RE: 1/4-20 thread?

From: will pattison (
Date: Wed Mar 24 1999 - 21:03:10 EET

trueform is quite brittle, and also does not machine well. if it's an
investment casting application, my suggestion has always been to put the
pilot in the pattern, then drill and tap the metal part, or leave an
oversize blank that can be turned and run thru a die later.


-----Original Message-----
From: Tom Richards
Sent: Wednesday, March 24, 1999 2:54 PM
Subject: RE: 1/4-20 thread?

Thank you for the feedback. Can you machine these threads in Trueform?

At 09:50 AM 3/24/99 -0600, you wrote:
>polycarb does not machine very well. i suppose i should have been more
>specific and stated that "sls nylon materials machine very well". i never
>even think of poly anymore because trueform and nylons have taken it's
>-----Original Message-----
>From: Tom Richards
>Sent: Wednesday, March 24, 1999 12:33 PM
>Subject: RE: 1/4-20 thread?
>Good idea! Which sls material are you machining? Carbonate?
>At 08:32 AM 3/24/99 -0600, you wrote:
>>i have never actually built any threads finer than about 3/4-16, but i am
>>speaking from several years experience as a dtm applications engineer,
>>more recently as a user of sanders, sla, and sls. given that the nominal
>>laser beam diameter in the sls process is 0.010"-0.020" (depending on
>>process parameters), and that the melt zone it creates will be similar in
>>magnitude, you quickly run into resolution problems with features like a
>>1/4-20 thread. the beauty of sls, though, is that it machines so well.
>> so, save the hassle, not to mention the cad time to create the thread in
>>the first place, and just drill and tap that sucker.
>>remember, the key to rp success is first understanding your fundamental
>>prototyping requirements, then picking the right tool for the job...
>>-----Original Message-----
>>From: Doug Bucci
>>Sent: Tuesday, March 23, 1999 9:57 PM
>>To:; 'Ray Brandes'
>>Subject: Re: 1/4-20 thread?
>>In response to you & Ray Brandes, I want to build both the male & female
>>threads in my jewelry
>>that will eliminate my need for commercial hardware & fasteners.
>>I am also interested in why you are dissatisfied with the your result of
>>building threads in SLS?
>>Thanks Again-
>>Douglas Bucci
>>PS-I would like to thank everyone for their responses.
>>My MFA exhibition:
>>-----Original Message-----
>>From: will pattison <>
>>To: 'Ray Brandes' <>; Doug Bucci
>>Cc: <>
>>Date: Tuesday, March 23, 1999 12:41 PM
>>Subject: RE: 1/4-20 thread?
>>>i doubt you'll be satisfied with the result making this thread directly.
>>> other than with sanders and maybe actua, you will have a hard time
>>>creating this thread in any rp machine.
>>>you didn't say if it was male or female, but either way, i would
>>>a secondary process. if it's female, model in a pilot hole, then drill
>>>tap post-build. sls nylon materials machine very well, so you should
>>>no problem.
>>>will pattison
>>>product development engineer
>>>4d design
>>>-----Original Message-----
>>>From: Ray Brandes
>>>Sent: Tuesday, March 23, 1999 9:49 AM
>>>To: Doug Bucci
>>>Subject: Re: 1/4-20 thread?
>>>I assume it is a 60deg V thread, but is it male or female? What class?
>>>Make the male body .25" diameter to the theoretical sharp point then
>>>remove .001 to .002 from the diameter.
>>>Make the female the same .25" to the theoretical sharp but add .001 to
>>>.002 to this.
>>>Does it have to fit an existing part? Can you make it heavy and then run
>>>a tap or die on it?
>>>Doug Bucci wrote:
>>>> Hello, I need to create a 1/4-20 thread in SLS can anyone provide me
>>>> with the minimum tolerances for creating this? Thank you,Douglas Bucci
>>> << File: ATT00002.html >>
>>For more information about the rp-ml, see

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