best way to cut polyurethane

[b20a86lude]

i was wondering wats the best way to cut polyurethane bushings from energy suspension thnx for help.

[lostforawhile]

i was wondering wats the best way to cut polyurethane bushings from energy suspension thnx for help.

lathe, kind of hard to do on a sander, they melt, cut some down years ago to make my front sway bar bushings. stuff is a pain to work with.

[Hauntd ca3]

if you freeze it good and proper first, it makes it far easier to do anything with.
just have to be quick before it thaws and gets soft again

[Civic Accord Honda]

i would think a dremel would work tho never worked with it so couldnt say for sure
ive used a knife to cut up rubber bushings tho au

[89T]

i use a drill press as a lathe. lol. it works

[Rendon LX-i]

a mini tourch...just like i did to removal the lower rear shock bushing and it pushed out like a smoor.....melts it like butter..thats only if your trying to removal it

[cygnus x-1]

Depends on what you want to do. If you just need to cut it in half or something simple then a sharp knife might work. Or if you need to machine it then freeze it in dry ice. And use a compressed CO2 blast to keep it cold longer. It might be mill-able too with really sharp tools if you can find a way to hold it down.

C|

[2oodoor]

mini torch and heat the blade of a utility knife or other knife

[Ichiban]

We machine polyethylene, which is a bit more rigid than polyurethane, but still sort of squishy. I've also machined rubber, which is quite a bitch. I've milled it with carbide and high speed steel end mills, but the best way to turn it is to use extremely sharp HSS with tons of rake and relief, a large nose radius, and moderately light cuts. Chucking and holding the material can be a challenge, as it readily changes shape and likes to bugger off under tool pressure.

[Tomisimo]

lol.. what a thread..

[lostforawhile]

We machine polyethylene, which is a bit more rigid than polyurethane, but still sort of squishy. I've also machined rubber, which is quite a bitch. I've milled it with carbide and high speed steel end mills, but the best way to turn it is to use extremely sharp HSS with tons of rake and relief, a large nose radius, and moderately light cuts. Chucking and holding the material can be a challenge, as it readily changes shape and likes to bugger off under tool pressure.

I put it in the lathe then notched it with a cut off tool,and cut it off holding a hacksaw blade while it was turning makes a mess too.

[Ichiban]

I put it in the lathe then notched it with a cut off tool,and cut it off holding a hacksaw blade while it was turning makes a mess too.

I can well imagine.

We machine this crap called Nylatron, it makes the stupidest floaty stringy rats nest chips you can imagine. Go too fast and it melts.

[2ndGenGuy]

Yay melty twisty burney plastic shavings! Must be fun in your eye!

[LX-incredible]

What exactly are you modifying the bushings to fit?

[cygnus x-1]

I can well imagine.

We machine this crap called Nylatron, it makes the stupidest floaty stringy rats nest chips you can imagine. Go too fast and it melts.

Nylatron. I'll remember that. Is it anything like oil filled nylon? I milled some of that a few weeks ago. Went ok with nice sharp tools. Except that it has lots of internal stresses so it warps like a mofo. Was milling PVC today. I quickly discovered the trick for that is low speed and high feed. Otherwise it just melts into a big wad of goo. And it smells horrible.

C|

[Ichiban]

Nylatron. I'll remember that. Is it anything like oil filled nylon? I milled some of that a few weeks ago. Went ok with nice sharp tools. Except that it has lots of internal stresses so it warps like a mofo. Was milling PVC today. I quickly discovered the trick for that is low speed and high feed. Otherwise it just melts into a big wad of goo. And it smells horrible.

C|

Good christ does PVC ever stink. Last week I had to bore out some sort of housings (x3 of them) to press in some nylon sleeves that were machined at some other shop. The smart ass manager at the shop tells me to measure each sleeve, and make the housing a .001 press fit. Except each sleeve runs out .02-.03 on the OD. And one is clearly .01-.015 under the size on the print. Not what I wanted on a Friday afternoon.

Turns out if the nylon bushing is a little tight, the edge of the metal housing shaves it to size before it enters the bore.

[b20a86lude]

wow guys amazing respones. thnx i got lots of ideas now
also im modfyin a strut bushing thats tad to big and i need like a inch off of it .

[lostforawhile]

Yay melty twisty burney plastic shavings! Must be fun in your eye!

ought to try these hardened castings for my forks, cut with carbide specialty inserts with no coolant,have scars all over my arms from burns http://www.youtube.com/watch?v=cEwPL0ogjLw

[Ichiban]

ought to try these hardened castings for my forks, cut with carbide specialty inserts with no coolant,have scars all over my arms from burns http://www.youtube.com/watch?v=cEwPL0ogjLw

Seen it.

I should post up a video of roughing on a lathe at work, it's the orange Csepel I posted pictures of earlier, taking .7" off per side makes some pretty amazing chips. Got scars from that too. I was threading on it one day, and a chip popped off the tool, hit me in the mouth, stuck to both my lips, and burnt my tongue trying to push the thing off my lips.

[Ichiban]

Nylatron. I'll remember that. Is it anything like oil filled nylon? I milled some of that a few weeks ago. Went ok with nice sharp tools. Except that it has lots of internal stresses so it warps like a mofo. Was milling PVC today. I quickly discovered the trick for that is low speed and high feed. Otherwise it just melts into a big wad of goo. And it smells horrible.

C|

It's dry. Full of Moly powder I believe.

[lostforawhile]

Seen it.

I should post up a video of roughing on a lathe at work, it's the orange Csepel I posted pictures of earlier, taking .7" off per side makes some pretty amazing chips. Got scars from that too. I was threading on it one day, and a chip popped off the tool, hit me in the mouth, stuck to both my lips, and burnt my tongue trying to push the thing off my lips.

been there done that, not as bad as the time that piece of metal i had cut off with the angle grinder, cut it off slapped my hat back on and the hot piece of metal was in my hat. had a burn on my forhead for weeks after that.

[2drSE-i]

So just out of curiousities sake, Cygnus have you ever tried to make your own performance bushings at work? Sounds like you've got some awesome material to play with, you know......when you dont have like uh....work to do.

[cygnus x-1]

It's dry. Full of Moly powder I believe.

Oh, ok. MDS filled. I have a sample of some of that but never used it. I have turned nylon though, and it does suck. At least with milling you get lots of little tiny tough stringy chips, that are easy to blow away. With turning you get one giant tough stringy chip that wants to take over the world, and has the ability to do it.

So just out of curiousities sake, Cygnus have you ever tried to make your own performance bushings at work? Sounds like you've got some awesome material to play with, you know......when you dont have like uh....work to do.

Seems like all I ever do is work right now. It just never seems to translate into very much money. But that's life when you're a small operation.

Never tried to make any performance bushings. It would be more cost effective to cast them though if you wanted to use polyurethane. I've looked into it before but not seriously.

C|

[2drSE-i]

Unfortunately the money just wouldnt be there to produce them, in all honesty. If i ever came up with the cash, would you be able to fab poly bushings or motor mounts if i provided new, oem grade stuff? This is nowhere in the near future, but just for curiosities sake.

[Ichiban]

Unfortunately the money just wouldnt be there to produce them, in all honesty. If i ever came up with the cash, would you be able to fab poly bushings or motor mounts if i provided new, oem grade stuff? This is nowhere in the near future, but just for curiosities sake.

I've thought about this myself, and unfortunately, a lot of these products are somehow bonded to metal backers/sleeves etc. The actual machining of the parts is simple, however the bonding requires dedicated manufacturing techniques (such as pouring the insulator around the sleeve or on the backer) that only major manufacturers have the equipment to carry out. If that makes any sense.