Finishing the inside of end grain boxes

[Rhossydd]

Coming back to turning after a few years away, I've remembered quite how awkward it was to finish the inside corners of small (2"-3" dia.) end grain boxes.
There now seem to be a few specialist tools available for the task, has any one any experience of them and can offer any opinions on them please ?

Robert Sorby 829H Box Scraper 3/4";
Looks simple and rigid.

Henry Taylor Jason Breach 3/8" Square Taper Tool;
Looks solid again, but I've no experience of using or sharpening negative rake scrapers. Are there any special techniques for this ?

Robert Sorby Box hollower 803H;
Interchangeable tip tool with a flat shank. Not sure I like the whole idea of interchangeable tip tools, but this does at least look easily usable and versatile too.

Or am I better off just getting some scrap old scraper and grinding away at it until I get something suitable ? ;-)

 

[Spindle]

Hi

I have the Robert Sorby box scraper - it does exactly 'what it says on the box', however I think it's a bit of a luxury tool. As you have indicated, I could have re-ground a normal scraper or even a HSS tool bit to achieve the same end for less outlay.

I don't have the Sorby box hollower but I do have several other replaceable tip tools - I always feel they lack a bit of mass at the business end.

With the benefit of hindsight I think I'd make my own tool should the need arise in the future.

Edited to add that a bedan makes a pretty good tool for cleaning up the bottom internal corners of boxes and is more versatile than a dedicated scraper - if you don't own a bedan I'd give adding one some consideration.

Regards Mick

 

[yorkshirepudding]

I recently bought a Simon Hope hollowing tool. An excellent tool which doesn't cost the earth.

 

[tekno.mage]

I make loads of boxes and mostly use a normal 3/4" scraper ground to a sensible corner shape for the inside of a box - ie it's a slightly softened 90 degree corner and I sharpen it along the left edge as well as across the front edge. Works fine for most of my boxes. I also have a tool bought as a "box scraper" which is a 1/2" diamter steel rod ground to a sharp 90 degree corner and again sharpened across the front edge and the left hand edge which is handy if you want a really sharp bottom corner in a very small box. This one allows for ease of shear scraping the bottom of a box if desired as it is a round bar and can be held easily at whatever angle you need.

I'm personally not a fan of tools with interchangable tips - I couldn't be bothered with all the faffing about changing the ends over or adjusting them - and there are all those small parts to get dropped and lost in shavings! I much prefer to have a tool for each job - and grind it to the shape I need if required.

 

[chipmunk]

+1 for the comments of Kym and Mick.

A bedan is a useful tool because the "eased" left-hand side will run down the inside of the box and not interfere with cutting into the corner. This is an essential feature of box scrapers IMHO.

The Gary Rance box scraper is worth considering which is the round bar tool Kym talks about. The problem with these is that the section of rod which is ground flat can chatter if it's long like this if you take heavier cuts...

I find it's often better to grind a 1/4" or 3/8" round bar with a flat on the top to the half-way point (say 15 degrees) to create a negative rake top face and then sharpen the front edge as the Rance box scraper. That way you have much more meat close to the cutting edge to prevent chatter.

The other scraper I use a lot for small boxes is a 1/4" square shafted tool with the lower left hand corner ground away so it comes close to having a quarter circle cross-section. This is a favourite of Chris Stott.

HTH
Jon

 

[Rhossydd]

Thanks everyone so far for their advice and opinions. keep 'em coming.
Re-profiling a cheap scraper to exactly the shape I require seems the most cost effective way to go at the moment, but some of the specialised hollowing tools may be worth a look sometime when I'm back up to speed.
The Bedan also looks to be well worth further investigation.

No opinions on negative rake scraping though ?
Possible a bit expensive/wasteful to just experiment with ?
Just how little would you need to relieve the cutting edge to get the effect ?
The Jason Breach scraper seems to take the bevel a long way back, wouldn't you get the same advantage(if any ?) with just a couple of mm bevel ?

 

[sammo]

Hi - I have the Jason Breach scrapers - the round nose one and the box shaped version, both negative scrape, and have to say both do a great job - the box scraper I have not used that much, but the round nose one is very good - it finishes well, especially when used in the shear scrape mode.

 

[Robbo3]

If you don't want to buy a specific tool, just use the skew on its side. More than adequate as long as there isn't too much overhang.

 

[Rhossydd]

Thanks again to everyone for their help on this.
I decided to go down the DIY route on this and picked up a cheap scraper from Axi yesterday, £12.80 3/4" round. The scraper is just about the cheapest wood turning tool easily available here, with 3/4" x 1/4" HSS to work with it was solid enough for what I wanted. About 16" in total with a half decent handle too. Just the right size for this sort of task I think.
I started by grinding most of the curve off, stopping frequently to avoid over heating and to get the varnish(cack)* off the surface frequently and get a decent(ish) finish on top and bottom. As you should be able to see from the attached photo I've ground the end to about 85deg (with a slight curve) to the LH edge with a small diameter radius on each corner. I've also ground a scraping edge on the left of the tool too.

Not perfect, but will be improved a little each time I re-sharpen.

My first use of the tool was with a small Imbuya box. Initial bulk was taken out with a small bowl gouge and a medium square edge scraper, the I used my new toy to refine the shape. It worked exactly as I'd hoped. Nice smooth tight radius corners in the box with the ability to work a smooth transition onto the sides, also the curve on the end face allows a nice curved base too. Sorry, but the photo doesn't show this too well. Photographing small curves on teh inside of dark wooden boxes is a skill I'll need to improve on ;-)

*Worst aspect of this particular tool is the stuff they coat it with to protect it from corrosion. When the tool is being ground it smelt awful and worst of all, being like paint it's slightly soft and a bit, well, tacky. Trying to slide it along a tool rest when scraping wasn't smooth at all. It really needs it all cleaned off before use. I can imagine a few beginners being off by the effect if they don't do some tool fettling before use. You can see some residues on the top face of the above photo.

 

[JustBen]

*Worst aspect of this particular tool is the stuff they coat it with to protect it from corrosion. When the tool is being ground it smelt awful and worst of all, being like paint it's slightly soft and a bit, well, tacky. Trying to slide it along a tool rest when scraping wasn't smooth at all. It really needs it all cleaned off before use. I can imagine a few beginners being off by the effect if they don't do some tool fettling before use. You can see some residues on the top face of the above photo.

What is the coating they put on the tools?
It feels like a wax of sorts.
It's a pain to remove.
My best solution was thinners and wire wool but even that took some time.

 

[Rhossydd]

What is the coating they put on the tools?
It feels like a wax of sorts.

Not sure about a wax it doesn't liguify with heat when grinding, it just smoulders. I reckon a cheap lacquer or varnish.

It's a pain to remove.
My best solution was thinners and wire wool but even that took some time.

To avoid clogging my sharpening stones, I used some little diamond file cards. maybe a solvent approach might have been more suitable.
Being somewhat soft it really doesn't come off at all easily.
I think it will take another quarter of an hour's work before the underside of the tool is clean and smooth enough to slide nicely on a tool rest.

Worth the effort though

 

[Spindle]

Hi

Whilst you are working on the bottom face of the scraper it may be worth easing the sharp corners with your diamond file, this will ensure they don't catch on the tool rest.

Glad you're pleased with your custom tool making and its result =D>

Regards Mick

 

[Rhossydd]

it may be worth easing the sharp corners with your diamond file, this will ensure they don't catch on the tool rest.

Actually the edges aren't the 'ouch I could cut myself on that' sort of squareness that some scrapers seem to have. Now the nasty lacquer/varnish/cack has been removed it slides sweetly on the rest.
Overall very happy with the end result. Just need to get stuck back into improving my technique after so long not turning.

Paul

 

[JustBen]

I tried TFR, white spirit and then thinners.
The thinners took about 5 minutes with wire wool.
Still, that's 5 minutes less on the lathe.