Homemade spindle liner questions

I want to make some "doughnuts" to go in my spindle to support long stock. I have read the various forum posts on the subject but have some questions.

I am going to make some delrin disks (or doughnuts) and will put an o-ring groove in the od and put a soft buna o-ring (from Mcmaster) on it so it fits snuggly in the spindle.

I was thinking I would need maybe 4 of these along a 36" bar. Is that enough or too many?

I was thinking they would be about 1" long. Is that a good length or should I make them longer?

My spindle is 66.5mm(2.618") ID. I was going to get a 2-5/8" OD(2.637" actual) o-ring and make the disk diameter 2.52" DIA. Is it ok to have the disk nearly .1" undersized and have the o-ring take up the difference? I want to be able to get them in/out easily enough.

How close to the stock diameter does the ID of my liner disks need to be? As one example, if I want to use 0.5" hex stock which from point-to-point is 0.577" OD, can I bore the liner disk to 0.625" or should I get it closer to .577?
-Tom

For my Haas with a 2.550" bore, I use Ø2.50" OD bushings made from leftover Ø2.75" PVC rod.
They are about 3" long, with an oring groove on each end. I went with about a 10% squeeze on both rings.
They run about 0.02-0.03" ID clearance on the bar. (if it doesn't start to whip, it never will)

The front, OD of the bushing has a large (1/2x45°) chamfer, to facilitate easy entry into the spindle bore.
The ID on the back of the bushing has about the same chamfer, to allow for easy bar loads.
For a 36" drawtube, we usually run 2-3 bushings.

I am not above buying Trusty-cook liners either.

I bought a liner then copied it for different sizes.

Basically it’s a tube with 3 donuts. They are about an inch wide. The o-ring is on the far end of the liner which is flanged to butt against the end of the draw tube.

There’s only .010/.015 clearance from donut OD to drawtube ID.

I don’t like your 3 donut idea because as your stock drops off each donut it’s going to whip inside the drawtube.

I don’t really have problems with stock being as much as 1/4” smaller than the spindle liner. Sometimes I just have to belt sand a big chamfer on the bar. Make sure the inside of your jaws are also chamfered.

I made a bunch of spindle liners like you're contemplating. I'll just say it was a big and long involved job. Just finding all the proper DOM at the steel yard took plenty.

My draw tube is 66mm so you'll have to take what I've got here and adapt to your situation. Looks like I made the spacers, 3 per tube and each about an inch wide at 65.5mm diameter. I used #228 Buna-N O-rings from McMaster. Measuring over the o-ring in the groove it's trying to tell me 66.5mm The groove diameter measures just under 60mm and is 3/16 wide. My programming says o-ring groove is 0.188 wide by 0.112 deep as a radius. (X incremental)

Not sure where you're getting this hex idea from but doesn't strike me as the way to go.

I suggest you make one complete and test the fit. I remember that my first attempt(s) were not correct. Not bad but not what I wanted. Remember you want some free space inside the tube. Don't recall exactly but in the 30-60 thou range. There's info on spindle liner websites that talk about it. Think it all depends on if you run a lot of hot rolled or cold drawn stuff.

I created a master fixed plate that bolts to the rear of the hydraulic actuator and the last of each of the tube flanges bolts to that. Honestly I'm not sure if you need it fixed or not. I'm using a bar feed so went that route. They do seem pretty secure on their own.

My woodworking friend made me the rack when it was all said and done. Good luck.



Ha-ha... looks like the OP got plenty in the span of 6 minutes. Guess everybody's made spindle liners.

If the liner will be used often, Trusty-Cook liners are great.

.625 ID will be fine for .577" stock.
For the O-ring, make sure it seats at least halfway in the groove so it doesn't slide off.
2.625 measured over the O-ring, so for a .125" O-ring ring a groove at X2.375
The disc size should 2.5"+ in this example.
Start there and see how it feels.

By the time your done making 2 or 3 pcs. though a liner would be half paid off.

Thanks for the responses! Shelling out $250+ for every size liner I need seems like a lot. I am not (currently) jobbing out the machine time so while $250 for one job may not be much, it is when there is no job :-) I will make one liner and see how it goes. Again, thanks for the replies. Very good information and has given me much to think about.
-Tom

These are made for Haas machines, but you have a lathe so you could turn down if too big!



Not sure where you got $250 price tag. Also, check Ebay, seen some on there.

I make the donuts. They work great, another idea I got here on PM. I use black delrin. Mostly because I find having a little black delrin around the shop is handy for other things too. Any plastic would work I guess. Like Doug925 I put a big O ring groove in the OD. The groove is mostly toward one end so most of the bushing is in the bore before the o ring grabs. I just bought a bag of big fat o-rings from McMaster. Can't remember all the details but it's not all that important. Also like Doug925 a big chamfer on one end. They take just a little time to bang out on the manual lathe. I use 2-3 of them in the spindle. No problems I have seen with whipping etc.

Oh, and the other thing I do is to notch the od o-rings before installing them on the donut. When using a collet chuck sometimes it fills up with coolant between the chuck and the first donut- particularly my 5c chuck. The notches allow the coolant to leak back out to the back of the spindle and into the drain.

Mike1974 said:

These are made for Haas machines, but you have a lathe so you could turn down if too big!
View attachment 294823

Not sure where you got $250 price tag. Also, check Ebay, seen some on there.

Click to expand...

They aren't big enough. I need a 66.5mm OD, these are 51mm. My lathe won't let me turn them up

$250 is Trusty Cook's price for the liners I'd need.

Donuts suck, they move around when you put your stock in and also from vibration. not to mention they are a pain in the ass to get out.
if you want somethign cheap and fast and effective.
grab some 1/2 3/4" and 1" etc etc conduant just cheap crap.
turn a alum slug for the back end then turn one 8-10 inches away from front end.
bore them a few thou smaller than the od of the conduant. put orings on the outside of the slugs .

then grab conduit and press or hammer it into the slugs and walla you have a draw bar.
one thing you can do it take a center punch and punch a bunch of holes into the inside of the conduit then wipe epoxy and press in. I never have as the press holds for years and years. still have some for 15 years ago working just fine. they run true and can run 6k rpms no problem all day long.
Take 2 hours to make if that and you probably have everythign in your shop.

Delw said:

they move around when you put your stock in and also from vibration. not to mention they are a pain in the ass to get out.

Click to expand...

Mine never moved. In fact they stick in there pretty well. To remove I have a piece of wood that I put in the spindle end while changing collets, pads or whatever, and pop them out the back side. No issues there.

Delw said:

and walla you have a draw bar.

Click to expand...

That's a new one

I've made several and they are a pain in the ass. Now I just buy them from Trusty Cook. The price is based on drawtube ID, I think mine were more like $175/ea... not cheap but if you buy one a month, you won't even notice it and within a year you'll have pretty much everything you need. You can also use a cheap piece of tubing if necessary to adapt a bigger liner to smaller stock... not ideal but if it's a one-time job it works fine.

Pete Deal said:

Mine never moved. In fact they stick in there pretty well. To remove I have a piece of wood that I put in the spindle end while changing collets, pads or whatever, and pop them out the back side. No issues there.

Click to expand...

Pete, sorry meant to say they move when you hit them with the bar putting the bar in. next thing you know you have them to close . Not spinning

Rapid_Tech said:

That's a new one

Click to expand...

yeah was a long long week.