Making your own cabinet scrappers.

[xy mosian]

As you are working on the inside of a coopered panel. I think it would be a mistake to either have made, or make, a scraper to match the curve exactly. It will be a lot easier to use if it has a smaller radius. This will allow 'wiggle' room and sloping of the blade to, perhaps, get better results from the burr.
xy

 

[simonms]

Yes, obviously the scraper won't pass over the curve at 90 to it, I made some sanding blocks to fit the curve but slight under shot the radius and that worked ok on the last ones I did but just thinking about how to improve the process as the scraper left very a nice surface finish.

 

[Bod]

I think you will find a scraper of that length will be very difficult to use.
Possibly better to use a standard Goose neck, or have indivdual radius ones made, to a size that you can use comfortably.

Bod

 

[That would work]

No you haven't, Woody has suggested making my own from old hardpoint handsaw or and old bandsaw blade (cheers Woody) but I have nothing like this to use. I was interested in what type of steel was used to make these things so I posted this link.

https://www.steelexpress.co.uk/toolsteel/

Mike, every time I post here I get this sort of low level intolerance from you, I won't rise to it as I have said before, maybe take a walk or have a cup of tea.

If you don't have anything to make scrapers with now why not pick up one or two old cheap handsaws off ebay and they would most likely be better than a hardpoint saw.

 

[simonms]

I think you will find a scraper of that length will be very difficult to use.
Possibly better to use a standard Goose neck, or have indivdual radius ones made, to a size that you can use comfortably.

Bod

I am not suggesting one single scraper for the entire curve but maybe 5 or 6 smaller ones to accommodate the radius, sorry for any confusion.

 

[owen]

Where are you in the country? I've got loads of old saws you can have if you're anywhere near Buxton Derbyshire

 

[Woody2Shoes]

I think you will find a scraper of that length will be very difficult to use.
Possibly better to use a standard Goose neck, or have indivdual radius ones made, to a size that you can use comfortably.

Bod

I am not suggesting one single scraper for the entire curve but maybe 5 or 6 smaller ones to accommodate the radius, sorry for any confusion.

I'm confused, you do use a scraper slightly bent anyway don't you? I was thinking of converting your existing straight edge scraper into something like this: https://blog.lostartpress.com/2019/03/2 ... rved-work/ you should only need one of these.

See also: https://www.brilliantdiy.com/card-scraper-and-holder/

 

[MikeG.]

.......I am not suggesting one single scraper for the entire curve but maybe 5 or 6 smaller ones to accommodate the radius, sorry for any confusion.

One is plenty. Seriously. When planing a flat board, the plane blade has a slight curve to it. It is the working it continuously across the board which flattens things out. Same principle with a cabinet scraper. Microscopically, the board is left with a series of minute corrugations, far too shallow to ever see or feel. Your barely curved surface needs a barely curved scraper of tighter radius, just, than the tightest radius of your work, and you just need to use it a lot. There is frankly no other practical way of doing this job, and it is the correct way.

 

[simonms]

"Your barely curved surface needs a barely curved scraper of tighter radius."

I think this is exactly right, I was finding that the radius on curved scrapers was too much and with square scrapers with a bit of bend in use was hard on the hands and easy to drag the 90 degree edge into the work piece although I guess I could easily round the edges. Cheers Mike excellent advise.

 

[Woody2Shoes]

"Your barely curved surface needs a barely curved scraper of tighter radius."

I think this is exactly right, I was finding that the radius on curved scrapers was too much and with square scrapers with a bit of bend in use was hard on the hands and easy to drag the 90 degree edge into the work piece although I guess I could easily round the edges. Cheers Mike excellent advise.

You might find it illuminating to read the rubric here: https://lostartpress.com/products/crucible-card-scraper

 

[Sgian Dubh]

I guess I am just interested in methods to get the best results and wondered if making scrapers to match the piece might be worth considering.

Probably not for a gentle arc like that (shown in one of your earlier posts) with what appears to be quite a long radius.

I made some sanding blocks to fit the curve but slight under shot the radius and that worked ok on the last ones I did but just thinking about how to improve the process as the scraper left very a nice surface finish.

In your situation, I'm almost certain I'd do the same again, starting with either 80 or 60 grit and work my way up to something like 180 grit prior to applying a finish. Alternatively, and a lot quicker in my experience, I'd do as I've done many times before, which would be to dig out my random orbital sander, attach a soft pad, and go at it, again starting at probably 80 grit (maybe 60 if it's pretty rough) and work up to 180 grit, all on the ROS. I sometimes finish off with a bit of hand sanding with the grain at 180 grit, just holding paper in my hand. Works for me, see below.

There would be nothing wrong with using a scraper, plus sanding to prep for polishing, but with such a gentle curve I don't think you'd need to make one. I strongly suspect a standard rectangular scraper could be bent sufficiently to accommodate the arc you illustrate. Still, my choice would send me to the ROS - I'm all for speed and keeping costs to the customer down if I can. However, if you want to make your own scraper at some point it's pretty easy to do, as others earlier in this thread have described. I can't help with a supplier of new steel, except to suggest you could maybe haunt somewhere like eBay, junk shops or a car boot sale or two to find yourself a badly mistreated and usalvageable clunker hand saw or similar, ha, ha. Slainte.

 

[MikeG.]

I like the square pedestal, Richard. I think we may have seen that a year or three back, didn't we?

 

[simonms]

Thanks for the detailed reply, I have tried using a ROS with an interface pad but it leaves un even results but with a bit of further sanding with the profiled blocks it could be iron out. I was hoping a scraper might be a good method of evening out.

 

[mrpercysnodgrass]

I make scrapers out of glass for one off projects, they do leave a slightly textured surface that needs finishing with sandpaper but for accuracy cheapness and speed you can’t beat them. If you have a drawn outline of the curve simply place a piece of 2 or 3 mm glass over it and score the glass, you then have the perfect shape and the cut glass has a natural burr cutting edge. I wear gloves when using glass scrapers as they can break quite easily but are also easily replaced!

 

[Sgian Dubh]

I like the square pedestal, Richard. I think we may have seen that a year or three back, didn't we?

Correct Mike. However, there were problems with it after installation. There were five laminations in it. Glued with urea formaldehyde adhesive, and lots of clamps after careful preparation of the faces. Everything was hunky-dory in the workshop as the table was made, and still good after completion and stored for a few weeks in a similar cool but dry environment. They lasted only about four weeks in a house with some sort of highly sophisticated climate control system (way beyond simple A/C, heating, double glazing, insulation etc: can't recall the name of the system now, but I imagine you'll have come across it being an architect) before some delamination occurred.

I've never been able to definitively put my finger on the cause of the failure. The wood was about 10% MC during construction, and probably it gained a bit during making and storage. Could it have been the fancy climate control in the house causing significant drying and shrinkage? Could it have been the urea formaldehyde? Maybe, because, like others, I noticed the stuff didn't mix and behave in the same way it used to twenty or forty years ago. Would a creepy PVA or aliphatic resin have been a better choice? Those types weren't chosen because of their limited open time, compared to the UF Extramite brand.

Anyway, it's puzzled me ever since, and I like to think I'm pretty good at understanding wood's behaviour with a pretty good understanding of construction. Whatever, it's made me wary of taking on further jobs requiring such chunky laminated structures: smaller ones, no problem in my mind; but big ones .... hmmm, er, maybe, with a 'you've been warned of a possible consequences/failure' rider for the client, ha, ha. Slainte.

 

[MikeG.]

........ some sort of highly sophisticated climate control system (way beyond simple A/C, heating, double glazing, insulation etc: can't recall the name of the system now, but I imagine you'll have come across it being an architect) before some delamination occurred..........

I imagine that's probably an MVHR system in a super-insulated house (Passivhaus, maybe). They do produce a remarkably stable internal environment, with temperature and humidity hardly varying at all either on a day-to-day basis, or across the year. You're looking at a daily temperature variation in the region of half a degree, generally. Obviously that does have implications for wooden furniture, and it is hard for a furniture maker to adequately prepare for those conditions. I reckon the best solution would be some sort of finishing kiln in the workshop, with a little bit of heat (I did say little!) and a dehumidifier. A musician friend of mine has an expensive grand piano sitting in a barn (an occasional concert venue), and I helped him construct what is effectively a kiln around it, with a few sensors controlling a greenhouse heater, some incandescent bulbs, and a humidifier/ dehumifier. It cost no more than £200, and I reckon it could be set to replicate any house internal conditions. I can't think of a better way of firstly conditioning the timber for a project, and then the completed piece of furniture prior to hand over.

Sorry simonms, for the diversion.

 

[MikeG.]

I make scrapers out of glass for one off projects.......

I've seen African craftsmen who have nothing but a sharpened screwdriver and some pieces of broken Coke bottle produce some fantastic work, and even in the better woodshops the table tops etc will be finished with a piece of glass.

 

[Sgian Dubh]

... MVHR system in a super-insulated house (Passivhaus, maybe).

That description rings a bell, Mike. Very small variance in temperature and humidity, recovery of heat, and all that sort of thing. All of that may have been the primary cause of the failure, but I can't say that definitively. There could be another contributory factor or factors. It remains a bit of a puzzle.

You discuss your friend's piano and your set-up to look after it, and mention incandescent bulbs. I used the same bulb idea to keep my toolboxes and tools within dry and rust free in damp workshops. They broke on a fairly regular basis, which was annoying, and eventually I went to Farnell and bought a few small cabinet heaters as in the link below. They've been running continuously now for several years, maybe six or seven without needing replacement: they might be worth a look for your friend, and perhaps other circumstances. Slainte.
https://uk.farnell.com/pentagon/ach20-2 ... dp/3183166

 

[worn thumbs]

I remember the original items that this thread relates to were discussed at length a long time ago.The simple answer is to buy a set of curved scrapers and get on with the job.This sort of set crops up online from time to time and is a useful start.

Maybe not perfect for the curve in question but you need to get used to the idea that few curves identical to your existing scrapers ever will crop up and you flex them or lean them over a bit to get the job done.I would definitely not advocate having a custom shape CNC cut as the normal sheet metal processes of lasering or waterjetting might not leave the edge in an ideal condition for sharpening.If I absolutely had to produce a curved scraper for umpteen square metres of uniformly curved surface ,my first call would be the council tip as they sell old tools for about £2 each and there is normally a panel saw or two in the box.A bit of time with a quality hacksaw blade and a half decent file would get the job done.I don't think I would go looking for a burnisher made of specially treated unobtanium either there is a niche business selling such trinkets to keen hobbyists.The corner of a chisel works well enough and a scraper that is super hard might hold an edge a bit longer but it also takes a bit longer to re-sharpen.

 

[Racers]

Hardpoint saw, grinde,r file, burnisher job done.

Spoon and egg shaped scraper by Racers, on Flickr

Pete