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gundog
08-09-2005, 10:10 PM
Does anyone have a connection to buy machinable plastic rods like delrin only cheaper? What are some cheaper alternatives to Delrin or Acetal. I will be making some rollers or shives for my new anchor holder design I need to get some 3.5" dia x 7" long material or multiples of that demention that I can cut to size and bore a .5" hole.
Mike

wierdscience
08-09-2005, 10:51 PM
I have in the past used a couple different companies,but they were either neck and neck with McMaster-Carr or more expensive,so I quit them and went with McMaster.

Michael Az
08-09-2005, 10:57 PM
There is always lots of Delrin at ebay in small quanities.
Michael

snowman
08-09-2005, 10:58 PM
hdpe (high density polyethylene) is probably cheapest that i can think of

wierdscience
08-09-2005, 11:10 PM
I have had good luck with these guys in the past-

http://www.piedmontplastics.com/

Just for refrence,here are the part numbers for McMaster-Car UHMW 8701K57 HDPE 8624K48 DELRIN 8512K35

Notice the compressive strengths,quite a bit of difference in the three.

winchman
08-10-2005, 07:37 AM
You might also try:
http://www.machinist-materials.com/default.htm

Roger

Swarf&Sparks
08-10-2005, 08:18 AM
I'll stand correcting here, but I think Delrin is a trade name for acetal-homopolymer. Made some sliding bushes for a small machine. Delrin was big $$$$, generic acetal a lot less spendy. I'm in West Oz and dealt with a company in Qld called small bearings (Or similar). They deal with, largely, a hobby/modeller market. Service was great, delivery quick.
Not suggesting you deal with em, just that the plastic is the same and has worn well.
Rgds, Lin

Evan
08-10-2005, 10:22 AM
Gundog,

Try pricing Nylatron. It is moly filled structural nylon and is tough as nails. The moly filling gives it lubricant properties. I find the best way to bore it is with a spade bit. This gives plenty of chip clearance and doesn't bind or produce much heat. This part was drilled with a spade bit.

http://vts.bc.ca/pics/nylahole.jpg

gundog
08-10-2005, 11:49 AM
Thanks for all of the replies. I am trying to start a small business with my new product I have created. I am trying to put a cost together per unit to see if this will be worth taking on and Delrin which is a trade name from Dupont (I think) is the same as Acetal I found this out reading some info from machinist-materials. I will research the info from here to see what I can find out.
Mike

cuemaker
08-10-2005, 01:49 PM
You can go to these guys

http://www.atlasfibre.com/

My understanding is that they are the one of the largest producers of delrin plastic sheets and rods. The purchase the raw material for plastic from Dupont or who ever and then make it.

I dont know about minimun quantity etc.

Evan
08-10-2005, 02:06 PM
I did a price check on Delrin vs Nylatron and found Delrin at $94.90 per foot for 3.5" stock. Nylatron is $76.72 and will work just as well or better than the Delrin. Nylatron is recommended for sheaves and pulleys etc. Nylatron appears to be the least expensive alternative of the various suitable plastics.

JCHannum
08-10-2005, 02:12 PM
If the product is being used in the presence of water or moisture, nylon may not be the best choice, it will absorb moisture and change dimensionally. Delrin absorbs less, and acetal even less.

Evan
08-10-2005, 02:37 PM
Not much difference between Nylatron and Acetal in 24 hour immersion. Nylatron absorbs 0.3% and Acetal 0.2%. It does make a difference if it is fully immersed for a long period of time.

gundog
08-10-2005, 04:54 PM
What the devil are they making this roller out of?

http://img.photobucket.com/albums/v292/millnut/DSC02689.jpg

I am going to be making a similar unit this roller has an OD of 3.5" at the largest point and is 4" long. The whole unit only cost $80. My unit has a total of 3 rollers but two of them are only about an inch thick If I have to spend $76 a ft for just the roller material I won't make any money at this. I know they don't spend that much maybe the roller is made from another material. It seems to be a hard plastic of some sort but I don't know much about plastic. The units will get wet but not imersed in water. If they do get imersed while on the boat I don't think the roller will be the problem :~(

Evan
08-10-2005, 05:03 PM
I wouldn't be suprised if it is injection molded HDPE or even recycled mystery plastic. They probably buy at least a 1000 at once too.

You can't compete with a part like that by machining them from raw stock.

[This message has been edited by Evan (edited 08-10-2005).]

wierdscience
08-10-2005, 11:16 PM
Buy the roller,make the bracket.You could plunge it in one pass with a form tool,assuming enough lathe and hp,but the material cost is the kicker.Even LDPE at $12 a foot would be on the high end price wise.

A trip to a big marine supply might yield a source for the roller.