# Delrin Cross Slide Nut



## ddickey (Feb 28, 2017)

Anyone make a nut with Delrin? Thinking about trying this. I can't keep my cross slide lead screw and nut tight. Thinking it might be quite worn.


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## tincture500 (Feb 28, 2017)

Sounds like a idea that may work. Maybe the graphite filled stuff. Let us know how it turns out


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## tweinke (Feb 28, 2017)

Google eva nut and I'm sure you will suffer from information overload! Thinking of trying that for my 3in1 on the leadscrew.


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## Jimsehr (Feb 28, 2017)

Don't leave a space in evanut. I think it comes from a post by Evan Williams from Canada.
Jimsehr


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## didtas (Mar 1, 2017)

I   made    a couple   out   of   mazak   years   ago   ,  worked    good   .

Daniel.


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## 12bolts (Mar 1, 2017)

Not sure an evanut is ideal on a lathe cross slide unless you relieve the threads considerably. What do you mean by keeping the lead screw and nut tight?

Cheers Phil


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## ddickey (Mar 1, 2017)

I make an adjustment to take out most of the backlash, after a few trips back and forth the cap screws that hold the cross slide nut have loosened up. It is annoying. I read an article about making a nut out of Delrin, this guy also made a new screw as well.


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## 12bolts (Mar 1, 2017)

Lathes are not generally "adjustable" for backlash. You can allow/account for backlash by winding your feed past "a" point and then going back the other way. A good machinist would  always wind back on the cross slide then go back in to "zero"
My" badly" worn hercus needs a new leadscrew, however I can deal with + 0.050" backlash just by winding the dial further.

Cheers Phil


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## ddickey (Mar 1, 2017)

Depending on how you're turning yes, that is what I do.


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## coherent (Mar 1, 2017)

In the very first small home built CNC router I made I used acme threaded rod and blocks of delrin (which I threaded) for the nuts and bearing mounts they worked surprisingly well. They were easy to machine with basic tools and held up pretty well considering. If nothing else they would be cheap and easy to replace when they wear and the backlash becomes excessive. I've seen some very simple "double nuts"  which were made with two blocks with a spring compressed between them on the screw. The tension of the spring pushing the nuts apart reduce play/backlash even more.


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## 4GSR (Mar 1, 2017)

didtas said:


> I   made    a couple   out   of   mazak   years   ago   ,  worked    good   .
> 
> Daniel.


Hun!!

What the heck is "mazak"?  Do you mean "Zamak"?

Ken


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## RJSakowski (Mar 1, 2017)

coherent said:


> In the very first small home built CNC router I made I used acme threaded rod and blocks of delrin (which I threaded) for the nuts and bearing mounts they worked surprisingly well. They were easy to machine with basic tools and held up pretty well considering. If nothing else they would be cheap and easy to replace when they wear and the backlash becomes excessive. I've seen some very simple "double nuts"  which were made with two blocks with a spring compressed between them on the screw. The tension of the spring pushing the nuts apart reduce play/backlash even more.


I did the double nut trick on my old Atlas/Craftsman.  I used a previously replaced lead screw nut which floats on the lead screw.  The channel in the cross feed saddle prevents it from rotating.  It reduced the usable cross feed travel but reduced backlash to a thou or two.

One concern when using such a system is although backlash is effectively removed, a lead screw does not wear evenly along its entire length.  On a properly cut screw, the leading edges of the threads are a fixed, consistent distance from thread to thread.  As the thread wears in the heavily used region, that leading edge will move back several thousandths.  While the effect won't be that great over one or two turns, if you zero your dial and then move some distance, your dial reading may not be accurate.  Additionally, depending upon whether you are moving intoi or out of a worn region, the error can go either way.

The are two workarounds to this problem.  The first is to stop short of your intended position and make a cut and remeasure.   This is good practice anyway.  The second is to install a DRO.  The DRO records actual position so any wear is removed from the equation.


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## didtas (Mar 1, 2017)

Mazak     is    a zinc     alloy.   i    have used   it   heaps   of   times   for   a quick   fix.

car   door   handles  normally    use   mazak  alloy. Easy   to   melt    and     cast ,

  maybe   called    another   name   in    the   USA.


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## coherent (Mar 1, 2017)

"RJSakowski, said:   The second is to install a DRO.  The DRO records actual position so any wear is removed from the equation.

I suppose in my case since it was on a CNC machine it had a DRO in a sense. I just checked it every now and then and entered the backlash compensation in the driver software. Made new ones if it got too excessive but the delrin wears pretty well considering and it's low friction helps. I've also heard of using other types of polys with lower friction properties, but some of them can get pricey and it seems using delrin is generally done to keep machining easy and cost low.


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## 12bolts (Mar 1, 2017)

You shouldnt be just relying on a DRO for tool placement. If you fail to remove the backlash from your feed then the tool can move inadvertantly when it contacts the work.
It is good work practice to wind out, (or in) past any backlash and then reverse direction so the tool contacts the work in such a way the pressure is against the direction of feed.

Cheers Phil


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## 4GSR (Mar 1, 2017)

didtas said:


> Mazak     is    a zinc     alloy.   i    have used   it   heaps   of   times   for   a quick   fix.
> 
> car   door   handles  normally    use   mazak  alloy. Easy   to   melt    and     cast ,
> 
> maybe   called    another   name   in    the   USA.



Yeah, here that is called Zamak aka "pot metal".  Mazak here, is a machine tool corporation.


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## RJSakowski (Mar 1, 2017)

didtas said:


> Mazak     is    a zinc     alloy.   i    have used   it   heaps   of   times   for   a quick   fix.
> 
> car   door   handles  normally    use   mazak  alloy. Easy   to   melt    and     cast ,
> 
> maybe   called    another   name   in    the   USA.


It sounds like what we call Zamak
https://en.wikipedia.org/wiki/Zamak


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## Glenn Brooks (Mar 1, 2017)

I've read a couple of oldish threads on other forums where people have successfully used 
Delrin for both feedscrew nuts and gears.  Apparently it wears very well and has a long life.

Also, Replacement bronze feed screw nuts, even the screws themselves are readily available from Latheman, Miller Machine and Fabrication, several eBay vendors .  Current pricing for bronze nuts is $55 to $65 or thereabouts. Seems like a reasonable cost for new replacement parts.

Glenn


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## ddickey (Mar 1, 2017)

Jimsehr said:


> Don't leave a space in evanut. I think it comes from a post by Evan Williams from Canada.
> Jimsehr


http://bbs.homeshopmachinist.net/threads/43645-Making-Acetal-leadscrew-nuts-the-easy-way


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## willthedancer (Mar 2, 2017)

I would not use plastic. It adds another layer of potential tool pressure deflection. Bronze.

Sent from my Moto G Play using Tapatalk


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## 4GSR (Mar 3, 2017)

Plastics like Delrin work extremely well for lead screw nuts in applications where the atmospheric conditions are clean, free of crud, dust, etc.  They have to be run against a lead screw that has a ground and polished thread.  They can be run dry or lubricated with mineral oils or hydraulic oils or PTF base silicone grease.  This is why you see them used in the food industry with the proper food grade lubricants.  As for putting a Delrin nut on a lathe, its a toss up which way to go on this.  If your lead screw can be kept cleaned and lubricated and not heavily used, it will probably be fine.  This is only good if your lead screw is in good shape and not worn.  You practically have to use a new screw with polished thread flanks to get good life from a Delrin nut.  Delrin can only handle about half the load of a bronze nut, so no heavy feeding!  Most of us don't have to worry about this in our H-M environments.  I would say there is a size limitation on how big of a lathe to try this on. In my opinion, don't try on anything bigger than a 12" or 14" lathe.  Ken


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## 12bolts (Mar 3, 2017)

Delrin is used extensively in small engines, as, for 1, camshaft lobes, (in a well lubricated enviroment), and could be used in manual mill tables as a feed nut. However I question its application in, "a hobby machinist" application on a lathe.

Cheers Phil


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## Jimsehr (Mar 3, 2017)

Just to try it I got a cutting board from Walmart and cut two pieces and put them in vise and drilled a hole too the miner size of a 3/8 threaded shaft. Then I put in bench vise and heated shaft and formed the thread around the shaft. It took about half hour to make the whole thing. It seemed to work good but the thread was tight. 
I think it would get looser with use. And the stock was cheap about 2 bucks. Fun to try.
Jimsehr


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## Round in circles (Mar 4, 2017)

willthedancer said:


> I would not use plastic. It adds another layer of potential tool pressure deflection. Bronze.
> 
> Sent from my Moto G Play using Tapatalk



I've live in Great Britain & have been following a UK engineering forum for a long while .

 We have lots of precision engineering machinists who have day jobs playing with lathes & CNC machinery .  Their threads about Delrin for bearings & guide nuts that used to be brass or phosphor bronze are numerous .
The latest commercial & some hobby lathes & CNC machines apparently use all manner of Delrin  type plastics for nuts , bearings , some machine threads & flat or grooved locating low friction surfaces as it keeps its tightness due to being almost self lubricating at low speeds  & temps below 150 oC or so . It can also allow a little bit of metal dust /swarf to embed in the plastic with out much problem to the machine .  

 From another site I use ( All about circuits )  there are  also weekly presentations of the very latest innovations & advances that have been revealed to the world plus some great insights as to where things are heading . 

As the parts can be easily & very cheaply injection moulded or printed on a 3D printer to within a few microns almost any where in the world  remote from the CNC draughtman / designers ,  watch out for zillions of traditionally made metal parts including those above changing over to Delrin type plastics etc .  

 New plastics will soon be made commercially  from home grown bio materials instead of oil from the Middle East ..... I guess that will hasten the changes tremendously within a couple of years .


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## Allan (Mar 4, 2017)

My old Tida lathe has a horrendous amount of backlash in the cross slide screw. I can grab it and slop it forth and back. It makes turning risky because sometimes the rake angle pulls it into the cut and makes it hard to hold a diameter. Facing cuts end up a weird series of circles instead of a smooth face. It is not worn just poorly made. I have seen the Evanut and plan to put one on my machine. 

From what I've read there are some pretty substantial machine tools that use acetal nuts. From what I've seen of the material it is plenty strong. My attempts have not been all that successful. But I'll keep at it. Any results will be posted. If I ever get the time to get back to it.


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## ddickey (Mar 4, 2017)

Would I need to make a  new lead screw or just mold the nut onto my current one?


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## 4GSR (Mar 4, 2017)

Round in circles said:


> ............snip...............
> New plastics will soon be made commercially  from home grown bio materials instead of oil from the Middle East ..... I guess that will hasten the changes tremendously within a couple of years .


I have a chunk of thermoset plastic here in my garage that I watched being mixed from liquids made from corn, poured into a large coffee cup, and in about 1 hour it was harden solid ready to machine.  Of course, the chemical reaction created so much heat, took about a day for it to cool down to handle it.  The tensile strength of the material is just as equivalent or better that most thermoset plastics out there.  And there is no petroleum products used in the process.  Right now, it's only available in 55 gallon drums for commercial use for now.  Ken


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## Jimsehr (Mar 4, 2017)

ddickey it"s so easy to try I would just make nut and try it on your old lead screw.
If you do make it read the whole evenut post . A hell of a lot of people have tried it and are happy. 
jimsehr


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## 12bolts (Mar 4, 2017)

ddickey said:


> Would I need to make a  new lead screw or just mold the nut onto my current one?


Use the least worn part of your lead screw to make it

Cheers Phil


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## Allan (Mar 5, 2017)

Dickey, I bought a length of left hand threaded rod from Enco when the were till around. MSC and others probably still have it. What I did wash cut a "gash in the rod to help cut clearance on the nut. The one trial I made came out pretty tight. That way I have no fear of damaging the original lead screw.

As you can see in the second picture the nut did not stay entered. My plan on the second try will be to use a one piece nut that is slit on only one side.


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## Round in circles (Mar 5, 2017)

ddickey said:


> Would I need to make a  new lead screw or just mold the nut onto my current one?


  There are some You tube clips showing how a guy heats the screw to the plastic soft melt temp  & then uses a shaped heated split form to to clamp in to two halves  ..one either side of the rod & squash them on to it .
I think he had three cheap digital thermometers  onn the pieces to ensure he got his heating temps just right .
He managed to thermo form a a reasonable sized block of Delrin & then transfer it to his mill to get a true copy of the dimension

 . I can see that that could also be done on a lathe with a four jaw chuck & a bit of ingenuity b
 There can be the problem of it being a tad too tight ... I suggested to some guys thinking of copying it that perhaps they could used one of the aerosol sprays of stove coating to add a clearance coating to the thread . Then using a bar cutting tool & carefully ground cutter tip to clean out the paint using the lathe to give the acme thread requirements of speed & travel rate  .
 Once the thread is thermoformed the rest of the " Blob of plastic"  can be shaped  up  drilled & tapped with ease to get it close to the original shape .

 One word of warning keep it as thick /meaty as you can , but not so meaty that it catches up on things & prevents you getting the normal range of movements on your lathe.

Try looking for  " Delrin Hot thread forming " or  " Thermo forming threads in Delrin "  on the You Tube index list  or similar .

I'll see if I can find some of the ones I viewed as well..... a few minutes later ...
youtube.com/watch?v=rBIf_d_pAhQ
 This was one of the early un heated methods . he's used tube

 The heated version I saw was using angle iron to get th sides of the outer faces reasonably square .

youtube.com/watch?v=EVW7Q469RnA

 Similar to this one but the rod is gently & evenly heated to the ideal softening temp at both ends with a gas torch , so are the two angle iron clamping lengths   .
The angle iron clamp is clamped up in a 6 inch bench vice


This one may also be helpful for it shows where a source of excessive back lash can also be found on the cross slide shaft nut  . .
youtube.com/watch?v=NqF_ETWvBCA


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## 4GSR (Mar 5, 2017)

As much time and expense put into trying to heat and form a plastic around a thread, I can single point a thread on a piece of Delrin quicker and cheaper.


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## intjonmiller (Mar 5, 2017)

Delrin is not polycarbonate or polyethylene or other basic plastics. It is used in many high-demand industrial applications. Pretty amazing stuff actually.


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## jocat54 (Mar 5, 2017)

I made one for 7/16 x 10 acme (southbend 9A cross slide) and had extra length of acme rod, so knurled the end of the rod and threaded the delrin nut on a few times and cleaned the threads up nicely so it was a smooth fit.


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## intjonmiller (Mar 6, 2017)

DuPont recently produced a series of videos showing Delrin outperforming generic acetal at least in every test they chose to include. But they are also interesting just for seeing how the two materials perform in a variety of applications. Here is one example, and you can see the rest by clicking through to their channel:


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## intjonmiller (Mar 6, 2017)

4gsr said:


> As much time and expense put into trying to heat and form a plastic around a thread, I can single point a thread on a piece of Delrin quicker and cheaper.



The point of this method, though, is that it produces an *exact* fit. Practically zero backlash. That is an incredible feat with any method of thread cutting.


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## catceefer (Mar 6, 2017)

I had a similar problem on my small Flexispeed lathe, where the main nut had worn and had a lot of lash. I moulded Polymorph around the leadscrew and then cut it into a block. I then attached this block to the existing nut. It has removed all of the lash, is still light enough and smooth enough to use and, so far, is lasting well.

James.


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## 12bolts (Mar 6, 2017)

Jon,
I know you said "practically zero backlash" but you cannot also, have an "exact" fit on a thread. It will not work. And even if you have created your "practically zero backlash threaded nut", you still need to wind out past the backlash and back in again to avoid take up problems.
Granted Delrin is a great product. And I do have a Delrin evanut on my mill. But you cannot, (on a home scale), eliminate backlash and dodge basic machining practice. One of the 1st things we learned in machine shop was wind out, then wind back in to zero.

Cheers Phil


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## intjonmiller (Mar 6, 2017)

Allow me to rephrase: a Delrin nut molded to a leadscrew will get you as close to zero backlash as you will get by any method short of a ballscrew.


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## HMF (Mar 23, 2017)

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## Tozguy (Mar 23, 2017)

No matter the material or method used to make a lead screw nut, it cannot correct for poor quality or uneven wear in the lead screw itself that I know of. Getting the right feel from one end of travel to the other is an elusive goal and ultimately a personal choice.
Molding a polymer nut on the lead screw is an interesting approach that I hope to try eventually if the situation warrants. For now the metal split nut currently riding the lead screw is adjustable so backlash can be adjusted to my liking.


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## RJSakowski (Mar 24, 2017)

Turcite is a plastic which combines acetal and silicone and used on wear surfaces in many applications, including lathe and mill ways.  Delrin is a trade name for an acetal polymer. Delrin AF contains Teflon and is used for similar applications as Turcite

I have used both acetal and Delrin and can't honestly say that I noticed any difference in performance.  For the purposes described above, either should work.  They tend tend to have self lubricating properties which is why it is used for bearing surfaces.  Delrin has a yield strength of between 6.5 and  9.6 Kpsi or about 30 to 45% that of bearing bronze.  Delrin and acetal a common choices for gears.  When I built the reversing banjo for my 602, I used acetal gears. Given the contact surface for a lead screw nut, I would expect good to excellent performance under conditions normally seen in a small lathe.

I have done a bit of thermal machining of Delrin.  In one instance, we were looking at making a .009" hole in a 1" block.  I used a length of wire connected to a power supply to "cut through the plastic much like a weighted string on a block of ice.  The Delrin melted around the wire and the wire slowly moved to the center of the block with melted Delrin filling the path and freezing.  The result was a wire embedded in a solid block of Delrin.  When everything had cooled down I pulled the wire, leaving a .009" hole.

If using the above described method to form a lead screw, the Delrin will shrink as it solidifies which will result in an interference fit.  Typically, a clearance fit in a  screw /nut is obtained by modifying the basic pitch diameter.  With the Delrin thermoformed nut, it will also be changing the thread pitch.  This will amount to a preload which can be a good thing if it isn't so much as to prevent movement. 

One word of caution when heating Delrin.  It gives off some very obnoxious fumes if heated to  too high a temperature which attack the eyes and mucus membranes so do so in a well ventilated room


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## 4GSR (Mar 24, 2017)

R J,

An excellent write up for Delrin and comparison to Turcite.  And yes, it gives off some obnoxious fumes when machining the stuff, too!

Ken


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## Glenn Brooks (Mar 24, 2017)

ddickey said:


> Would I need to make a  new lead screw or just mold the nut onto my current one?


You will likely need a new lead screw also.  The screw and nut wear together and change geometry depending on which part of the screw gets used the most. You can measure the thickness of the threads where it wears the most and compare to the ends to see if you have excessive wear.   I just replaced my cross feed screw and (bronze) nut on a SB Fourteen, and the new parts makes a world of difference.  Solid, predictable tool movement, much better finish, a great improvement.  Brian at Miller Fabrication and machine made it and delivered in a few days time.  My lead screw is fine, but pretty soon will do the same thing with the compound screw.

Glenn


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## Tozguy (Mar 24, 2017)

RJSakowski said:


> If using the above described method to form a lead screw, the Delrin will shrink as it solidifies which will result in an interference fit. Typically, a clearance fit in a screw /nut is obtained by modifying the basic pitch diameter. With the Delrin thermoformed nut, it will also be changing the thread pitch. This will amount to a preload which can be a good thing if it isn't so much as to prevent movement.



A good point. In my case I prefer to have the least amount of drag between lead screw and nut even at the expense of a bit of clearance. Bear in mind that another source of backlash is the lead screw to carriage connection so we have to live with backlash in the system anyways you look at it.

 What is important to me is that I can feel only the drag in the dovetails when setting the gibs and when operating from then on. The technique that Phil mentioned in post 38 is a reflex for me.


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## RJSakowski (Mar 24, 2017)

Add to the backlash equation, the clearance in the lead screw thrust bearing  and "lost motion" caused by flex of the "solid" parts when force is applied.  The latter, almost counter intuitively, increases as you tighten things up.

Regarding the thermoformed nut,  A makeshift tap can be made from a section of lead screw to cut clearance in the nut.  Simply grind a cutting edge in the fashion of a tap in an old screw thread.  For cutting Delrin, it needn't be hardened but remember that Delrin likes a sharp edge.   If you don't have an old screw laying around one can be made fairly easily by single point threading.


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## ddickey (Mar 24, 2017)

Glenn Brooks said:


> You will likely need a new lead screw also.  The screw and nut wear together and change geometry depending on which part of the screw gets used the most. You can measure the thickness of the threads where it wears the most and compare to the ends to see if you have excessive wear.   I just replaced my cross feed screw and (bronze) nut on a SB Fourteen, and the new parts makes a world of difference.  Solid, predictable tool movement, much better finish, a great improvement.  Brian at Miller Fabrication and machine made it and delivered in a few days time.  My lead screw is fine, but pretty soon will do the same thing with the compound screw.
> 
> Glenn


Glenn,
You replaced just the nut?


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## ddickey (Mar 24, 2017)

I took my compound and cross slide apart a few days ago just to clean and inspect. I was not certain about taking the top part of, I guess it would be the carriage off. Anyway two things I noticed. when I put the cross slide gib back in it stuck out more than before. I really can't even get the wiper to fit properly. Also I didn't realize the small thrust bearings on the handle can also be a source of backlash. You can't tighten them down real hard or you won't be able to move the handle.


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## Glenn Brooks (Mar 24, 2017)

Ddicky,  no, sorry wasn't clear,  replaced both nut and cross slide screw. Both were worn, not badly, but caused a lot of erratic cutting action and very inconsistent and undependable depth of cut.  Rock solid now, thanks to Miller Fabrication and machine!

Also, re: your last post.  Look for swarf or chips that may have accidentally dropped into your ways or cross slide dovetail as a possible reason for not fitting back together as it should.  Generally when I have cleaned my equipment of of old oil and gunk things loosen up more, not less than before - due to increased clearance caused by removing old dried oil etc from the mating surfaces.  Once in awhile chips sneak into the cleaned area and get  snared by the fresh oil, obstructing the fit you expect.  

Also sometimes the wipers are not symmetrical. Try fitting them to opposite ends to see if the screw holes line up better.

Indeed the thrust bearings and gib work together, sort of, to control unwanted movement of the cross slide.  I found first, take slack out of the screw with the thrust bearing (use a dial indicator to reduce overall cross slide movement to as close to .000" as you can - however to binding on the wheel- back off a tiny amount to get the torque load on the bearing just right - finger smooth movement is the goal. Then tighten up the gib to stop side to side 'rocking' movement of the compound base on the apron. Then when it binds, slackmoff a nudge to get easy fluid one finger control of the cross slide.  It turns out to be a delicate adjustment on both parts....

BTW, Iam also replacing my gib and the rear thrust bearings on my SB Fourteen in hopes of having more control over the adjustments of the cross slide .

Cheers, it will all work out!

Glenn


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## Round in circles (Mar 24, 2017)

RJSakowski said:


> Turcite is a plastic which combines acetal and silicone and used on wear surfaces in many applications, including lathe and mill ways.  Delrin is a trade name for an acetal polymer. Delrin AF contains Teflon and is used for similar applications as Turcite
> 
> I have used both acetal and Delrin and can't honestly say that I noticed any difference in performance.  For the purposes described above, either should work.  They tend tend to have self lubricating properties which is why it is used for bearing surfaces.  Delrin has a yield strength of between 6.5 and  9.6 Kpsi or about 30 to 45% that of bearing bronze.  Delrin and acetal a common choices for gears.  When I built the reversing banjo for my 602, I used acetal gears. Given the contact surface for a lead screw nut, I would expect good to excellent performance under conditions normally seen in a small lathe.
> 
> ...



  Nice one RJ
Re :- The fumes , it also catches alight with a nigh on invisible flame & it sticks to your pinkies very well , even the tiniest burning splodge is agony ... guess how I found out ?

 In the earlier post I mentioned using cheap digital thermometers fixed to the bar  at the ends & a free one to check the middle to ensure you get an even quality melt .

If you heat the threaded bar to the melt point ( do a test on some scrap & scrap thread to find you thermoplastics melt point ) and use a square former (made from  two sections of angle iron ) you can make melt nuts or other shaped parts  for that matter of fact  .  I've been considering  making a smooth aluminium cylinder with an aluminiun piston at each end in which I've taken out enough metal to make a cast form  put in sufficent plastic ( by volume in water .... Eureka I've found it ) then use the heat method I've described & a vice to squeeze things up to produce repeatable parts Using my Dremel to grind /remove metal so as to get the forms I need in the soft aluminium piston faces.



Reading the post about turning a single point thread   , I've seen a set of quality Acme taps available at the cost of an arm & a leg too .
Would either  way work well on a 3/8 internal acme screw thread ?

I can see it would be difficult for me to turn one up with my limited skills in such things , especially getting the tool cutting angles correct for an Acme thread .
However I've learnt  to turn up a very accurate rectangular square block in the four jaw chuck out of all sorts irregular shaped rubbish /scrap . Perhaps putting a thermoformed nut on an acme thread & then turning it to a round rod between centers should allow me to use the cross slide to put a decent mounting flat along the cylindrical face & have it reasonably accurate when aligning / fitting things up .

 Another thing might be buying a fairly thin walled acme phosphor bronze sleeve , knurl it a bit then thermo-form / embed it in  the bigger part of the assembly ,

Ooooh ,  I'm spoilt for options & have so little time to play at doing them . Oh for a decent precision mill, lots of attachments  & the space to put it  .


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## RJSakowski (Mar 24, 2017)

Hey David,
It sound like a plan re molding the nut.  According to Matweb, Delrin has a melt temperature of about 200ºC and experiences a 2% shrinkage.  

Looking at my Atlas 6x18, I could use the cross slide base as a mold.  I would need to bushings to form the end caps.  The existing nut could be used as one.  I actually have a spare, having replaced my leadscrew and nut several decades ago so I would have both end caps.  I guess that I would preheat the leadscrew and cross slide base. Matweb gave a mold temperature of about 80ºC but that would be for injection molding where the injection time is measured in millisec. and they want fairly rapid freezing of the melt.  I think that I would look for something like 100ºC or more.  I expect that other lathes could be done in a similar fashion.

Anyway, good luck with the project and let us know how it works out.


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## Round in circles (Mar 25, 2017)

If I stay healthy enough & don't forget to   .
I do indeed hope to make a new heat formed nut or three ...not particularly because I need to , but primarily because I want to , as I have many many 30 to 40 mm thick x 180 mm dia off cut rounds of Delrin .
 I'd like to become good at making them in many different thread forms as well as doing  the simple work bench pressure forming /  casting I've mentioned .  Learning to do them & the castings accurately & cheaply may well see me with a nice little retirement fund $ earner $ that the larger companies don't want to bother with  .


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