Flywheel machining

[TAftonomos]

So I finished up the other side/strut for the bobber, and decided to remove the stock exhaust.  one stud broke off flush in the head, others came out no problem.  I drilled the thing dead center with a cobalt bit, then used an extractor....which broke off in the hole.  After mucking it up with a cobalt die grinder, I decided the head will probably have to come off and be milled out.  No big deal as the motor has to come out anyway so the frame can get powdercoated, but still...grrr...   

Anyone know of a drill bit that can drill out an extractor?

I got tired of stuff breaking on that old suzuki, so I machined another flywheel 



Takes a bit over an hour to machine one down as my machine isn't CNC. 

[kopfjäger]

Nice job. 

[sno_duc]

So I finished up the other side/strut for the bobber, and decided to remove the stock exhaust.  one stud broke off flush in the head, others came out no problem.  I drilled the thing dead center with a cobalt bit, then used an extractor....which broke off in the hole.  After mucking it up with a cobalt die grinder, I decided the head will probably have to come off and be milled out.  No big deal as the motor has to come out anyway so the frame can get powdercoated, but still...grrr...   

Anyone know of a drill bit that can drill out an extractor?

I got tired of stuff breaking on that old suzuki, so I machined another flywheel 



Takes a bit over an hour to machine one down as my machine isn't CNC. 

I started my machinist apprenticeship May 1st 1978.

A few comments.
Aloris toolholder 
Tool up tight to the toolholder 
Part tight to the chuck 
Speed a little fast ( chip color, should be blue/purple with orange/brown streaks, yours are purple/white)
Feed rate too slow ( propably about 0.002--0.004 per rev should be in the 0.006-->0.010 range, look in the carbide insert catalog, their speed/feed charts are a great starting point. When things are right you don't get 'Bird's nests', you get 6's and 9's )
Depth of cut- was that your finish cut?? If not your set-up is good, the worst that can happen is you stall the spindle. ( I did blow the the motor-overloads once on a 75hp Bullard, of course I was taking 0.800 on a side at 0.010/rev in 8620. It sounded like a hail storm )
The ' Machinery Handbook ' speed/feed charts are also a good starting point.

[scduc]

[
Depth of cut- was that your finish cut?? If not your set-up is good, the worst that can happen is you stall the spindle. ( I did blow the the motor-overloads once on a 75hp .

[/quote]Thats not really the worst that can happen. I've seen parts come flying out of the chuck and end up on the other side of the shop. The lathe is by far one of the most dangerous tools. My old tool maker freinds have told me many of stories of people getting wrecked on lathes and simple drill press.

[TAftonomos]

Thanks Sno-Duc, I definatly need some coaching/teaching for this thing.  I wrecked a few of the carbide inserts early on when I started trying to machine some stainless and took too big of a bite out of it.  I guess I was trying to take less.

You were about dead on on the feed rate though, I've got the machine turned WAAAY down on that gear box.  I need some sort of RPM gauge though, I've got no idea what it is.  I can vary the Hz to the motor with the VFD which is nifty....if I only knew what speed it was going (was flat out when I cut those). 

Easy lesson learned early....1018 cuts easier than 304 

[Langanobob]

Anyone know of a drill bit that can drill out an extractor?

I don't.  If you've got the head off you can try heating the stud, that sometimes destroys the Loctite or corrosion that caused it to stick in the first place.  If you can heat the stud and embedded extractor red hot and protect them so they cool slowly you will more or less anneal and soften the extractor and possible make it drillable. As long as you're careful not to get things so  hot that you damage the head.  Then if you can cut a screwdriver slot with a die grinder or Dremel they sometimes will come out.  But it sounds like you already tried the die grinder.

If all else fails, I think some machine shops have some sort of EDM device that can "dissolve" the stud without damaging the head, but no FHE.

Good job with that old lathe. 

[sno_duc]

[
Depth of cut- was that your finish cut?? If not your set-up is good, the worst that can happen is you stall the spindle. ( I did blow the the motor-overloads once on a 75hp .

Thats not really the worst that can happen. I've seen parts come flying out of the chuck and end up on the other side of the shop. The lathe is by far one of the most dangerous tools. My old tool maker freinds have told me many of stories of people getting wrecked on lathes and simple drill press.

I worked in one shop were make the beast with two backsing your brother was the name of the game. If you went to the bathroom, you'd best check every bolt, camlock, vice, toolholder......lest one of your co-workers "help" you. Wanna know how to cut a bannana shaped keyway.... loosen the over-arm clamps on a BridgePort style mill. Ask me how I know  . First rule don't get mad. Second rule look for the guy who isn't busting up laughing...He's the SOB. Did you know that # 12 sheet metal screws fit nicely between the door and frame of a locker ( about 4 dozen ). ( see rule two ) I once saw a 16" chuck accidently 'fall' of a lathe, made a one hell of a noise when it hit the wall. ( camlocks "loosened" up over lunch ) Another fun one was to adjust your 'friends' micrometer so it reads 0.002--0.003 big. Throwing parts out of the chuck aint no thing, you know if you a have good setup or not. If not stand off to the side.

TAftonomos if you don't have one invest in a "Machinery's Handbook" the speeds/feeds charts are great starting points. Adjust from there. Small adjustments. The last job shop I work in, we would take weeks massaging CNC programs try to get the perfect balance between time of operation and tool life. Speeds / feeds / depth of cut  and which coolant are where it's at. You'll learn.

[brad black]

turn the flywheel around and machine the outer down to 120mm diameter and go in about 13mm from the leading edge.  that spin it around to how you have it in the photo and machining from the centre of the relieved section take out the inner diameter until it's about 121mm, cuting radially outward in small cuts.  eventually you'll go thru to where you did the outer and a steel ring will fall off.  saves machining time quite a it.  i have a small lathe and can do them quite quick.  i spin mine around 250rpm from memory, and it seems a nice speed.

if you're using carbide bits once they start glowing red they're rooted.  throw it away and fit another.  a good bit cuts down on time too noticeably.

[RB]

my suggestion for removing the stuck bolt/extractor involves a welder, a washer, and nut.
Spot weld a washer to the broken bolt(fill in the hole in the washer, this will concentrate heat to the bolt). now weld a nut to the washer, fit wrench and , hopefully while hot, twist the bolt out. i have used this method dozens of times, and i can't think of anytime this didn't work....hope it works for you.

good luck, and nice job on the flywheel.

RB

[Langanobob]

my suggestion for removing the stuck bolt/extractor involves a welder, a washer, and nut.
Spot weld a washer to the broken bolt(fill in the hole in the washer, this will concentrate heat to the bolt). now weld a nut to the washer, fit wrench and , hopefully while hot, twist the bolt out. i have used this method dozens of times, and i can't think of anytime this didn't work....hope it works for you.

good luck, and nice job on the flywheel.

RB

Sounds like a very good method.  Anyone who owns a lathe should also own a welder.