Which Chisel size?

[RG55]

Greetings

I intend to buy a new chisel + intend to change a J to an MM, so I'll need to enlarge the cavity (I don't have a router).
With this in mind, which chisel size do you chaps think would be more appropriate?

 

[Old Garage-Bander]

Greetings

I intend to buy a new chisel + intend to change a J to an MM, so I'll need to enlarge the cavity (I don't have a router).
With this in mind, which chisel size do you chaps think would be more appropriate?

IDK... That sounds kind of scary. I'd be afraid of not knowing how the wood grain will react when you stab into it.
I assume that because you don't own a router, that your woodworking skills, at least for the job at hand, are somewhere other than master craftsman level? I applaud you wanting to do this yourself, but would hate to see you bugger-up your bass. Do you know someone with a router who would be willing to help out?

 

[johnh89]

Second the above advice . This is really a job for a router . I think you will regret attempting it with a chisel .

 

[Beej]

Another one on the bandwagon of "that job needs a router".

No offense intended, but if you are also asking which chisel, then I have to presume you are also not familiar with chisels and their use?

If this is a junky bass and you're planning to do this without too much concern over how it looks, then by all means, go for it and have fun. You might even be able to find a MM pickup trim ring (pickup ring) to go around it and hide the sins of the chisel.

The problem with using a chisel is that chisels cut straight lines, and the MM cavity has rounded corners, and also three small bumpouts for the screw tabs. If you carefully drilled out the corners to the correct radius, and also drilled out the locations of the screw tabs, then you could use a chisel to make the straight cuts between those points.

 

[TFM94]

I agree with the above. It is possible to do this with a chisel, but requires very good chisel skills and pre-drilling of corners/tabs. The long sides of the pickup cavity are endgrain and need a particularly sharp chisel. Regarding size, for the straight edges I'd choose the widest chisel that you can fit on that particular edge.

I'd get a router instead, even a hobby-level model will do a good job here.

 

[RG55]

Thanks to all who have replied.
(A "new chisel" implies that I have chisels but are old, @Beej )

Yes, I know this should be a job for a router.

No particular problem with the rounded corners, because the length of the J pickup is actually bigger than the MM's.

I do intend to use drills for the screw tabs.

I agree with the above. It is possible to do this with a chisel, but requires very good chisel skills and pre-drilling of corners/tabs. The long sides of the pickup cavity are endgrain and need a particularly sharp chisel. Regarding size, for the straight edges I'd choose the widest chisel that you can fit on that particular edge.

I'd get a router instead, even a hobby-level model will do a good job here.

The widest chisel that fits seems like a good suggestion, thanks.

 

[GMC]

My advice is find a friend with the experience and tools to help you. Choosing the wrong tool is one way to really make a mess of your bass and poor Chisel craft can seriously damage your health. One slip and you can easily end up in hospital with stiches or worse.
Some things are in the remit of a luthier because that's what they do best. If you don't have similar wood craft skills and don't have the tools then please pay someone to do it for you.

 

[Jeff Siddall]

(A "new chisel" implies that I have chisels but are old, @Beej )

Yes, I know this should be a job for a router.

You could get a sharpening setup for your existing chisels, but if you go with stones (instead of, for example, PSA) you will spend more than a router.

A Bosch Colt will cost about $120 US, maybe less if you can find a deal, and will do a great job of pickup cavities.

Good luck!

 

[T_Bone_TL]

Thanks to all who have replied.
(A "new chisel" implies that I have chisels but are old, @Beej )
...
The widest chisel that fits seems like a good suggestion, thanks.

You might as well sharpen the old chisels, since the new chisel probably won't arrive properly sharp and will get dull even if it does. A low-rent hand router-plane is easy to make, for that matter (drywall screw or Allen key as a bit, either one ground sharp without overheating to lose the temper. Held in a stock of scrap wood.) "Scary-sharp" will find some tutorials and likely some spammy crap barging in on the search results, so keep shields up until you verify actual old-tools content.

If hacking at it with only a chisel, I'd actually pick a fairly narrow one (1/4" or so) as it's easier to control and hand-power for finesse than a wide one. Also gives you more angles than the widest one that fits and can't be twisted. Use bevel-down, take shallow cuts (control...), watch the grain direction.

 

[Bruce Johnson]

I agree with the general advice above that this job is better done with a router, but.....

If you are going use chisels, I recommend a 3/8" chisel and a 3/4" chisel. It doesn't really matter if they are old and beat up or brand new, as long as they are sharpened correctly. I've got shelves and drawers full of chisels in all sizes and conditions, and those are the two sizes I use most often by far. Third place is 1/8".

Basically, use the 3/8" chisel for most of the wood removal. Smaller bites, less pushing force, better control. The bigger chisel is for smoothing out surfaces and edges. I have chisels wider than 3/4", but I don't use them often. I find them harder to control. Too much force required, and harder to steer straight. Good chiseling is all about working smoothly and easily and steering accurately.

 

[1n3]

I like chisel work, and am pretty good at it. Still, I agree that this is best done with a router. I probably couldn't equal the appearance of a good router job with chisels, but the top edges are most important, appearance-wise... the walls and bottom matter less. If you proceed, I'd suggest taping first, and scoring completely through the finish with something like an xacto knife before the chisels come out. That should help keep those top edges straight, and minimize finish chipping.

As for chisel width, I'd probably do most of the removal with a narrow chisel, for more control. And my answer to "what size?" could be "your sharpest".

 

[bassliner50]

I would not use a chisel. Maybe check Craigslist etc. buy a used router with a 3/8" or 1/4" collet (chuck.) Probably would come with a few bits too. Practice on scap wood until you have the skill and confidence. Use a felt tip to mark the cut. Don't go full depth all at once, move counter clockwise. take it slow, while working keep cavity clean so you can see the cut. Then build a kitchen countertop for your wife.
If you still insist on a chisel, I would use one with a small flat point. Maybe 1/4"" across. Use a sharpening stone for the edge. ...Much better to use a router.

 

[micguy]

A router will cost less than the body you're going to buy after you butcher your present one. Even with a router, getting things lined up is a bit tough, but it looks 100x better, unless you've got 50 years of woodworking experience.

 

[shnapper]

By the time you buy all the proper tools and butcher your current bass you could just do like I did yesterday and buy this cheaper…

 

[Crawforde]

Careful work with a sharp chisel is enjoyable and effective, but you can’t rush it,
The key is small bites, controlled cuts, pre drilled corners and cut lines some patience and enjoying the process. if you just want a hole, then chisels are a recipe for destruction. If you want to chisel the hole, and enjoy the work then go for it.

 

[2groggy]

Getting a router is one thing. Then you need the matching bit with collar or bearing, template and clamping system.

I've cut several one-off cavities with chisels when I didn't have a template. Make sure that your tools are sharp. Work slowly and carefully. It's really no big deal.

1. Layout your line work
2. Double check your line work
3. Drill the corner and lug holes
4. Scribe the perimeter straight lines with a straight edge and sharp knife
5. Hog out as much material as you can as near to the scribe lines as you can
6. Chisel the sides by aligning the blade tip in the scribe line

 

[Crawforde]

Speaking of chisels.
An old Swan 3/8” socket chisel arrived today. it came from a luthier I purchased a very nice Swan Gouge from a while ago and was a deal I couldn’t turn down.
I made a handle from some scrap oak. Once I tweak the shape to a good comfort level, maybe I’ll make a new one from some pretty wood. The blade is under the handle
After this pic was taken I faceted the rear portion like a London pattern chisel handle

 

[Durham52]

My first solid bodied electric guitars and basses had all control cavities and pickup pockets made with drills and chisels, but I was trained by a cabinet maker in using hand tools. Even so it was slow going compared toa router. (dovetail joints, mortice and tenon joints and all that) If you can sharpen a chisel correctly (so that it will cut wood cleanly, with minimum force) and know when to use it which way round, then go for it and work slowly. A very sharp chisel can be a dangerous thing in the wrong hands and and a poorly sharpened or slightly blunt one can be even more dangerous, because if it slips, there will likely be much more force behind it...

These days routers for light work can be picked up fairly cheaply and are quite serviceable for occasional use. I have a copy of a Makita trim router mounted in a sled, for fretboard radius' and it's served me well for a few years. I use higher powered Makita routers for heavier and more frequent work, but most guitar/bass related tasks can be done with lighter powered units, especially if you're not using them all the time. A cheap basic, but serviceable router will likely cost no more than a good chisel and to begin with just buy the bit, or bits, you need, you can always add others later. Learn how to use a router and you'll be surprised at all the jobs you'll be able to use it for.

 

[Bisheri]

I'd use a 3/4" chisel plus an 1/8" chisel with a rounded off back(in combination with a drill) for the round parts where screws go in. 3/4" is ideal because larger size are harder to control. Just be patient and go slowly.

It's doable.

 

[GMC]

In reply to my earlier comment, here's a list of chisels that I used for the following bridge cavity. Making a template and then using a Router would have been quicker and neater. However, more effort and tooling for template. Getting clean corners and lugs is the issue. If you are swapping the rear pickup then you don't have the safety of covering it with a pick guard.
I have a set of cheap mini carving chisels that have two curved carvers. These help a lot. Then I used a range of flat chisels, seen below. These were cheaply sources, but needed a lot of honing and sharpening to make them fit for service. So add a Japanese combo water stone to your kit too. A 2000/8000 should do the trick. You will also need to spend time laboriously flattening the reverse side of each chisel. A bit like lapping / honing a new plane.