As I got great advice about handplanes, perhaps the hand tool afficionados of Knots will also advise me concerning a scraper?
The greenwood chair making course I went on introduced me to shaped scrapers, albeit rather primitive ones made of old sawblades. My tutor had half a dozen, shaped for various chair parts.
Being a consumer at heart (and bereft of old saws in any case) I bought a Lee Valley (yes, I’m a pathetic fan of theirs) four-sided scraper on a ball and joint handle. The blade is 3 inches square and made of High Carbon Steel. The handle and ability to set it at various angles will help a lot with sometimes awkwardly angled chair parts held in the mare.
I would like to modify 3 of the four straight edges of the scraper so that I have: a concave half-round of 2 inch diameter; a concave half-round of 1 inch diameter; and a convex edge of about 6 inches diameter.
My question is, what is the best and quickest method to cut these profiles into the scraper without damaging the temper of the HCS and to create neat, regular curves that can be succesfully square-edged and burnished?
Thanks in anticipation.
Lataxe
Replies
never having done this meself I'm sayin up front that this is pure guesswork..
Personally I'd look first at Mk1 hand files.. should be able to match any pattern you want with them without giving the temper a hard time.. I'd steer clear of grinding wheels (mainly cos I don't have one)... speed generates heat, heat blows temper unless you frequently cool the workpiece with a quick dip in water... Things tend to go wrong in a hurry with power tools... hand files will let you creep up on the desired profile...
Mike Wallace
Stay safe....Have fun
A bench grinder can do what you want as long as you take your time and dip frequently in water to keep the blade cool.
The low tech way would be to use files and your vice while sipping your favorite beverage.
QCI,
Were I to be sipping my favourite beverage, I wouldn't be near a tool, even a simple file. It would end up in my foot or a worse place, although I might not care until next morning. :-)
Being lazy, I was hoping someone would say, "Drill it with a bimetal hole saw in this fashion" or similar. I suppose hard work is going to have to be performed. I wish I had a shed-slave.
Lataxe
"Were I to be sipping my favorite beverage, I wouldn't be near a tool,"I should have said "Britian's Four O'Clock Beverage", because I was referring to tea. The alcohol in the shop is for the shellac. OK maybe one beer on a hot day if I'm sanding. And it's only that one because in spite of what you may have heard, I'm not all that fond of beer.If you have a spindle/bobbin/drum sander it might speed up the process slightly but the files, as I mentioned, is the way to go.
Thank you all for the advice. Files it is, although the bandsaw preliminary is tempting.
QCI, I have hear nothing about any of your habits, even the bad ones. Perhaps you would like to 'fess up in your profile. :-) Of course, all my bad habitsd were long ago knocked out of me by the ladywife - except for (censored by the good taste police).
Lataxe
Quite honestly it would be much more straightforward to anneal, shape and re-harden. With scrapers I would not worry too much about temper. After all some folk cut glass for the same purpose.
A blow torch in my experience does the trick.
The end hardness of scrapers should be in the RC 50 range. You should be able to simply file your desired profile. Good files are wonderfully magical tools. You can hog material incredibly fast or you can draw file for a near perfect finish with the shavings looking much like very fine steel wool.
I'm with Larry.
A nice sharp file, a firm backing to avoid chatter, and you'll get there quickly, cheaply, and precisely. Draw-file smooth.
Malcolm
File the profile.Mark the outline with fine tipped sharpie and commence filing.Hold file tightly in left hand while sipping beverage with right hand.The file will not land on your foot.The beverage might though.
mike
If you have a band saw and lots of material to remove, a band saw (with a metal cutting blade) will do the job quickly, and then you can finish the shaping with files and slip stones.
James
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