Holdridge radius turner

Hi gang,
Anyone have or are familiar with the Holdridge radius turning jig.
I have been kicking around the idea of making a radius turning jig, I like the Holdrige design but could not come up with an easy way of making the frame. In the work shop under my house which I now call the Tardis from Doctor Who, as all the family think it has never ending space i.e. Just put it under the house. Camper trailer and too much non work shop crap. I remembered I have the outer and inner race from a large bearing, OD say 200 mm, I can cut both into C s with the angle grinder to use for the frame. So this is my question to weld fixtures to them and drill holes how should I go about it. Weld with Tig and say use stainless filler, to drill heat to anneal?. Food for thought to get the cogs turning.

If anyone has one gathering dust let me know. I have a brand new Japan made auto reversing tapping head for a drill press or mill that I need to trade sell.

Cheers
Bruce

Hi Bruce,I have one that came with the mars lathe. I have put some pictures up on the forum before but I can't remember where. I'll put some more photos up later when I'm not on my phone.Cheers,Ew

Is it this thread Ewan?
https://www.woodworkforums.com/f65/ball-tool-163049

Michael

Couldn't see it there Michael. I put it up for handlebar Phil at some stage.

Any way, here it is. Looks like it may have come with the lathe from new, but who knows. The problem with this style of ball turner is the lack of rigidity if you want to turn concave surfaces.

Ew

Hi Guys,

I've made a couple of variations on both those themes ! I've come to the conclusion that the "up & over" type is as good as any. Its certainly easier to make, though like all the others does have its issues.

Ew,
Do you have the inserts for doing concave. In both cases convex and concave are they held into the main frame by a pin at the bottom then a set screw to lock the pin. Like wise at the top it looks like the driving shaft is squared at the end where it enteres the C or straight insert and a set screw again to lock in place. Bushes in the main frame?
Cheers
Bruce

I have a couple different radius turning attachments, both home made. One is a similar design to the Mars and another for concave. They have both been welded together rather than much machining. I looked at the link trail and followed to the Steve Bedair Ball turning toolpost. That looks good and I am thinking buying a cheap boring head and making a rotating base for it and a toolpost could save a lot of work. I guess it depends on the motivation for doing the job, to get it done or spend the time to make a good tool.

Ok, so i guess i am missing the concave cutting bar. I guess that it is just a straight bar.

As the frame is CI there are no bushes, but if you are using steel then a CI or bronze bush would be the way to go. I'll take some more detailed pics of the pivot points later on.
Ew

I picked this up on the weekend.Once i figure how to mount it.
it should make a nice radius turner.
sorry about the photos i have no camera at the moment.
Attachment 308358
Attachment 308359
Attachment 308360

Quote:

---

Originally Posted by azzrock

I picked this up on the weekend.Once i figure how to mount it.
it should make a nice radius turner.
sorry about the photos i have no camera at the moment.
Attachment 308358
Attachment 308359
Attachment 308360

---

Aaron,
Great find! Looks made for the job, and useful for other things like radius milling.
Do you know its original purpose?
Cheers,
Bill

Quote:

---

Originally Posted by WCD

Aaron,
Great find! Looks made for the job, and useful for other things like radius milling.
Do you know its original purpose?
Cheers,
Bill

---

hi Bill how have you been mate. I don't know much about it not even where it came from.
the guy i brought it from ill ask a few questions next week.
Its very well made moves smoothly and has the two stops that are adjustable.
I think ill make a block for it and mount it to the cross slide of my colchester
the same way the compound slide is mounted.
aaron

Hi Ew,
I recon the inner C in you Holdridge is an add on, as they are normally cast.
Cheers
bruce

Quote:

---

Originally Posted by azzrock

I don't know much about it not even where it came from.
the guy i brought it from ill ask a few questions next week.
Its very well made moves smoothly and has the two stops that are adjustable.
I think ill make a block for it and mount it to the cross slide of my colchester
the same way the compound slide is mounted.
aaron

---

This looks vaguely similar: http://bbs.homeshopmachinist.net/thr...132#post911132

Quote:

---

Originally Posted by variant22

This looks vaguely similar: http://bbs.homeshopmachinist.net/thr...132#post911132

---

HI MATE im not shore if that's the right link.
ive made something similar to that.

Attachment 308568