ST15/20 shaft too long?

[dmarkh]

I'm considering changing out my ST10 for an ST15. My genset is in an enclosure on a trailer. Space has been pretty much pre-defined by the DIY'r that I inherited it from. The ST15 is 50mm (~2") longer than the ST10. This is at least 1" more than I have space for in the enclosure. I was wondering about the possibility of shortening the shaft on the new ST15 by a couple of inches. Here is the current connection using a LOVEJOY coupler. At least I'm hoping the picture will show up. There is quit a bit of wasted space on this shaft. Am I nuts?

Thanks
Mark

[vdubnut62]

No, I don't think you're nuts, but my opinion is not worth much since I missed my degree by a couple of grade points. I see no reason why it can't be done.
If it was mine and I wanted it shorter, then I would have at it.
You could probably even hacksaw or sawzall it off if you were really careful and didn't plan to let anyone see the raw end . Oh well, I will probably catch a LOT of flack over this,
but the Devil with 'em.
Ron.

[Carlb]

angle grinder and cutoff wheel is what i would use.  just make sure you have enough shaft when you are done for the coupler.

[dmarkh]

angle grinder and cutoff wheel is what i would use.  just make sure you have enough shaft when you are done for the coupler.

I wonder, I have a 14" chop saw. Might that also work? I also wonder if this shaft is "hardened" in any way or will it cut pretty easily?

Mark

[mike90045]

Chuck an abrasive disk in a vise, start the engine and approach the spinning shaft with the disk-in-vise,  watch out at the final cut the chunk of shaft comes loose.
Or this is a bad idea ?

[Carlb]

Chuck an abrasive disk in a vise, start the engine and approach the spinning shaft with the disk-in-vise,  watch out at the final cut the chunk of shaft comes loose.
Or this is a bad idea ?

I think he wants to cut the shaft on the gen head not the engine.   I have shortened engine shafts with the engine running at idle and an angle grinder with a cutoff wheel.   Works great and you get a nice clean cut.

[dmarkh]

I think he wants to cut the shaft on the gen head not the engine.   I have shortened engine shafts with the engine running at idle and an angle grinder with a cutoff wheel.   Works great and you get a nice clean cut.

That's correct. From the gen head not the engine. Good idea though.

Mark

[vdubnut62]

From what I remember, the ST shaft is mild steel, not heat treated or hardened. The chop saw would work, but do you have any idea what the rotor weighs? I would guess somewhere upwards of a hundred pounds. You could always fab up a quick and dirty cradle of some sort out of wood I suppose. Wood would be fairly easy on windings and such.
Ron.

[dmarkh]

From what I remember, the ST shaft is mild steel, not heat treated or hardened. The chop saw would work, but do you have any idea what the rotor weighs? I would guess somewhere upwards of a hundred pounds. You could always fab up a quick and dirty cradle of some sort out of wood I suppose. Wood would be fairly easy on windings and such.
Ron.

I'm thinking I can do it without removing it from the gen. I have an adjustable(height wise) 3'x5' steel table with wheels. We use it at work to install old heavy electronics devices into large steel cabinets. I figure I can set the gen head on it and then adjust it to my chop saw sitting at the end of a work bench. The chop saw blade on my unit is around 2" from the end of it's base so I'm thinking it should reach past the blade far enough for an inch or two cut.

Do you think it would be a bad idea to NOT remove it from the gen if I don't have to. Heat? Vibration?  I certainly don't want to damage anything. If it's not hardened though, should it not cut like butter and then not generate too much heat?

Thanks
Mark

[rcavictim]

With the ST-15 gen head on the floor or convenient open work surface, attach a hand held, variable speed (important)  power drill's chuck to the end of the generator shaft with some 2" duct tape which will work as a temporary coupling.  The OD of a typical 3/8" or 1/2" drill chuck will be close enough to the gen shaft diameter to allow flexible tape to bridge the gap. Open the drill Jacob's chuck fully so the three pincers are fully recessed, allowing the chuck to get as close as possible to the end of the generator shaft.  Have a friend steady and operate this drill to gently spin up the generator shaft (so as to not overtorque the tape coupler whilst getting the thing up to a goodly speed), while you cut it off at the right spot along it's length with a thin cutoff abrasive wheel in a handheld angle grinder. 

Make sure the key is removed from the keyway in the shaft.  Cut that to required length separately.

You will not heat the generator shaft to the point of damaging the bearing or anything else.  If you start melting the tape coupling take a break and let things cool.  You could have a container full of ice cold water at hand to keep this shaft cool (recommended).

This is how I would tackle this job.  No need to remove the armature from the ST-head.

If I didn't have these two power tools. I'd just use a hacksaw.  The shaft is soft enough.  If your cut is not outrageously out of true, the Lovejoy coupler will hide the evidence with no problems.  You could use technique to use the blade itself to get the shaft rotating, making use of flywheel action of the armature to keep it spinning.  This will encourage a nearly perfect straight perpendicular cut.

A friend could be employed with the 'no power tools' hacksaw technique to keep the shaft spinning with a piece of cord wrapped around the shaft, and modulated back and forth.

Good luck!

[Tom T]

A Porta Band Saw works good and no heat build up.

[rcavictim]

A Porta Band Saw works good and no heat build up.

That is a tool I have never owned or had the experience of using.  I own three floor standing bandsaws, but not a portable.  I have seen them occasionally on sale at Princess Auto.

I cut a 1" diameter mild steel shaft with a cutoff wheel on an angle grinder out in the yard just yesterday and it didn't get the metal all that hot thanx to the heatsink action of the mass of the shaft.

[Tom Reed]

If your gon'na spin it just use a hand hack saw and work it back and forth to keep the chips cleared. Good to see ya around RCA.

[rcavictim]

If your gon'na spin it just use a hand hack saw and work it back and forth to keep the chips cleared. Good to see ya around RCA.

Thanx for the welcome Tom.   If you do this outside I say let the chips fall where they may.  Haha.

[dmarkh]

OK, I finally got the ST15 and set up with a standard portable 14" chop saw to cut this thing. I started on it and quickly realized this wasn't going well. I got me a magnet and sure enough this thing has a stainless steel 48mm shaft. How do I cut a 48mm stainless shaft? I see some very expensive "stainless cutting blades". Is that going to be my only option?

My ST10 shaft is rusty so I never even though I might have trouble cutting the ST15. Any one have any ideas that might help me out with this thing?

Thanks
Mark