I think this tool obviously should exist and I should be finding it, but no. I want something I could mount in a hand drill, and slide through it a big Scotchbrite or steel wool pad or a stack of sandpaper and foam rubber sheeting. This would let me smooth and polish, for example, the 1.125" holes on a tractor implement I’m adapting.
I’m finding drum sanders and wire brushes and abrasive stones and whatnot, but they’re relatively dedicated to one hole size and one abrasive. For example, I can buy an abrasive hone for this hole size, and there are three grits available, but they’re $23 each, so $72 to step through the grits, and it would only do this one hole diameter.
I do find “slotted mandrels” or “split mandrels” with greater flexibility, but only in very small sizes, like 3/32" shaft for a Dremel tool. And I did find one 1/4" one, but the slot looks to be less than 1/16" so it would only hold a sheet of sandpaper, nothing thick.
It seems obvious to have something that looks like part of a blender, or like a paint mixing tool for a hand drill, that I can thread whatever grit and abrasive and padding I need, to do any hole over a wide range.
Try searching for a “ball hone.” McMaster Carr has them (what don’t they have?). They look like a bunch of abrasive spherical grapes on a stalk that you put on a drill and can polish the ID of a cylindrical hole. They also come in a range of sizes, some of them will accommodate a range (1 to 3 inches, for example).
I’ve used them to polish the inside of a mold for candles. Worked great.
Couldn’t remember what those were called. That’s going to be the most flexible device hole size-wise.
. @Napier, depending on what you’re doing, just rotating a smaller sanding drum around the interior of a hole will work. If you think a slotted mandrel would work you could make one from a wooden dowel or other material. Cheap and easy enough to make multiples in different grits.
Can you chuck up a piece of square stock? That would be easy to make into a split mandrel, cut the slot and use some wood screws crosswise to hold the paper. How big are these holes?
I ordered one (a regular one, not what Dr.Strangelove posted). It may work fine, but I’m not sure.
Yes, the hones I mentioned for $23 were McMaster Carr ball hones. I didn’t buy them because it seemed a tad too dear, but wonder if I should have. I may yet.
I don’t have a lathe. I wish I did, for I’d have bored cross holes through the square, and put parallel bars on it with standoffs, and turned the end round.
I also might buy hex stock and do the same thing, but I wouldn’t need to turn the end round, it would go right into the drill chuck.
Hey… I like that! Somehow I missed that! Though, it would have been nice if the sandpaper were replaceable. The cost is higher than the ball hone for a single grit, but if I were buying several grits the cost for this would become lower (I’d only need one shank adapter – they’re all the same PN).
Note, this solution covers a wider range of hole sizes. The flap wheel I would buy would be for 1" to 1.5" holes, whereas the ball hone would be specific for 1.125" and there are different ones for 1.0" and 1.25", so roughly four times less versatile.
I wasn’t aware of the type myself until I looked through the flap wheel selection at McMaster. When I read your OP, I was going to suggest a regular one but knew that they don’t have a whole lot of diameter range due to the density of the flaps. I looked around for ones with sparser flaps but didn’t find one until I just browsed McMaster manually.
Seems like you could make one if you are reasonably handy. Needs a drum shape and some means of pinning the sandpaper strips to it. A job for a 3D printer, I think…
I believe the tool you’re looking for is a reamer. Drill the hole a hair undersize and finish with a reamer. Check the McMaster-Carr and MSC online catalogs for reamers.
A reamer is what I thought of when reading the post title, but I don’t think is a great fit for what the OP actually wants. They’re good at producing a hole with a very specific size; often to a couple ten-thousandths of an inch. I think the OP is more concerned with just getting a good surface finish to the inside of the hole.
Yeah, I getcha - it’s just that using a flap wheel or similar to polish the I.D. of a hole is kind of an offensive idea; you’re practically guaranteeing rounded-over edges and varying inside diameters. Not to mention finding a flap wheel under 1 1/8" when furled. Too bad we have no info on material to be drilled, thickness, final application. Farm machinery? Why bother with a polished finish? Is OP extruding something?
Retired cabinetmaker, here. I used to make wood bookbinding tools, so worked hard maple to 0.002", coached by BIL, a tool and die maker. I owned some small flap wheels, but they were more of a freehand shaping/carving tool.
When I was an assembler in a truck plant we made what you are looking for using large slotted spring pins and abrasive materiel that came on rolls and was about an inch or two wide. You slide the end of the abrasive cloth into the slot in the pin and then wrap enough turns to get to the desired diameter and put the other end in the drill.
Heres a picture of the pins I’m talking about. https://www.huyett.com/blog/introduction-spring-pins
We had ready access to a variety of pin sizes. Sometimes we’d hammer a smaller pin into a larger one to make it longer.
Good questions all. I might have been more specific.
In the present application, I have a welded steel tractor pallet fork that mounts on a standard skid steer loader, and it has three sockets built in for bale spears. The sockets seem to be steel tube with 1.125" ID and about 0.375" wall thickness, welded to the rest of the assembly (it’s all one big weldment). I bought 1.125" OD extruded aluminum bars to adapt this thing to a different purpose.
Trouble is, they’re hard to get in and out. One wouldn’t go through at all until I used a half-round file to work on one end of the steel tube where some welding had intruded into the bore. The machining is rough (which is generally fine for ag equipment), there’s what feels like welding spatter, the paint job is a little gloppy. Seems like if I could just smooth the bore a bit, knock down the high spots, it should be fine. And if the edges got a bit rounded over in the process, that would be a good thing in this case.
The aluminum extrusions are a little rough, too, dinged here and there. Of course it’s not supposed to be a precision surface. I’m going to spin the extrusions against a belt sander to dress those issues up a bit, too.
This is just the latest example of many times I’ve had holes not quite fit, though the misfit is fine enough I can’t see it. I’m often trying to “move” holes a little so all the bolts will fit at the same time, or whatever.
A reamer would be OK if I could clamp this piece on the bed of a big mill. A lathe could have made the aluminum accommodate the steel. But I don’t have any of that and I’m not very skilled. For some reason I can’t drill straight to save my life unless I use a jig or drill press (got those), and usually mess up tapping by starting crooked. If it weren’t for handheld tapered reamers, and drill bits in a hand drill that I wave around a bit, many of my projects would never have fit together.
I can picture this tool that I think would have been helpful many times, and am just surprised I can’t find it anywhere. Later today we will see how the things I do have perform…
A cylinder hone for piston engines might be helpful. I assume someone makes one as small as 1.25"ID, they are usually larger. And they are often used simply to smooth the sides of a cylinder without trying to expand the ID.