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View Full Version : How do I mount my delrin nut? Inexpensively.



arthernan
09-23-2010, 03:25 PM
Hello anyone!!!

I read enougth on nuts to convince myself of this. The most cost-effective way for me to minimize back-slash on my CNC Router proyect is to make my own acme tap out of a piece of acme screw, and make delrin nuts out of delrin rod.

A foot of rod will cost me about $20 with shipping.

And now that I have come to this conclusion, the issue at hand is how do I mount it?? Well I thougth I could just get a 2"x2"x2" piece of solid Delrin until I saw the prices. $200+!!! :nono: So that, went out the window. I thougth maybe a pillow bearing, but how would I keep the nut from spining??. :confused:

I have checked the price of a solid piece of aluminum to hold the nut, a 2" thick to hold a nut of the same length, of course I would need to make the hole for the nut and screws to attach it. The aluminum is about $27 a foot, no ship. But an angle with a .25" wall is about $7 a foot. Then I thougth to avoid using wood, I could buy a flanged bearing, screw it to an angle and tap the bearing to put a mini screw in to hold the nut.

Am I making any sense? :confused: I did search for an answer here but I could not find it.

SORCHEROR
09-23-2010, 03:44 PM
i sell plastic acme nuts that have a mounting flange on the with two clearance holes,which are slotted for alignment,i usually recomend two for each axis with a spring between for backlash,i sell the nuts for $7 each,you cant find them cheaper anywhere
that ive seen,any if interested i will gladley post a pic or two,these are 1/2-10 single start,i can also provide 5/8

leggazoid
09-23-2010, 07:36 PM
http://www.dumpstercnc.com/

Maybe this is useful info?

arthernan
09-24-2010, 01:31 AM
OK, I looked at the dumpstercnc link and I may upgrade to these later. $20 dollars of delrin is a close to a fourth of the $78 for 3 dumpsternuts. I don't want to sound cheap, but my list of materials is close to $500.:violin:

My problem remains how to mount them inexpensively. I may do a lot of research and remember my physics classes. But I am still a newbie. Any help will be greatly appreciated!(group)

SORCHEROR your offer does sound appealing. Could you please post a pic?

sonex128
09-24-2010, 02:07 AM
Yes please post pics. I am trying to figure this out now. Can't quite afford the dumpstercnc ones right now.

Brian

MrWild
09-24-2010, 02:22 AM
why are you asking this question? You need a lathe in order to do a nut properly, and a tap of some sort which can be a chunk of the Acme rod you will be using. If you are planning on using all thread as your lead screw... Well you could use glue. No I jest. But in order to do a good job on the nuts, drill them on center, etc. you should use a lathe. Once you are using a lathe, it is a simple matter to thread the outer diameter (OD) of one end and then thread the nit into a plate. All this is so much work you'd be better off buying the cheap $7 nuts.

I'm wondering why you paid so much for your plastic. I bought a box of 2.5"dia. off cuts and paid $25 with shipping for so much Delrin plastic it will last me years. Sure it's a gay pink color, but I call my machine a she so it works out. On a cheap cheap cheap all thread lead screw machine, your mounting plates could be MDFB that have the mating threads hardened with a thin super glue (cyano-acrilate). But then you have the added costs of the glue.

My advice is toss the chunk of plastic in a box and label the box, failed attempts at being cheap. Buy the $7 nuts and be done with the head ache.

doorknob
09-24-2010, 08:05 AM
There is a thread on a different forum that may be relevant to this one - see http://bbs.homeshopmachinist.net/showthread.php?t=43645 "Making Acetal leadscrew nuts the easy way" - it describes and illustrates a method for using acetal copolymer or Delrin, an acme leadscrew, and a heat gun to create acme nuts (and half nuts) that closely conform to the leadscrew threads. A lathe is required to bore an ID into the acetal material ahead of molding the threads, as well as to turn down the OD after making the nuts. There is some discussion of mounting techniques in that thread.

Dean448
09-25-2010, 08:25 PM
I'm using a 1/2" 10 5 start acme lead screw and also asked if there isn't a cheaper way to get anti-backlash nuts. What I came up with and its been working flawlessly for ten months is two part pourable plastic. The plastic is poured while everything is mounted on the machine. Advantages are no machinging, perfect match to the lead screw, perfect alignment, I have not been able to preceive any backlash, very strong, could also pour and cut resulting in a split nut design, Doesn't ingest debris because there is clearance between the nut and screw. The only disadvantages (which might also be present in a delrin system) repeated motion of a heavy Z axis tends to heat the surface up and I occationally put a lubricant on the lead screw to eliminate a dry squeal sound.

roy_okc
09-27-2010, 07:24 PM
I'm using a 1/2" 10 5 start acme lead screw and also asked if there isn't a cheaper way to get anti-backlash nuts. What I came up with and its been working flawlessly for ten months is two part pourable plastic.

Dean,

What brand is this pourable plastic? Do you have a link?

Thanks,
Roy

trevis1st
09-27-2010, 07:28 PM
You might try polytek.com.

Dean448
09-27-2010, 10:25 PM
www.alumilite.com (http://www.alumilite.com)

I used white for the x-y axis and tried Vac 50 for the z axis to draw some heat out. Either would work for all. If you give this a try I'd use a heat gun to warm the screw then spray on a light coat of silicon. The spray acts as a release and the heat allows it to cure without bubbles forming. If it doesn't turn out for some reason then just drill it out and pour it again. For your information my nuts are all poured to 1" long based on a 2:1 length to diameter. I expected to see some wear by now and have to pour it again but the nuts are all still tight.

Dean

ger21
09-27-2010, 11:06 PM
Here's how I did mine, but I turned it on a wood lathe.
http://www.cnczone.com/forums/showpost.php?p=127767&postcount=117

FandZ
09-28-2010, 08:41 PM
www.alumilite.com (http://www.alumilite.com)

I used white for the x-y axis and tried Vac 50 for the z axis to draw some heat out. Either would work for all. If you give this a try I'd use a heat gun to warm the screw then spray on a light coat of silicon. The spray acts as a release and the heat allows it to cure without bubbles forming. If it doesn't turn out for some reason then just drill it out and pour it again. For your information my nuts are all poured to 1" long based on a 2:1 length to diameter. I expected to see some wear by now and have to pour it again but the nuts are all still tight.

Dean

Do you have pictures posted of your setup? I'm interested n seeing how it came out.

gmfoster
09-29-2010, 03:31 PM
i sell plastic acme nuts that have a mounting flange on the with two clearance holes,which are slotted for alignment,i usually recomend two for each axis with a spring between for backlash,i sell the nuts for $7 each,you cant find them cheaper anywhere
that ive seen,any if interested i will gladley post a pic or two,these are 1/2-10 single start,i can also provide 5/8

Please post your pictures and information on purchasing..
Thanks

Dean448
09-29-2010, 08:38 PM
The attached two images are from my X and Y axis. This is a welded steel gantry style machine with two Y axis lead screws each using a single nut, shown with the mounting strap on the outside. The X axis gantry has two nuts on the same lead screw. I was looking for the same nut cross section for each axis so I doubled up on the X axis. Each nut design is identical, 1 1/4" support strap welded to a right angle shelf that holds the 1" square tube that holds the plastic. The 1" square tube has two ~5/8" holes drilled in it for lead screw clearance. Seal gaps with modeling clay during the pour. The nut assy is mounted with cap screws to a box frame holding V bearings. As you can see the nuts are very rigidly held. I left the machine as is so you can see the wood buildup where the lead screw enters the nut, but with no clearance very little debris should penetrate the nut. Also any dings to the diameter of the lead screw won't hurt the accuracy that is maintained to the sides of the square acme threads.

Dean

quazga
09-29-2010, 10:28 PM
You might try polytek.com.

In regards to Polytek I would go to BITY to get Polytek's products as you'll find them a little cheaper there. You can find the pertinent page here: http://www.shop.brickintheyard.com/Resin-Liquid-Plastic_c8.htm

However, do stop by Polytek to get a copy of their catalog which has excellent mold making info. You can find it here: http://www.polytek.com/catalog/catalog.pdf

I wonder if you couldn't add a small percentage of Teflon powder and come up with something even better than Delrin! :D

FandZ
09-30-2010, 08:32 PM
The attached two images are from my X and Y axis. This is a welded steel gantry style machine with two Y axis lead screws each using a single nut, shown with the mounting strap on the outside. The X axis gantry has two nuts on the same lead screw. I was looking for the same nut cross section for each axis so I doubled up on the X axis. Each nut design is identical, 1 1/4" support strap welded to a right angle shelf that holds the 1" square tube that holds the plastic. The 1" square tube has two ~5/8" holes drilled in it for lead screw clearance. Seal gaps with modeling clay during the pour. The nut assy is mounted with cap screws to a box frame holding V bearings. As you can see the nuts are very rigidly held. I left the machine as is so you can see the wood buildup where the lead screw enters the nut, but with no clearance very little debris should penetrate the nut. Also any dings to the diameter of the lead screw won't hurt the accuracy that is maintained to the sides of the square acme threads.

Dean

Thanks for the pictures. Pretty cool indeed.

eaglezsoar
10-01-2010, 06:58 AM
You might try polytek.com.

Which product would you recommend from this Company for creating
the nuts? Thanks in advance.

SORCHEROR
10-16-2010, 11:37 AM
sorry for the delay,ive been swamped,here is the ebay link
1/2-10 acme delrin leadscrew nut - eBay (item 130444404209 end time Nov-15-10 00:00:29 PST) (http://cgi.ebay.com/1-2-10-acme-delrin-leadscrew-nut-/130444404209?pt=LH_DefaultDomain_0&hash=item1e5f17a5f1)
im selling them for $5 each if you buy 3,$15 for a set of 3,if you want to spring load two per axis for zero backlash you will need to buy 2 sets for $30,shipping is $8,if you buy 2 sets shipping will still be the same,these are our economy nuts,in a month or less we will have a single zero backlash nut avaiable,no more need for the spring and second nut
wouldnt mind some feedback on what you guys think,
thanks,steve

FandZ
10-16-2010, 01:39 PM
sorry for the delay,ive been swamped,here is the ebay link
1/2-10 acme delrin leadscrew nut - eBay (item 130444404209 end time Nov-15-10 00:00:29 PST) (http://cgi.ebay.com/1-2-10-acme-delrin-leadscrew-nut-/130444404209?pt=LH_DefaultDomain_0&hash=item1e5f17a5f1)
im selling them for $5 each if you buy 3,$15 for a set of 3,if you want to spring load two per axis for zero backlash you will need to buy 2 sets for $30,shipping is $8,if you buy 2 sets shipping will still be the same,these are our economy nuts,in a month or less we will have a single zero backlash nut avaiable,no more need for the spring and second nut
wouldnt mind some feedback on what you guys think,
thanks,steve

Is that pictured with a 1/2 lead screw? Also, what are the dimensions for the nuts and mounting hole lengths?

SORCHEROR
10-16-2010, 02:17 PM
yes,thats the 1/2 screw shown,the nuts are 1.0 inch wide,2.750 inches long
center to center of the mount slots is 2.00 inches,i originally designed it for one nut
than used a second nut and spring for the backlash,one nut locks down and the other floats with spring tension,in about a month i will have the new nuts out,the good thing is they will bolt right in place of the old one with no need for the spring and the second nut
they will be about $9,i hope,im trying to keep everything low price for people on a buget
about the same time i will have motor mount bearing blocks
thanks,steve

mlabruyere
10-16-2010, 02:57 PM
I just got a block of plastic (HDPE I think) for my small foam CNC (actually a buddy on another forum did this and I got it from him). This left me a nice big block to drill holesthrough to mount it to the carriage. I've got the machine torn down right now...It's not pretty but it works....

The milled and lathed ABN's y'all are showing here look store bought! Really nice work.

prcdslnc13
10-28-2010, 04:01 PM
to sort of vouch for SORCHEROR, I made an assembly almost exactly like this about 3 months ago for my tabletop router out of HDPE and 3/8-16 threaded rod (super cheap machine) and it works incredibly well. The one thing I did do differently is I added bolts on either side of the lead screw to help adjust tension more and to help keep the floating nut in place. Later I found out that the bolts are completely un-needed. Oops, haha. Anyway good design, much prettier then mine.