Need some advice on forming a precise hole on the lathe with chisels

[Burt25]

Ive decided to have a go at making some rings using stainless steel ring cores as the base. So Ive managed to make one successfully, but it now appears that was a fluke! Problem is I'm struggling to form the hole in my wood blank to take the ring core and the issue is that no matter what I try I cant get the hole cut without a slight taper, so on one side of the ring the fit is good, but there is a gap in the other side.

I'm using a combination of parting tool and Sorby multi tip hollowing tool and was wondering if there is another technique that I'm missing to ensure the hole sides are perfectly parallel?

 

[Penpal]

Care with precise cuts,sharp chisel,as you cut it will be clean or tapered hence the care factor.

Peter.

 

[Macaronytony]

Ive decided to have a go at making some rings using stainless steel ring cores as the base. So Ive managed to make one successfully, but it now appears that was a fluke! Problem is I'm struggling to form the hole in my wood blank to take the ring core and the issue is that no matter what I try I cant get the hole cut without a slight taper, so on one side of the ring the fit is good, but there is a gap in the other side.

I'm using a combination of parting tool and Sorby multi tip hollowing tool and was wondering if there is another technique that I'm missing to ensure the hole sides are perfectly parallel?

Hi Burt I have always wanted to try making a ring, I have a metal lathe so wouldn't have your problem. Can you tell me where you got the ring cores from?

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[Burt25]

Hi Tony

I got the cores from Woodcraftsusa (in Utah) they are 316 stainless steel, lovely quality and cheap!

Hi Burt I have always wanted to try making a ring, I have a metal lathe so wouldn't have your problem. Can you tell me where you got the ring cores from?

Sent from my SM-G920F using Tapatalk

 

[Burt25]

Hi Peter

Sharpness isn't a problem as I recently bought a Sorby pro edge and keep my chisel razor sharp I also constantly check size, but getting the hole sides parallel is a major challenge when 0.5mm makes the difference between a usable blank and scrap. Was wondering if i would be better with a csrbide with square cutter to do plunge cuts rather than parting tool? The other option is an expansive drill bit, but don't know how good these are on large?

Care with precise cuts,sharp chisel,as you cut it will be clean or tapered hence the care factor.

Peter.

 

[Burt25]

Hi Tony

I got the cores from Woodcraftsusa (in Utah) they are 316 stainless steel, lovely quality and cheap!

I meant craft supplies USA

 

[AllenN]

Two thoughts. When making small boxes I use a skew almost as a scraper and I also use a box scraper which allows minute adjustments to get a good fit on the lid. Might a very small box scraper do the job for you, I use a Sorby mini micro if I remember the name correctly but they are not hard to make.

 

[Macaronytony]

Thanks for the info....

Could you get close with the chisels then creep up on the size with a dremel drum sander..

 

[Burt25]

Thanks,

I was thinking this is box making type skill. The box scraper might work, but was wondering in a Sorby 6mm Bedan scraper would work better?
Bedan 1/4" (6mm)

The guy in the ring demo video has a scraper with bevelled sides I assume its a bedan tool of sorts but not sure- it seems to work well though:
Turning a Comfort Ring Core | Woodturning How-to - YouTube

Two thoughts. When making small boxes I use a skew almost as a scraper and I also use a box scraper which allows minute adjustments to get a good fit on the lid. Might a very small box scraper do the job for you, I use a Sorby mini micro if I remember the name correctly but they are not hard to make.

 

[Burt25]

Thanks for the info....

Could you get close with the chisels then creep up on the size with a dremel drum sander..

Might work Tony - problem is once you take it off the lathe it difficult to take the same amount of material off all the way round

 

[Dalboy]

When it is still mounted on the lathe and you are turning the centre out use the lathe bed bars or slides as a guide when looking at the shaft of the tool keep it aligned to these this will aid in keeping the cut straight, after a while it becomes second nature. Try this on some scrap wood first and see if it helps use a small off cut of copper pipe and see if you can get that to fit a hole that you have turned.
The other way is start the hole with a slight taper to the entrance is very close to the size required and keep test fitting the piece gradually straightening until the fit is just right.
The reason for the bevel on the side of the tool is so the cutting edge does the work without any other part of the chisel rubbing especially in such a small diameter it also allows for the cut to be nearer the centre height

 

[Penpal]

All the turning could be done,hole and all using a Bedan tool. I make my own Bedan using tool steel bought for making cutters for metal lathes, it comes in all sizes and lengths. From memory my ones came cut at 45 degrees,this I sharpen at 45 degrees. Most handy tool. I have some Hairy Oak cut 9 degrees across would make a champion ring. One time I bought space age material rings from the internet in America,borrowed one of my wifes current wearing rings and got the internal measurement, looked up Google and got the US conversion size. Worked a treat.

In the video I was intrigued by the guy glueing the timber on the Stainless ring using CA then saying don,t worry if it gets on the stainless it rubs off with a fingernail????????? Magic scuffing must be on the ring inside?Liked the rest of the Video though thanks.

Peter.

 

[Burt25]

It was the rubbing on the CA glue with his bare finger I didn't get

All the turning could be done,hole and all using a Bedan tool. I make my own Bedan using tool steel bought for making cutters for metal lathes, it comes in all sizes and lengths. From memory my ones came cut at 45 degrees,this I sharpen at 45 degrees. Most handy tool. I have some Hairy Oak cut 9 degrees across would make a champion ring. One time I bought space age material rings from the internet in America,borrowed one of my wifes current wearing rings and got the internal measurement, looked up Google and got the US conversion size. Worked a treat.

In the video I was intrigued by the guy glueing the timber on the Stainless ring using CA then saying don,t worry if it gets on the stainless it rubs off with a fingernail????????? Magic scuffing must be on the ring inside?Liked the rest of the Video though thanks.

Peter.

 

[Phil Dart]

In my experience, I've always ended up with a tapered hole exactly as you describe when ever using something like a parting tool or a bedan. The reason is that the circumference of the hole touches the top and bottom extremities of the shaft of the tool and forces it towards the centre. The answer, I have found, is to use something like an oval skew on its side, as Allen described, which has no height to it that can be affected by the circumference of the hole.

 

[wm460]

Interesting video Ian, thanks for posting.

 

[Bigblackdog]

I don't think that the bedan will help- the problem will persist. I would get the hole almost to size, ensuring that if there is any taper, the side nearest to the tool is the widest part. Then with the point of a small skew, cut the hole to the exact size to fit the core, but only 3 or 4mm deep. When that is sorted, take it down a little more, another couple of mm. Keep stopping the lathe and checking. hopefully, you can't go too far off. I would think that with care, you could shave a quarter of a mm off at a time.

could you rig something up to align the tool to. A long tool will exaggerate any angle, so you may want to make a very long skew for the task- it doesn't need to keep an edge for long- you could sharpen for each ring if necessary.

 

[Ray7756]

I understand you want to up your skill level with turning the hole, but in the meanntime why not just drill to the correct size ???
Cheers
Ray

 

[21William]

A round Skew chisel would do the job. Personally I’d do the job on my metalworking lathe using a boring bar.

 

[Macaronytony]

I did think of you using the dremel drum sander with the ring blank still on the lathe. Have seen it done in some of the youtube videos on ring making.

 

[Penpal]

A round Skew chisel would do the job. Personally I’d do the job on my metalworking lathe using a boring bar.

William you hit the nail on the head , Ian why not make an adapter to fit the woodlathe to enable a boring bar to do the job perfectly,when I was making my own mandrel saver I used the boring technique using a straight small endmill kicked on an angle to fine tune the entry to fit my mandrel saver.Utilise the rails on your lathe,make the device in timber if you want to pursue this in a big way make it in metal.After all ring sizes are a piece of cake compared with mandrel sizes. Use Google as a friend to see how woodies adapt their wood lathes to simplify and gain real accuracy in repetitive tasks.

Nthn Ireland is full of metal workshops and woodturners to see and find out how they do,suggest Wood groups as best value right now mate. Good luck.

Peter.