flywheel fixings

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max corrigan

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Can anyone point me to a thread concerning fixing flywheels other than the usual grub-screw method, i have tried search which brings no results!
This posting was only a couple of months ago, but i cannot find it for love nor money :( must be getting old!!
Regards Max...........
 

gbritnell

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Hi Max,
I don't know where the thread is but here's my take on what should be done.
Most steam engines run quite smoothly and therefore can survive with a grub screw or set screw into a recess in the crankshaft but with an IC engine you have variable oscillations, compression, ignition, that can make the screws come loose and worse yet make an ugly mess of the crankshaft.
My suggestion is to buy the appropriate keyway broach and broach out the flywheel. For an engine with a 4.00 (100.0mm) flywheel you can use a .093 (2.50mm) broach.
For the crankshaft you can use a full length slot cut with an endmill or just a local recess cut with a Woodruf key cutter. For smaller diameter crankshafts I would recommend using the end mill slot as the Woodruf cutter cuts fairly deep.
gbritnell
 

Niels Abildgaard

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Can we have a sketch or picture?
I am press fits fan.
For shafts You can always make it hollow to half the diameter without having to recalculate torsion and bending .Put a female thread in and make the hole in flywheel 3 parts per thousand less than outside of shaft .With a suitable bolt and nut pull the flywheel on and You have more torquability than Your engine can make without wringing crankshaft.
It is necessary to prepare the flywheel for being pulled of but without a picture no advice.
 

jonesie

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on my jerry howell farmboy , i am using a small 1/8 key and taper locks on on the shaft ends and seem to be working real good jonesie
 

Troutsqueezer

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Also, if you search YouTube for "broaching" there are videos showing how to do it. Some even show you how to make your own broaching tool (simple) and use your lathe to make the cut on the flywheel.
 

max corrigan

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GailInNM said:
Here is a link to a thread that discusses some options.
http://www.homemodelenginemachinist.com/index.php?topic=11471.0
Gail in NM
Gail that is the thread i was referring to, thank you everybody for your prompt replies, i think i might go along with Chuck's method with the parallel bush and integral split clamping collar on one side i don't trust myself making the tapered type! although it does look the business
Thanks everybody once again, that's what i love about this site, plenty of help and referrals :bow:
Regards Max.................
 

maverick

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Another method that is easy and will transmit quite a bit of torque is to set the crankshaft on end in the mill and with the flywheel in place,
drill and ream a hole on the interface between the shaft and flywheel. Press in a dowel pin or a length of drill rod and secure with a set screw.
This may not look quite as good from the end but eliminates the need for a broach and is quite strong.

Mike
 

Joachim Steinke

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Hi Max

Here is another well proven method for fixing any sort of wheel/disk//flywheel to a plain drive shaft.





When using this collet style insert the shaft can stay plain without any threading, taper or pin bores. The collet creates a really strong fixation, even for highly alternating loads and strong vibrations that might come from an IC engine.

If the cone fitting is build thoroughly you will get a perfect true running, even after a lot of disassembling. I used this type of fixation really often and it never failed.

The only handicap of (all) this type of pure clamping systems a not automatically fixed orientation (meaning the rotating position) between shaft and wheel, so it is no good choice for flywheels carrying ignition contacts or other related items.

This is a photo showing an assembly I have made for some other purpose (a quick removable table handle), didn’t found an appropriate picture in a rush, but the principle is the same as for any model engine.





Achim
 
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