| lgreen |
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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| sreten |
As far as I know all you need is a plain plastic bearing.
You just drill and ream a hole in a flat piece of
plastic and attach it to the rear of your panel,
or a panel slightly behind the front panel.
:) sreten. |
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| rwagter |
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 |
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| tiroth |
| I think you may be overengineering. I just drill a hole for the shaft to go through. |
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| RHosch |
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. |
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| jwb |
| Normally a shaft is pressed into a ball bearing. But, as the others said, a ball bearing is all wrong for this task. Just use a nylon sleeve, and if you don't like the fit you can use a permanent lubricant. |
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| RHosch |
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. |
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| jwb |
| Speaking of Teflon, Delrin has a really nice feel in this application. You can buy it in raw form and cut and drill it yourself easily. |
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| nemestra |
| quote: | Originally posted by lgreen
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. |
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 |
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| purplepeople |
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 |
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| Variac |
| 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 |
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| Peter Daniel |
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. |
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| Sch3mat1c |
:rolleyes: That drill set sucks for metal. *Reqires* a 3/16" predrilled hole for it. Get a real 135° tipped drill, real highspeed steel, not the Made In China ****.
Tim |
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| Peter Daniel |
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. |
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| tiroth |
| You drill 1/2" holes with no pilot? :rolleyes: |
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| Peter Daniel |
| Working in an aircraft industry, allows me to have access to all sort of cutting edge tools. Like for instance, that quality, high speed drill bit, marked as 561-11-15 mk27. I still prefer to use DeWalt ****;) |
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| li_gangyi |
| WoW~!! Nice drill...I really use **** drills, but I get to use a bench drill that helps keep my work centred and gives me neat holes...I found that adding oil to the drill if u're drilling acrylic (lexan) gives it a smooth finishing inside..anybody else got any drill tips?? |
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| Peter Daniel |
| quote: | Originally posted by li_gangyi
anybody else got any drill tips?? |
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. |
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| Sch3mat1c |
| quote: | Originally posted by Peter Daniel
For your info, that's a German made, titanium drill set. |
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!
| quote: | 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. |
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! :bigeyes:
Tim |
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| Peter Daniel |
| quote: | Originally posted by Sch3mat1c
at 1,500 RPM drilling a 1/2" hole in say, bronze! :bigeyes:
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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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| officeboy |
Wouldn’t a pure titanium drill bit be way to soft to drill anything other then plastic?
I’ve always been partial to cobalt bits, but really for nothing other then the pretty blue shine. :clown: |
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| tiroth |
| I never thought I would see the day that someone would lecture Peter Daniel on how to machine metal. :whazzat: |
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| Peter Daniel |
| I'm using titunium bits for PCBs;) |
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| Magura |
Peter is right pretty much all the way....As Peter I too have all the cutting edge tools I could ever imagine...but for DIY handcrafting a usual cheapo HSS tool is mostly to be preferred, since most of the hardcore optimized tools are made for CNC machining....and may be even dangerous if used in a press drill or a handheld power drill. The sharpness of the optimized tools and the cutting angles are definitely no good for DIY....but naturally, if you got a CNC machining center or the like...theyre a bliss.
As for cutting speed...its really quite simple. For a reasonable quality of aluminium the recommended cutting speed for HSS is 60-90 metres per minute...the formula for this is :
cutting speed, divided by the diametre of the tool in milimetres, times 1000 divided by PI.
For aluminium the cutting fluid should be alcohol for drilling and tapping.
Theese guidelines goes as well for milling and turning.
Magura |
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| Peter Daniel |
Coming back to those infamed by Schematic DeWalt bits.
Most diy-ers here probably don't have much idea where to get proper tooling for, let's say, making recessed holes for Allen type screws. Even if they did, the pro bits would be much more expensive than stuff you can purchase in hardware store, like HD or Lowes.
I say again, DeWalt bits (Bullets) are the best choice not only for regular drilling, but also for more specialized type of holes. And if used properly, they last longer than you'll ever need them for. |
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| li_gangyi |
| sometimes when I wanna "drill" a tube socket hole...I just use a punch...I'm lazy... |
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| Sch3mat1c |
| quote: | Originally posted by Peter Daniel
That just confirms that you have no clue what you are talking about. No wonder your bits get dulled too early. |
I don't remember the exact feeds and speeds... I know the 1/4HP drill probably wouldn't handle it anyway, I had to step it down to 600RPM to get a good cut on steel with that bit.
| quote: | | But I also have some pure titanium drill bits. |
:bigeyes:
Tim, resident of rec.crafts.metalworking so tries to pretend to know at least a LITTLE about m/w... |
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| eStatic |
| quote: | Originally posted by Magura
...but for DIY handcrafting a usual cheapo HSS tool is mostly to be preferred, since most of the hardcore optimized tools are made for CNC machining....and may be even dangerous if used in a press drill or a handheld power drill.
...
For aluminium the cutting fluid should be alcohol for drilling and tapping.
Theese guidelines goes as well for milling and turning.
Magura |
Some questions from a wood-worker who has not much of a clue when it comes to metal:
I often use cobalt alloy end mills in my drill press on wood and Al. Is this dangerous?
I didn't know this but it's very good news to me as oil contamination of wood after milling or drilling Al has been an occasional problem for me. But there are a lot of different alcohols. Got any specific recommendations?
Thanks
eStatic
(sorry for all the posts but I'm laid up for a few days and this is a great place) |
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| Sch3mat1c |
Yes, very dangerous. :att'n: The taper which holds the chuck in place isn't made to handle sideways forces, nor are the bearings.
Sooner or later you'll have it come loose and a few pounds of spinning, flying chuck coming at you...
Tim |
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| Magura |
| quote: | Originally posted by eStatic
I didn't know this but it's very good news to me as oil contamination of wood after milling or drilling Al has been an occasional problem for me. But there are a lot of different alcohols. Got any specific recommendations?
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In the past ive tried different types of alcohol......anything from vodka to carburator liquid will cover your needs. dont use rum...thats vandalism
Magura :) |
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| lgreen |
Hey, that's all great advice, thanks everyone.
Actually, now might be a good time to mention that the shaft is going to both rotate and pivot vertically. So its going to be mounted on a hinge of some sort. So I guess I could drill a hole in a panel, mount the shaft, mount the panel on a hinge, and mount that inside the chassis, or I could just mount a pillow block on a hinge in the chassis.
Since this is DIY, I've stumbled across a sealed ball bearing shaft that I can mount onto a hinge, and it cost $.99. This is a little long (2") and complete overkill, it also requires me to make a custom bracket, but hey, that's what DIY is all about.
I'm probably going to try this out, you all can make fun of me later, when I post the completed project......if I ever finish! |
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| RIC |
| Get your old junk roller blades out and take a good once over at the bearings, thay come out fairly easy, and you might find what your looking for. |
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| li_gangyi |
No roller Blade is ever junk...I'm a rollerblading fan...hehe...I blade everydae...dun junk it...unless ur wheels are really worn out...seriously though...I think a plastic bush woulr really do well...you dun have to go all the way and use a ball race...if u're really despo and have some specs and stuff..I suggest you look at RS (radio Spares) not Radio-Shiok....Under Industrial Products you have a pretty good range of ball races and bearings...
www.rswww.com |
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