Sharpening angles of 40 degrees and more on the T-8

[Scott B.]

Hi all,

New Tormek T-8 owner here.

I have a Two Cherries drawknife that came with a 40+ degree bevel.  I was thinking about regrinding it, but I really like the tight radii I can cut with such a sharp bevel.

However,  I am a bit stumped with how to set up the T-8 to replicate a 40 degree bevel.

I have the T-8, plus the hand tools kit and the SVD-186

Thanks,

Scott

[Herman Trivilino]

Hi Scott. Welcome to the forum.

You grind on only only one side of the blade of that draw knife, like you would on a wood chisel or a plane iron.

Do you have the SVM-45 knife jig? I think that's the one you'd use, set the Angle Master to 40°.

Alternatively you could color the bevel of your draw knife with a marker pen, and then adjust the angle until it removes the mark uniformly. This is called the marker method and is discussed in the Tormek manual.

If the knife jig doesn't work or you don't have one, you could try the SVD-110 Tool Rest jig.

[Scott B.]

Hi Herman,

Thanks.  I do have the jig.  My problem was that I could not seem to find the correct distance of the universal support to match the angle.

I was doing it incorrectly, I am sure, but I will keep at it.

I was trying to set it up to grind away from the edge and not into the edge. 

I have to dismount the honing wheels to clear space for the handles - but that is not a biggie.

[Ken S]

Scott,

Welcome to the forum.

I suggest you place your drawknife in the knife jig adjusted somewhere in the mid range. Cover part of your bevel with black marker. Eyeball the support to grinding wheel to get close. Without turning the power on, push hand push your grindingwheel a little to see if the black marker is being removed from the middle of the bevel. Once you are satisfied that it is, measure the distance on the jig from where it sits against the support bar to the edge of your tool. Record this number. Now record the distance from the top of the support bar to the grinding wheel. You now have the information you need to reset your jig to resharpen your drawknife for that bevel angle. You may measure it or make a kenjig. I happen to think the kenjig is the superior solution, however, I am ken.

Forty degrees seems very steep to me for a drawknife bevel. I do keep an open mind.

Ken

[Scott B.]

Hi Ken,

It is very steep, and I was going to reduce it - but when I was working on a project I found that the 40 degrees allows me to turn pretty small radii with the knife inverted.

I was shocked that it was sold with such and steep bevel.  The Froe I purchased suffered from the same issue. 

My feeling is that there are people out there making tools that have a basic idea, but not practical knowledge of how the tool is used.  Or they are just lazy and it is easier to grind a 45 degree bevel that a more refined edge.

What is a kenjig?

[Ken S]

Scott,

Your post gave me a good chuckle and made me think about Leonard Lee. I have a set of six Marples Blue Chip chisels, the models made without the beveled sides commonly called firmer chisels. These are for an undone project of regrinding them to a bevel angle of seventy five degrees. When quite sharp, this angle is useful for jobs like truing cuts on wooden planes.

Is the forty degree brvel angle on your draw knife a clever design feature for specialized work, or just cheaper to manufacture? I don't know. I have a pair or chisels with forty five degree skew angles. My gut feeling is that an engineer who had spent years "at the bench" might have chosen a twenty degree skew angle. Maybe the marketing boys thought a forty five degree skew "looked cool". 

On the other hand, I don't believe any bevel angle is "one size fits all".

A kenjig, not my word for it originally, is a simple gage I designed to simplify knife set up (not limited to just knives; it started out for chisels and planes) I posted a document I wrote describing it in depth with photos on the forum. It may be difficult to locate with search. If you send me an pm with your email address, I will email you the document.

Ken

[Elden]

https://forum.tormek.com/index.php?topic=2844.msg15166#msg15166

or as *docx

https://drive.google.com/file/d/0Bye-818SN85DdzB3bU9aUU81eTg/view

[Ken S]

Thanks, Elden! Moderators are a dime a dozen, however, a good forum research archivist is hard to find!

Ken

Scott, Check out Elden's finds.

[Herman Trivilino]

I have to dismount the honing wheels to clear space for the handles - but that is not a biggie.

That's to be expected for larger tools. It's designed for easy removal.

Are you using the WM-200 Angle Master to set the 40° angle? If so, follow the directions in the manual. Or search you-tube for "tormek angle master".

Alternatively you could use the marker method, also described in the user manual.

[Jan]

The draw knife has many uses and the bevel angle may reflect the intended use of the tool.

For shaving pegs of white oak for timber frame constructions an bevel angle of 25 to 30° may be used, while for green and soft wood some 20 to 22° may be suitable.

Jan

[Ken S]

Unlike chisels and planes, I do not recall a drawknife ever being used on wood wide enough to require the entire width of the blade. Spokeshaves, which are very much like smaller drawknives, are often set up such that one side of the blade takes a deeper cut than the other. This allows one tool to be used efficiently for rapid stock removal and lighter finishing cuts. Readjusting the blade to cut uniformly would take only seconds in skilled hands.

A drawknife could be sharpened with an intentionally varying bevel, thus allowing a single tool to be tailored for both soft and hard woods. Quite often a drawknife is sharpened with a small back bevel. If the stouter end of the blade bevel was created with a combination of a less acute angle on the bevel side and a slight back bevel, resharpening would require less metal removal. With a Tormek using the knife jig, the bevel angle might be ground uniform and a tapered back bevel  ground by hand.

This idea may be more appealing in theory than in the field. In the real world one would probably just have two drawknives, each with its own bevel angle or one tool kept very sharp. Sharpness is the great compensator.

Low angle (bevel up) bench planes often use several blades to achieve a wide variety of bevel angles. This helps prevent tear out with highly figured woods. In earlier times, it was common to have planes with standard pitch, (the frog which held the blade) at 45°; middle pitch at 50°; and York pitch at 55°. The bevel up planes often offer the ootion of blades ground with a very steep angle, with or without teeth, for scraping purposes. A single bevel up plane with multiple blades can be a very versatile tool.

As power tools have lessened the demand for professional hand tools, the number of available choices has lessened. In the past, a woodworker would have had the choice of half a dozen lengths of drawknives. He would have had a variety of chisels, including bevel, firmer, patternmaker and crank neck. Pity the poor metal worker in need of files. The local hardware store probably carries mostly mill files, and only files with bastard cut (the correct, acceptable term for a rough cut file).  to acquire a proper selection of files, which includes second cut and smooth cut teeth, he must deal with an industrial supply house.

Our tool industry has become homogenized. One size does really not fit all very well.

Ken

[SharpenADullWitt]

Ken, probably because the drawknife was before electricity.  Back when you might use the full thing, along with an axe, and adze with full size tree trunks.

[Jan]

Using the drawknife method in the UK were during the WWII manufactured many millions of tent pegs for the allied troops. They used beach wood. It was reported that they were done with 18 cuts only.

Jan

[Ken S]

SADW, you make an excellent point about the history of the drawknife exrenfing back to before power tool days.

Jan, you are correct in reminding us that the drawknife can be both an efficient tool for rapid stock removal and fine work with dispatch. It's largest potential constrsint is the skill of the user. 

Ken

[Herman Trivilino]

One of the things in my background that may be different from yours is that I grew up in a family with dull tools. My father had lots of tools, and some decent skills, but dull tools and knives seemed to be part of a way of life. A dull drawknife may have hung in the corner of some shed or shop, but it was neglected and for that reason never used. You restore the joy of working with old edge tools when you have a Tormek!