Here is a stupid question. I want to set up a rotating shaft, to extend out through a front panel on my DIY preamp. I thought about using ball bearings. Here is a picture of what I am talking about:
1. Assuming I have a shaft that will fit inside these, doesn't it need to be tightened to the inner metal ring? I can't see how this would be done, any ideas how you do this?
2. Next I need to mount the outer section of the bearing so that the shaft is perpindicular to the front panel, and can extend through a predrilled hole in the front panel. How would I do this?
3. I've seen "pillow block" ball bearings which look like they are perfect for this task, but most of those have .5" bore or bigger, I'm looking for .25" (6.35 mm) bore, to fit in a tight space with a .25" shaft, these are just too large and bulky. Are there any other options that you can think of? These pillow block things are very nice but are much to large for my application. Ideally I'd like a super small one for a .25" shaft, any ideas?
Here is a pillow block
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1. Assuming I have a shaft that will fit inside these, doesn't it need to be tightened to the inner metal ring? I can't see how this would be done, any ideas how you do this?
2. Next I need to mount the outer section of the bearing so that the shaft is perpindicular to the front panel, and can extend through a predrilled hole in the front panel. How would I do this?
3. I've seen "pillow block" ball bearings which look like they are perfect for this task, but most of those have .5" bore or bigger, I'm looking for .25" (6.35 mm) bore, to fit in a tight space with a .25" shaft, these are just too large and bulky. Are there any other options that you can think of? These pillow block things are very nice but are much to large for my application. Ideally I'd like a super small one for a .25" shaft, any ideas?
Here is a pillow block
The most elegant solution is a linear bearing:
it consist of very small balls within. Beware though, the ones sold on ebay <$15 are of no good quality. These bearings are $$$$$
Ralph
An externally hosted image should be here but it was not working when we last tested it.
it consist of very small balls within. Beware though, the ones sold on ebay <$15 are of no good quality. These bearings are $$$$$
Ralph
Use a cheap nylon flange bearing instead. Drill a hole through the panel to match the outer diameter of the sleeve, maybe even a bit oversized... you don't want a tight fit on the shaft for this type of application. Push the bearing in from the outside such that the flange seats on the front face of the panel. Use some epoxy adhesive if the fit is loose.
This should provide for a smooth action when turning, and the flange provides a low-fricition face for the knob to rub against as well if needed in case you put too much pressure on it when turning.
Nylon flange bearings can be purchased from MSC or McMaster Carr (or, possibly, from stores like HD and Lowes as well) for just a dollar or so in 1/4" size.
This should provide for a smooth action when turning, and the flange provides a low-fricition face for the knob to rub against as well if needed in case you put too much pressure on it when turning.
Nylon flange bearings can be purchased from MSC or McMaster Carr (or, possibly, from stores like HD and Lowes as well) for just a dollar or so in 1/4" size.
BTW, you do not want to use linear ball bearings. Linear bearings are made for just that... a linear motion of the shaft. They are not designed for rotation, and in fact many are designed specifically to resist rotation. Turning a shaft in a linear ball bearing will wear quickly wear the shaft, the bearing, or both, and the "feel" of the turning motion will likely be about as smooth as a stick in a cement hole.
Teflon/Freelon lined linear bearings work very well for both rotational and linear motion, and that is their primary benefit. Much more expensive than standard nylon though, so I don't see any reason for using one in this application.
Teflon/Freelon lined linear bearings work very well for both rotational and linear motion, and that is their primary benefit. Much more expensive than standard nylon though, so I don't see any reason for using one in this application.
lgreen said:
I don't know if bearings are the right way to go on this but if you are looking for small bearings then www.smallparts.com might be worth looking at.
James
You don't need ball bearings as a bushing will suffice. The easiest way to do this is to get a sheet of plastic. UHMW-PE, nylon and Delrin will all work in this regard. Use the same drill bit as the shaft diameter. If metric, then use metric bits. Using a hand drill will create the needed gap to make the rotation smooth. More looseness can be made by taking some fine sandpaper and rolling it into a stick and spinning it in the hole.
You can cut the sheet slightly smaller than your front panel (to fit inside the enclosure) and drill all the holes in the right places. Or you can make square blocks about 1/2" larger than your knob. Then drill 4 holes from the front and using small metal screws for an industrial look.
ensen
You can cut the sheet slightly smaller than your front panel (to fit inside the enclosure) and drill all the holes in the right places. Or you can make square blocks about 1/2" larger than your knob. Then drill 4 holes from the front and using small metal screws for an industrial look.
ensenAttachments
small pillow block bearings are available- I found some at a surplus place for 1/4" shaft. The shaft is a friction fit in the center of the bearing. It is really smooth - especially with a massive knob. It's true that you don't need anything this fancy though. Try McMaster Carr or however it's spelled
The absolutely easiest way to do it is by using those plastic washers from Home Depot. Outside dia. 1/2" , inside dia. 1/4".
If your front panel is thick enough, drill a hole with this 1/2" bit (DeWalt, available from HD as well) to the depth of two stacked washers or slightly more. Enlarge pilot hole with a bit size slightly bigger than 1/4". Glue both washers into opening with crazy glue. I'm using two washers as one is sometimes too loose (too much play on a shaft).
Get a 1/4 brass rod from Home Depot and use it for shaft extender. You may use a plastic pipe (used for water connection and available from HD as well) to connect shaft to the extender.
If your front panel is thick enough, drill a hole with this 1/2" bit (DeWalt, available from HD as well) to the depth of two stacked washers or slightly more. Enlarge pilot hole with a bit size slightly bigger than 1/4". Glue both washers into opening with crazy glue. I'm using two washers as one is sometimes too loose (too much play on a shaft).
Get a 1/4 brass rod from Home Depot and use it for shaft extender. You may use a plastic pipe (used for water connection and available from HD as well) to connect shaft to the extender.
Attachments
For your info, that's a German made, titanium drill set.
I've been using those drill bits for years and find them the best for a job (and readily available). And I don't mind drilling a pilot hole. Actually, to make an accurate 1/2" hole you NEED a piloted drill bit. And I'm not aware where you can find cheaper, good quality, flat tip drill bits, than those "Bullet" set from DeWalt?
You probably didn't use a drill press too often?
135° tip is no good here.
I've been using those drill bits for years and find them the best for a job (and readily available). And I don't mind drilling a pilot hole. Actually, to make an accurate 1/2" hole you NEED a piloted drill bit. And I'm not aware where you can find cheaper, good quality, flat tip drill bits, than those "Bullet" set from DeWalt?
You probably didn't use a drill press too often?
135° tip is no good here.
li_gangyi said:
If possible, don't clamp your piece to the table (unless you drill thin sheet metal). You prevent self centering action of a drill this way. But this is possibly dangerous, as the bit might grab the piece and damage your fingers, happened to me few times. What I do now is to clamp a wooden block, beside my piece, and this block prevents the piece from rotating.
I understand it may be a controversial advice, but it always worked well for me.
I use vice very rarely.
Peter Daniel said:
Still cheap enough to be suspicious. I've broken and dulled several of them doing what should be normal service. And no drill bits are titanium!!!!!! Argh!!!!! It's a titanium Nitride coating to reduce friction!
The classic saying goes:
Time, money, quality. Pick two.
Cheap != quality. You get what you pay for. Etc. For one thing, you probably shouldn't be looking in Home Despot. (Think about it, big box store, reminiscent of Walmart eh? Doesn't exactly ring of quality.)
I use the drill press for everything I can... much easier going and doesn't kill the cordless' battery. An invaluable tool.
As far as 135° tips go, I think the 1/4" drill (which had to replace that set's original 1/4" bit because it was ground so badly it wouldn't even touch a pine board, let alone steel or aluminum plate!) which I use works very nicely. If nothing else it won't pull though all at once, and that would be a rather disturbing thing to have happen at 1,500 RPM drilling a 1/2" hole in say, bronze!
Tim
Sch3mat1c said:
at 1,500 RPM drilling a 1/2" hole in say, bronze!
That just confirms that you have no clue what you are talking about. No wonder your bits get dulled too early.
Think: Time = Quality
Although 1.750 RPM is a recommended speed for soft metals (on a back of my drill press) I never go more than 600RPM when using 1/2" bit. Anything more than that seems simply unreasonable.
And of course I know those DeWalt bits are not made of titanium, but that's a common name for them. But I also have some pure titanium drill bits.
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