarnation is a lump hammer?

In the United States, it’s typically called an engineer’s hammer or a small sledge, and it comes in a variety of configurations – different head weights and different handle lengths. In the United Kingdom, the tool is sometimes called a lump hammer and is a tool that shows up in the kit of many 20th century woodworkers, including Alan Peters and David Savage.

The lump hammer is used for everything that a wooden mallet is used for – mortising, assembly, disassembly, chopping dovetails, setting holdfasts, persuading stuck joints. It’s advantage (in my opinion) is it has a lot more punch in a small package. And a lot of woodworking operations can be done without swinging the tool. You merely lift it and drop it – gravity and mass does the work instead of your arms.

During my tests, I worked with a variety of weights, handle sizes and metals to find a lump hammer that was balanced, durable and something I reached for at every opportunity. I am not a fan of cast iron heads, which are common, so we settled on a steel head that is milled directly from a 4140 QT steel (usually called 4140 prehard) that's prehardened to about Rc 28-35. The head is 1,000 grams.

The handle is just as important as the head. Ours is octagonal in section, made from hickory and is 9-1/2” long under the head. During the last year, I think we’ve fussed over the handle more than any other aspect of the tool. The handle has a charred black finish and is coated in soft wax.

The tool will be $85 and made entirely in the United States from domestic materials.

I know that several commenters have noted they can go to Harbor Freight and purchase a similar-looking drilling hammer for $5.99. Is our hammer 14.91 times better than the Harbor Freight hammer? Of course not. It’s 15 times better.

As always, we make these tools for ourselves and our use in the shop – not to a price point. We think the price is incredibly fair for what the hammer is, but if you don’t get that, we don’t seek to change your mind.

The lump hammer is coming soon, just as soon as we can afford the bill for the steel.

— Christopher Schwarz

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  • David Brown: December 06, 2017

    Just for fun, 15 ways a 4.99 hammer is inferior:

    1. Head is painted (probably soft black paint)—in use will mar adjoining surfaces
    2. 2-1/2 lbs—1/2 pound too heavy
    3. lacquered handle—feels plasticky, slippery
    4. 8in handle—too short, limits grip positions
    5. handle is oval shaped—harder to clock in your hand
    6. handle is reverse traditional tapered—fatter near the head, hourglass near the butt
    7. handle is shaped to force your hand to one position
    8. head hardness—unknown
    9. country of origin—unknown
    10. what was the designer thinking when he noodled the tool—unknown
    11. where are your dollars going—unknown
    12. species of wood for the handle—unknown
    13. how is head wedged—unknown
    14. has to be fettled before first use—strip the lacquer, oil or wax the wood
    15. MOST IMPORTANTLY: does looking at it make you want to pick it up just to see how it feels in your hand—no

  • David Brown: December 04, 2017

    Looks nice. I want one. The other similar sized hammers I have are for pounding on things outside or beating cold chisels. Looking around online and researching, there aren’t any options if you want a lump/engineer/club hammer this nice. Most have painted heads, nice for marring your work. Some have fiberglass or plastic handles. No thanks. I love the charred, octagonal handle and the overall aesthetic. $85 is certainly a fair price. I’ll start looking for the “add to cart” button sometime after the holidays. ;-)

  • Don Carlyle: December 04, 2017

    Noob question here: You say you use it for mortising and chopping dovetails. I always understood that you should hit a wood chisel handle only with a wooden mallet. Have I been misled in that regard? Will using the lump hammer cause premature destruction of chisel handles?


  • raney: November 28, 2017

    Chris – I don’t oil my handles, personally because I’ve never needed to. But the charring shouldn’t interfere any in this case – it’s done with high heat, and barely penetrates the surface. Adding oil to the endgrain should work just fine.

    Gavin: the eye is a half-hourglass. Tapered at the top, but not the bottom. We put a pretty hard flare on the handle at the bottom which eliminates the need for it as long as the fit is really solid. The eye tapers about 3 degrees from the midline to the top face, to work with the wedge to keep things locked down.

    I’ll try to put together a working drawing of everything in the next few days, if I can squeeze a little more time out of the day.

  • raney: November 28, 2017

    Bruce and Bob – regarding the angle of the faces: it’s a trick of the lens.

    Short answer is that the faces aren’t angled (just radiused) because these hammers get used so many different ways. Designing for one type of swing would be limiting for a very generalist tool like this.

    While an angled to face is important for dedicated-use hammers where you want maximum force transfer (nail hammer, framing hammer, forging hammers, etc) — we find those angled faces limiting for a much more generic use tool like this. We do keep a fair bit of radius on the faces (in the 8-10" range) to prevent those terrible vibrations when you misalign a face, but we find that to be more than enough adjustment. None of the lump/engineer’s hammers we use, or have looked at, had angled faces – which I think confirms our bias.

    I think of the lump hammer as a really ergonomic version of the brick, or rock, or big hunk of metal you might grab when you need to ‘convince’ a joint to go together, or to separate an over-tight test fit. I used to look for something compact and heavy so much, I eventually started keeping an old sledge head under my bench. Then later I [picked up a short-handled mini-sledge and found it an improvement.

    Eventually I saw Chris’ lump hammer and found out that Alan Peters advocated them extensively – so I decided I didn’t need to hide mine anymore when I had visitors.

    And half a decade later, here we are with our own version. And shiny.

    In all seriousness – a sturdy and fairly smooth fist-sized rock would do most of these jobs quite well. But adding the handle gives you more options – and gets your hand much more out of the way (a very good thing).

    The more refined look of ours, and the type of steel, is mostly about making what we see as ‘the perfect’ version of the hammer. Nobody NEEDS a perfect one – but I’m pretty sure nobody who buys one will ever buy another one. At least that’s the idea.

  • Gavin Rondeau: November 27, 2017

    Is the eye milled into an hourglass or is it a straight sided hole? I’m used to thinking about this from the standpoint of forging operations, which you’re obviously not set up for. Just curious.

  • David Nordrum: November 26, 2017

    When I first saw it, I thought why…the more I look at it and think about it…
    Sooooo want it! Can’t wait!

  • chris johnson: November 25, 2017

    Might be a dumb question but does charring the handle/coating in soft wax prevent oiling it over the years to keep the head tight? If so how can this be overcome?

    Chris Johnson

  • Marcelo Simoes: November 24, 2017

    I am looking forward to purchasing this hammer. I suggest you to also make a shaping axe !

  • Michael: November 23, 2017

    Dead damn sexy. What’s that tingling sensation and how did my credit card get in my hand?!?

  • Mark Baker: November 23, 2017

    1 lump or 2 ?? may be the English wood say !
    Here ,in Hawaii, we have the prefect wood for the Lumper , Kiawe or mesquite . Its history includes it being used for road pavers before asphalts roads . It tough and must be worked with carbide tools but once you craft it to the size you want , it takes and licking and keeps kicking .

  • Bill Ranseen: November 23, 2017

    I’ve seen guys wielding 28 oz. framing hammers, but for me, a 2# plus hammer is much more comfortable with a shorter handle, like the Estwing drilling hammer, which I’ve had for a couple of decades and like very much. Otherwise, I use a two-handed sledge.

  • warren postma: November 23, 2017

    I’m almost 50 and I’m done with even wondering if the harbor freight thing is any good. The geometry on this looks like someone actually thought about it. That alone is worth $85 to me.

    Warren in British Columbia

  • Bruce: November 23, 2017

    That is very obviously a superior hammer, just from looking at the photo.

    I don’t know how many hammers I’ve seen where the faces are at 90 degrees (or worse) to the handle which almost guarantees a miss strike. And then there are the ‘special’ hammers where every one in the bin has the head on upside down – held on by a pool of what I hope is good epoxy but is probably the cheapest polyester resin you can imagine (starts to break down over 70 degrees F !)

    As for materials, I suppose we are going to miss out on the limited edition Ultra High carbon steel version? You could use MilSpec gas turbine blade blanks as feed stock if you were near a large Defence contractor’s plant ;-)

  • Bob: November 23, 2017

    Interesting angle to the face…

  • Jonathan Schneider: November 23, 2017

    I know this tool under the gentle name „Fäustling“ like a cute little fist. Kind of makes sence to me hitting dovetails into another with this or the side of your fist. Hammer looks fantastic btw!!

  • Dave: November 22, 2017

    That’s one sexy basher! Hope you sell a boatload.
    A maker’s mark would be nice but sounds like you’re not forging/heating…

  • colsdave: November 22, 2017

    “There is hardly anything in the world that some man cannot make a little worse and sell a little cheaper, and the people who consider price only are this man’s lawful prey.” John Ruskin (aka Baskin Robbins ‘quality quote’)

  • Caleb James: November 22, 2017

    The 15 times better remark killed me. I laughed so hard. Mostly because I’m sure it’s true.

  • Artisanal Facts: November 22, 2017

    Giving it the English name will certainly help with sales.

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