no keyway on driveshaft

[coastlogger]

Started to "rebearing" the driveshaft on my "FGM" 13 hp (was) manual mill.Driveshaft is about 18 inchesx 1.5 with 2 pillow block brgs, 8 inch 2 sheave pulley on one end, 19 inch bandwheel on other end. First remove bandwheel. Right. Its a taper fit hub with 2: 1/4 inch bolts to push hub frombandwheel. Turns out this is a VERY thin hub and it disintegrates under moderate force from bolts. No prob(I think) local NAPA say they have several of these paper thin hubs. Guess Ill buy 2.Anyhow the bandwheel and the belt pulley are both installed with taper fit hubs and no keyways. Seems like a problem waiting to happen to me. Anyone had experience with this? Is this a common way of doing this ordid my builder just takea shortcut here?(There has never been a hub slippage problem in the 12 years Ive owned mill) Im hoping to upgrade to a 20 hp diesel soon so will have way more torque to deal with then. Is the 1.5 inch driveshaft a pretty common size Im wondering.?Seems to me it probably is since the apparently widely used 19 inch pulley/bandwheel is set up for a 1.5 or smaller shaft it seems.Hoping to hear from you Frank C.
clgr.

[pineywoods]

The keyless hubs are pretty much an industry standard. Woodmizer uses them but I think it's a 2 inch shaft. 

[Cutting Edge]

Keyless Hubs actually are better than one with a key because they incorporate friction around the entire shaft surface.  No movement, safer, and less vibration.  Very handy if the application requires components to be "in time"

With a keyed shaft you rely on usually 2 set screws to supply the holding power.  Yes, they work, but over time the "slip" fit on the axle can "waller" (spelling?) itself and wear the keyway out of both the axle and pulley/sprocket.  Especially bad if it experiences directional changes or varying torque requirements.

[ladylake]

Those taper lock pulleys clamp on a shaft real tight, I like them.   Steve

[bandmiller2]

Coasty,those are probibly "H" series taperlocks and are not designed for a key.You are right at the upper limit of their range.I would replace the bolts with the best grade 8 bolts you can find or allen head cap screws,and tighten them well.The next series up taperlocks are keyed,but what you have should work. Frank C.

[coastlogger]

Thanks. Sounds like no key is std.The belt pulley hub on engine drive end does have a keyway for a shaft key, just no keyway in shaft.The hub to pulley taper has a key built into it. Bandwheel pulley/hub has no key at all. Thinking I need to assemble DRY to maximize friction, might heat up bandwheel in oven to create a bit of shrinkage. Thoughts anyone?The drive pulley has 3 :3/8 bolts to pull it together, but the bandwheel only has 2:1/4 bolts spaced 180* to pull it together.
clgr

[rmack]

what happens if you shrink it on tight, and get your alignment out, then gall the shaft trying to move the sheave afterwards?

any chance of that?

[GAB]

If the wheel heated to get a tighter fit is manufactured of cast material do not get it too hot, because when it cools the internal stresses created could be more than the casting is capable of safely handling and the results could be costly, and hopefully not deadly.
Safety should be everyone's number one priority.
GAB

[eastberkshirecustoms]

If your taper lock bushing has a provision for a key, as your drive pulley does, then you should have a corresponding key and keyway in the shaft. That particular style of bushing is designed around the use of a key. You will not get a 360° lock without it. If the bushings are designed without a key, as your bandwheels are, then you are fine. Depending on what style bushing (should be stamped), you might be able to swap out the keyed one for a keyless. You also need to make sure that you don't over torque the install bolts.
Here are the torque spec's for various style bushings: JA- 60, H- 95, SH- 108, SDS- 108, SK- 180, SF- 360.
These torque spec's are in.-lbs.

[eastberkshirecustoms]

I wanted to add that heating your bandwheel is a bad idea, especially to shrink it? Heating it will make it expand. Yes it will expand in all directions, but because the overall length (or diameter) has also increased in size, the diameter of the hole will be larger, not smaller. It is common practice to freeze shafts to shrink them for installation on a tight interference fit. You can also heat the the other component (bearing, pulley, gear, etc.) to expand it with the proper equipment and temperature, but as posted earlier, you need to use caution in doing so.

[coastlogger]

The idea was to heat the wheel uniformly to say 150 degrees F,thus expanding the pulley including the hole very slightly,then when it cools it would in effect shrink tighter on shaft.A similar idea to freezing the shaft but that is a bit harder to do as it is installed when wheel goes on. Could use an ice pack i guess.

[eastberkshirecustoms]

Ok, I see what you're saying now. Same thing I was. You want to be able to draw the taper lock bushing further into the pulley with it hot. Boy, you'd never get it back out though and it might just crack the cast housing.

[bandmiller2]

Coasty,your heat trick will work, probibly too well, and may cause problems down the line,not really needed.If you have a tapered bushing with a keyway slot but no slot on the shaft you can use whats called a dutchman.Thats sort of a catchall term like johnson bar.If a shaft and bushing have no keyway and are flush you drill say a 5/16" hole half in the shaft and half in the bushing and tap in a roll pin.You can always drill a hole perpendicular to the shaft and tap in a short roll pin then slide the keyed taperlock over it. Frank C.

[shelbycharger400]

what you should do,  is just have the pulley broached.  a .250 broach is about $100.  but you would need an arbor press,  and one to do the job costs about 3-500 used.    worse part about it,  it takes less than 10 minutes from setup to finished part, if you have the correct bushing for the hole. ..

[coastlogger]

EXCELLENT responses and a lot of wisdom thank you guys.Heres where Im at as of this moment. 1. Forget the heat 2. Possibly do a drill roll pin trick like Frank has suggested,on both pulley and bandwheel ends. Did find the "H" designation on the pulley so am confident in ordering a new hub.
Reason Im tackling all this by the way is that I started eating bands. 600 bf down from 2500 or so total band life.Meanwhile I had to take a shim out on my bandwheel driveshaft pillowblocks to maintain band alignment. Bearings feel fine but something must have caused this misalignment to occur and Im thinking it had to be wear in the bearings..Also the 2 "B" section drive belts were original and had worn down to the width of "A" belts. Possible vibration fr them too maybe Im thinking.Hopefully all this fooling around gets my band life back. Ordered new belts from "Princess Auto" where they sell of course made in China belts for a fraction of a Gates or whatever. May not have been a good idea. A "B" Belt from thjem,stamped with the B76 etc is NOT 79 inches as expected but is actually 77 inches.Grr. 2 Gates B76's being ordered tomorrow.
Can anyone confirm the shaft size on their mills with say 25 or more HP and 19 inch belted bandwheels?Still wondering if I can run my 20 hp diesel with the 1.5 inch shaft.
thx
clgr

[eastberkshirecustoms]

coastlogger, I can't help you with your shaft question. I can offer a suggestion on your belts though. IMO, you should be running a banded belt to get your smoothest, uniform operation. If you have to buy 'singles', at least make sure that they are matched belts- which may still have a variance of ±0.070" in length.
Also, you may not be able to feel the play or wear in the bearings by hand. They may well be bad under tension. You should check them with a dial indicator and a pry against the shaft.

[bandmiller2]

CLGR,I would not worry abut the HP increase,or do any changes to your shafts or taperlocks unless you have to.Unless your going to crowd your feed speed their won't be much more torque on the running gear, just won't droop under load as much. Chances are  the bearings are on their way out,if they are a name brand you can just replace the bearing not the whole housing.Name brand bearings cost more because their worth more,but thats your call,Hong Kong Harry bearings are tempting. Frank C.

[shelbycharger400]

china bearings are junk... no quality at all !
american made bearings... standard tolerance is one tenth of an inch
you will Pay for good bearings,  but you will pay over and over again with cheap ones too.

[rmack]

Yes it will expand in all directions, but because the overall length (or diameter) has also increased in size, the diameter of the hole will be larger, not smaller

i have worked with many shrunk on sheaves/sprockets, mostly 2" -6" shaft diameter.

an interference fit requires the inside diameter to be expanded prior to installation... heating of the sheave/sprocket is more common than cooling the shaft because of the general availability of oxy/acetylene, propane etc.

if you start from the inside of the sheave, the hole will expand inward, effectively reducing the id and making installation impossible... they have to be heated from the outside in, gradually, to either remove or install them. even then, there is usually a tapered pin driven into a keyway in both shaft and bore and it's generally easier to  move the sprocket away from the key than drive the key out of the sprocket.

i thought maybe the sheave could shrink on tight to the taperlock making fine tuning impossible... guess not though.

Coastlogger; just curious, what part of the island are you on?

[shelbycharger400]

just remembered,  i have used my toaster oven to preheat parts up to 400 degreese,   then broke out the oven gloves and a pliers and a prelit map gas torch.  it dose work
(had to put on a speedo gear on a 90's cheby 700r4)

[coastlogger]

Shelby..Here in Canada we dont have toaster ovens that will accomodate a 19 inch bandwheel.lol. However my wife does go off to meetings etc and a full sized kitchen oven is quite suitable. Just a scheduling thing.As I posted, I think now Ill try it with very little or no heating.
rmack Im near Port Hardy.

[shelbycharger400]

coastlogger... a buddy of mine has an old oven in his garage, just for preheating ... press parts, welding ect

[Al_Smith]

FWIW most of our DC servo motors on the CNC machines at work use keyless couplings .

[GAB]

Mr. shelbycharger400
Sir I think you meant 1 tenth of a thousands of an inch, and not a tenth of an inch which is .100" or more than 3/32".  That would be an awful lot of slop.
G