In english please!

Hi everyone....

I'm trying to find out what the name of the application, from the link, in english?

http://www.quimatic.com.br/images/plasteel/img_plas_32.jpg

I'm trying to find a shaft with that "extra square" on it!

Hi everyone....

I'm trying to find out what the name of the application, from the link, in english?

http://www.quimatic.com.br/images/plasteel/img_plas_32.jpg

I'm trying to find a shaft with that "extra square" on it!

You mean a shaft machined with a keyway. Or a "keyed shaft".

Its called a Woodruff Key

Its called a Woodruff Key

No it's not. A woodruff key is semi circular on the back and usually used as a secondary location on a taper.

The illustration is a standard square shaft key.

How can you tell what the back is like from that shot? Its a woodruff key I say. :-)

The illustration is a standard square shaft key.

Being really pedantic, the key shown appears to be wider than it is deep, so it's a rectangular or parallel key, not a square key.....

......I'll get me coat! ;)

usually used as a secondary location on a taper.


sorry got to disagree there, in automotive applications at least it apart from steering box drop arms and diesel injector pumps most keyways are on straight shafts.

i believe the correct term were all looking for is a "machine key"

How can you tell what the back is like from that shot? Its a woodruff key I say. :-)

looking at the pic again i cant help but agree Al

Thanks guys....

Now another question! My though is that I will have to weld a woodruff key on a keyed shaft! right? Or can I find this already done?

No the key is not welded on. The "fit" of the key in the shaft can vary. If it is a "clearance" fit it will be slightly loose and you'll probably need a dab of grease to keep it in place, and preferably keep it on top of the shaft, while you fit the collar/pulley. If its a "tight" fit (not the correct engineering term, but I can't remember it off hand) then it should just knock into the shaft with a soft mallet and stay there by itself. If its and "interference" fit, you'll need to cool the key and warm the shaft up to get it in, then when the temperatures equalise it'll be in for good. :-)

DIN Standard 6888 covers Woodruff keys and gives details of all standard sizes, including the radius of the curved back and the height of the segment. It also confirms that it is normally used for positioning rather than transmission, unless the key is very large in relation to the shaft. e.g. a key 10mm long, 4mm deep would only be used for transmission on an 8-10mm diameter shaft.

If the shaft were, say 30mm in diameter, you would be looking at a 30mm x 13mm key, much deeper than a parallel key would need to be.

You can see that that is not a Woodruff in the pic because a Woodruff comes to a sharp edge as it emerges from the keyway, being a segment of a circle. You wouldn't put a Woodruff on the end of a shaft like that either.

As for being square or rectangular, Parallel keys can be square or rectangular. I appreciate we are only looking at a schematic but, taking the depth of the key into the shaft and the depth of the keyway in the bore, that's square.

it should be noted that the point of these keys is only to locate, not take the drive, its quite common now days for car manufactures not to use keys at all, if they have some other means to align shafts and sprockets etc, whatever goes on the shaft should be clamped tight by someother means.

i have seen many a worn crankshaft and pulley due to the front pulley nut only being nipped up in the false belief that the key does the driving

Its called a Woodruff Key
Deffo not a woodruff key, woodruff keys are never cut into the open end of a shaft, For me its a parralell key, or it was when I did my time as an engineer.
Ian

woodruff keys are for location only, as an example Lambretta and Vespa both uise them on the crankshaft to position the flywheel ( magneto ignition, therefore position is important) the weight of the flywheel means its strength in position is by torquing the bolt up as the shaft and flywheel boss are tapered and therefore lock.

that picture is a parralel key way, oftern seen on shaft drives with a taper lock pulley ( think giant pumps/motor drives ) there is a standard for keyway size and Shaft diameter, but the name escapes me at the moment.

I can't remember everything !!!

Select a file of the correct width, gouge out a matching keyway until bored or totally knackered, assemble on shaft, bang in the tang of the same file, break it off....job done....Judging by the thread starter's name this is the sort of advice he is looking for ;)

Select a file of the correct width, gouge out a matching keyway until bored or totally knackered, assemble on shaft, bang in the tang of the same file, break it off....job done....Judging by the thread starter's name this is the sort of advice he is looking for ;)

Still keeping the engineering skills up then Steve! :rofl:

Select a file of the correct width, gouge out a matching keyway until bored or totally knackered, assemble on shaft, bang in the tang of the same file, break it off....job done....Judging by the thread starter's name this is the sort of advice he is looking for ;)

did you do an apprentiship at British Leyland per chance ?


http://gallery.slacker.com/albums/tboicey_comics/sst.gif

did you do an apprentiship at British Leyland per chance ?


http://gallery.slacker.com/albums/tboicey_comics/sst.gif

I see you have discovered the 'Fine Tuner"
:rotate:

I see you have discovered the 'Fine Tuner"
:rotate:

aka 'Birmingham screwdriver' - or, to those of us who served our time in Yorkshire, a 'Manchester screwdriver'.

Still keeping the engineering skills up then Steve! :rofl:
Hello Alan...Haven't seen you since you were on TV looking suitably surprised while the Fuzz explained the nuances of vin numbers :rofl:
It is good to see you are rebuilding the PRS...a few of the Classic guys may be turning out in the NW so you would be in good company....any further technical tips you may need, all from the 'Rock Ape' school of enginooering...feel free to ask...Steve.

Hello Alan...Haven't seen you since you were on TV looking suitably surprised while the Fuzz explained the nuances of vin numbers :rofl:


You saw that as well - My 10 minutes of fame.

Trying to get the PRS sorted out. The engine is in Andrews garage waiting to find out if the crank that Brian Mullarkey gave us about 15 years ago is still crack free. The gearbox is sitting in my garage gathering dust on the floor. We'll get there eventually!

Will try and get to Oulton or Anglesey this year just to say hello if nothing esle!

Deffo not a woodruff key, woodruff keys are never cut into the open end of a shaft, For me its a parralell key, or it was when I did my time as an engineer.
Ian

Have you never removed the flywheel from a Briggs & Stratton engine?
There's a woodruff key in there.

The drawing, being a solid rendering, does not show any detail in the keyway, which could be cut with a semi-circular depth groove for a woodruff key.

And they are used for drive, unless they are used for location, when coupled with a tapered shaft (a la Villiers 2 stroke), then done up f tight.

If it were a parallel key, they are usually coupled up with a retainer of some type, such as a nut/washer on the end of the shaft to stop them coming out.
Quite often, parallel keys have a lump on the end (for whacking it with the official club hammer)

dtype38, I think the term you were looking for was "Engineering Fit", which is how it was explained to me by my machine shop lecturer. Clearance fit would rattle, Engineering Fit fitted with no appreciable slop, and interference fit needed to be clobbered with a ruddy great hammer and a drift!

Rob.

The harmonic balancer on a V8 Chevy engine fits to the end of the crankshaft with the help of a Woodruff key. The piece is a tight fit and it is recommended to warm it a bit then give it a tap on using a heavy piece of steel against it to protect it from damage. The actual bolt holding it on (well it doesnt actually it is the shrink fit that is holding it on) is a weak little 5/8 UNF bolt and I suspect it is more there to help you turn the motor over with a spanner than anything else.

The drawing, being a solid rendering, does not show any detail in the keyway, which could be cut with a semi-circular depth groove for a woodruff key.

It shows an open-ended keyway, which is never used with a Woodruff key.

Ok so now a second question!

Does anyone know a site online where I can buy a keyed shaft....metric?

Or....does anyone have a 15 mm (diametre) keyed shaft? ....I only need a 20 cm long shaft! It will be cut in 2 to make a part I need for a prototype I'm building for the Shell Eco Marathon! My budget is only 500 euros...I'm a privateer...when my university for example has spent over 40thousand euros in the last 4 years....so if anyone has a keyed shaft the can give me? (I'll pay the postage)

have you fellow single seater drivers never stripped your dry sump oil pumps. Each lobe is driven by a woodruff key. I must admit, they seem to get pretty slack over a period of time, so suggesting it probably isn't the best system.
I also don't recall a woodruff key slot opening out of the end of a shaft, it would to a large extent reduce it's function.

Ok so now a second question!

Does anyone know a site online where I can buy a keyed shaft....metric?

Or....does anyone have a 15 mm (diametre) keyed shaft? ....I only need a 20 cm long shaft! It will be cut in 2 to make a part I need for a prototype I'm building for the Shell Eco Marathon! My budget is only 500 euros...I'm a privateer...when my university for example has spent over 40thousand euros in the last 4 years....so if anyone has a keyed shaft the can give me? (I'll pay the postage)
Without knowing the application it is hard to advise, but a keyway on a shaft only 15mm diameter is going to be pretty flimsy and not transmit much power. A cotter pin as on the crank of an old pushbike is very strong and the flat on the shaft can be filed by hand.

Ok so now a second question!

Does anyone know a site online where I can buy a keyed shaft....metric?

)

got access to a lathe that would hold your shaft?

if you have then make your own keyway, hold the shaft between head and tail stocks, locking the headstock off so it cant rotate, and mount a suitable cutting bit in the tool post in such a manor that it would cut the shaft as you wind the apron up and down the bed.


failing that most decent old fashoned engineering works should be able to do it for you

if you have then make your own keyway, hold the shaft between head and tail stocks, locking the headstock off so it cant rotate, and mount a suitable cutting bit in the tool post in such a manor that it would cut the shaft as you wind the apron up and down the bed.

.....or use a vertical milling machine.

Without knowing the application it is hard to advise, but a keyway on a shaft only 15mm diameter is going to be pretty flimsy and not transmit much power.

If the key's long enough the shaft will fail in torsion before the key shears.

I'm sure your right Dave but with say a 6mm key the effective diameter will be down to 12mm. As you will have gathered I'm not a big fan of keys

If the key's long enough the shaft will fail in torsion before the key shears.
That's surprising! I always thought that the whole point of a key of the correct size and material was that it would shear and remove the drive from the shaft before the shaft failed in torsion. :)

d type you would use a shear pin for that, the key is only supposed to locate not take the drive

See your point, and agree for Woodruf keys and taper shafts, but I've seen keyed pulleys on parallel shafts which were only retained with a small screw and large washer on the end of the shaft. I'm pretty sure they were using the key for the drive...

I cant beleive how much interest this has generated!! You guys should be ashamed :p

This thread has had 588 views, so it can't be that boring. If you want more excitement, may I suggest the F1 forum ;)

This thread has had 588 views, so it can't be that boring. If you want more excitement, may I suggest the F1 forum ;)

'Excitement', 'F1'.....now there's words you don't very often see in the same sentence!

As you will have gathered I'm not a big fan of keys

Depends on the application - if it's stock motors, gearboxes, couplings, etc., which come already keywayed, might as well use a key. If not, Taperlocks, Rollpins, etc., all have their part to play.

See your point, and agree for Woodruf keys and taper shafts, but I've seen keyed pulleys on parallel shafts which were only retained with a small screw and large washer on the end of the shaft. I'm pretty sure they were using the key for the drive...

Parallel keys are often used to drive. Woodruff occasionally.

Anyone who thinks parallel keys aren't used to drive has clearly never had a kart, have they? Or used an industrial electric motor?

industrial electic motors are rather different in that they produce a steady torque totally different to whats found in most automotive applications even then i think you find that they are mostly used inconjuntion with some other means to grip the shaft rather than purely relying on the key

The harmonic damper on the Small Block Chevy which is 'located' by the key because it has to go in one position so you can time the engine, as I said though it is fitted by warming and I don't think there are shear loads on the key as such and yes it is more interesting and exciting than F1 but then again so is watching paint dry!

industrial electic motors are rather different in that they produce a steady torque totally different to whats found in most automotive applications even then i think you find that they are mostly used inconjuntion with some other means to grip the shaft rather than purely relying on the key

In many industrial applications the load varies greatly, much more so than in any automotive application, & shock loads can be experienced. Pulleys, couplings, etc, are commonly retained on the shaft by grub screws clamping down onto the key. Gib head keys perform a dual function - they not only transmit torque, they also lock the hub onto the shaft.

I'm with Dave on this one.... you wouldn't say electric motor shafts don't take load if you'd ever seen a 100hp 4pole motor start up direct-on-line! It can itself and equipment attached up to 1400rpm in less than a second... that equates to a pretty powerful car engine. :-)

Digressing slightly, It is common practice to remove the dowel locating the cam sprocket on a FF1600 engine and rely on friction to locate....Surprisingly I have never had one move.

i'm not suprised at all! i've been doing that with 8,000 rpm beemers for years, thats how lots of modern twin cams and diesels are done. after all thats how most vernier pulleys work,

we use electric DC motors to replicate a caterpillar engine on our gearbox test rigs... programmed to do similar things to an engine!! they are 100BHp motors too.
also keyed!! then to a prop shaft, then to the gearbox. (brilliant design... mine!!!)

you design the size of the shaft much bigger than you need... they keyway is decided by some BS standard.

But don't electric motors lack torque and is'nt it the torque what will do the shearing not the power.

But don't electric motors lack torque and is'nt it the torque what will do the shearing not the power.

Electric motors produce a lot of torque at low speeds, even at zero rev/min. Industrial motors, in the smaller sizes which I'm most familiar with, run at 1,440 or 2,880 rev/min, very low speeds by internal combustion standards.

DC motors produce lots of torque at very low revs.
currently doing a quote for a company who makes water pumps, they need 1000Nm @ 750 rpm!
ok thats a motor and a gearbox, but u get the idea.
DC motors can run at high speeds with out many problems... last one i bought was 2500rpm at over run and 1600rpm at full power, 17kW i think, 150Nm.

servor motors run at higher speeds.. 5000rpm.. but lower Nm.. but usually have say a 40:1 gearbox on, which increases the torque.

But don't electric motors lack torque and is'nt it the torque what will do the shearing not the power.
Power does not exist except as an abstract expression of torque over time.Electric motors like steam engines and humans on pushbikes can deliver high torque from stopped.

I like StephenRae's idea of adapting a bicycle cotter pin as it can take a lot of torque as it seems to combine a taper and keyway in one,and is easily removed or replaced cheaply.

and the bolts come undone, they work them selves loose and trash everything. at least every push bike I ever had with them did

the square taper idea works a bit better, but still works loose

But don't electric motors lack torque and is'nt it the torque what will do the shearing not the power.

i also suspect that electric motors are not as violent in terms of snatching the load on and off

a bicycle cotter pin as it can take a lot of torque as it seems to combine a taper and keyway in one,and is easily removed or replaced cheaply.

not so sure about easily removed, every one i ever had to remove needed drilling out

not so sure about easily removed, every one i ever had to remove needed drilling out

after you'd turned the threaded end in to a dome headed rivet with an engineers persuador trying to free it :rofl:

not so sure about easily removed, every one i ever had to remove needed drilling out

I'm thinking of the bicycle crank cotter pin
which you lined up,tapped in then firmly tightened the nut onto the spring washer. Eventually daily use would loosen and take the edges off the taper and you tapped it out and put in a new one.I think doing these simple things as a 13yo led me to climbing under cars for life!!

Don't know when you would drill one out though.

As we are wandering off on tangents...it used to be common practice to have locking tabs on the big end bolts of Jags and BMC stuff...what changed apart from engines running smoother... threads are threads...maybe they were never needed.

And on that particular tangential note, I think we've wandered far enough to bring this one to a close. :)