Milling a slot in a solid HSS blade..... and 60˚ bedding

[Matthew N. Masail]

So I just finished my first plane bedded at 60˚. it's a small prototype basically, first time making abutments (it's laminated) and bedding a plane so high.
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After making a small 52.5˚ smoother I was already thinking that I don't like how these planes are harder to push. after making this one I'm convinced I don't like it!
I can set the chipbreaker close enough to perform better than this plane bedded at 60˚, so why would I want a plane that's harder to push?

What am I missing? because people seem to love the HNT Gordon planes.

in any case as the first picture shows it works great with the blade bevel up making it a little scraper plane, it did a cracking job on this awful grain ( I know it dosen't look awful but this stuff just loves to tear all over):

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SOOOO.... I was planing on making a larger smother with a solid HSS blade bedded at 60˚, but now I don't want to. I have a plane blank with sides all ready, the blade is ready, but I'm not. I thought this would be
a great chance to learn how to make a chipbreaker, and bed the plane at 45˚. David Finck's book on Kernov planes explanins it very clearly, I just need to mill a slot in the blade....

Is there any chance I'll be able to drill thourgh it (it's 3mm thick)? with a special drill maybe? and then what? how the hell do you file somthings that's probebly 62-64RC if not more.?...

Just for the record, I managed to grind 2mm of the side of a HSS blade using a stationary belt sander and a 46 grit Zirconium belt (after being told it will be hell), and it went well, took only about 10-15 minutes, so please shine optimistic light on this ! :o

[Trevor Walsh]

IMO, you'd never drill through that with anything you could reasonably obtain. Send it out to be water jet or have an HSS blade made and heat treated is I think the only way to get what you want.

[Niels Cosman]

ditto on the waterjet. However, you could simply grind out a slot with a diamond or SiC grinding burr with rotary tool (a dremel or flexshaft ). It might take a bit of time, but it would get you your result and would probably cost less (a couple of $2-3 burrs) than a waterjet job.

[george wilson]

I very much doubt that a Dremel and diamond points are going to handle a HSS blade. Dremels have a really weak plastic coupling these days. I have had them fail a number of times on my little used Dremels. Mine is broken right now. Other than that,I doubt that the diamond coating on small burrs would do more than grind a dollop out of the HSS blade before the diamonds wore off.

If I HAD to do this,I'd have to use my milling machine and likely sacrifice a carbide end mill or 2 ( maybe more).

And,don't try milling in your drill press unless you want the chuck to come loose(unless it has a locking ring collar). Feeding the blade by hand would be very dangerous. I expect the blade would soon get so hot you'd have to let go. Don't risk a flat blade getting flung at you on edge. Is there a friendly machine shop available?

[Matthew N. Masail]

mmmm..... maybe more trouble then it's worth. I'm not sure what the equivalent of a machine shop would be here, but I'm not too keen on spending more, the only reason I thought to do this to this blade is because it's what I have. if I could afford it at the moment there is a cart all picked out waiting for me at Lee Valley.

would it be possible to just drill a 7mm hole and tap it with a 8mm thread? I'd then cut the slot in mild steel for the cap iron and make a slot for the screw head in the wedge rather then the plane bed. I suppose the trick would be to get the screw head to sit flush, meaning that I need to drill and tape the blade at a slight angle. does this sound more doable?

[Derek Cohen]

Hi Matthew

Perhaps I am just used to it, but I do not find the extra effort of a 60 degree bed to be significantly difficult to push. This may be that my blade is sharper, or the wood is slicker. Just as an experiment, using a freshly sharpened blade, try a little candle wax on the sole of your plane (a squiggle is sufficient).

Regards drilling HSS, forget it. Even if you could drill the metal - using a cobalt drill - it would be time consuming (you need to start with small holes and increase them progressively), and then you are still left with the problem of filing the holes into a slot.

You could look for a Mujingfang plane/blade to use. Cheap enough to sacrifice this way.

Regards from Perth

Derek

[george wilson]

NO,you cannot thread a hole in a HSS blade with a HSS tap. They are the same hardness. Think about it. You can drill a hole using a carbide tipped masonry bit. If you drill with it,it should be run fast. It melts the HSS out. BUT,if you drill TOO fast and hard,the brazed tip will get melted off. I always have to sharpen a masonry bit for EACH hole I drill in large HSS power hacksaw blades which are nearly 1/16" thick. If I don't,the brazing will melt in the next hole.

[Niels Cosman]

Hi George,
Should have clarified. I personally don't use dremel products (they are cheap crap) but i think it could be made to work. I have a foredom THX flexshaft, which I almost always use with a water feed. I have no doubt that this would work with the proper burrs and the proper grinding technique. The key when grinding anything ( especially steel) with diamonds is to keep the heat down and not grind too rapidly. Even cheap electroplated diamond burrs can be made to last years with vigilant attention to rpms and coolant.
something like this would probably give you the best result:
http://www.riogrande.com/Product/Diamond-Core-Drills/349005?pos=3
the hole can be ground with the business end of the core bit and then widened with the edges to make a hole or slot to any size you desire.

I have cut a notch out of a chisel (to make a bottle opener) in this way. I doubt that the metal was as hard as HSS, but diamond beats everything in rock, paper, scissor shoot! :)

[ian maybury]

HSS is pretty variable stuff (going from bloody tough upwards that is), depending on the alloy and the heat treatment. You hear stories of people pulling off small drilling jobs using reground carbide masonry drills, or solid carbide spade bits and going really slowly in a good quality machine with lots of coolant, but it's very borderline I think. It'll harden more or less immediately if it's allowed to get hot at all - even very locally.

Check before doing, but EDM (electric discharge machining http://www.mercatech.com/EDM%20Guides/EDM%20101%20-%20What%20is%20EDM.htm) will do it OK and without disturbing the heat treatment of the blade. Costs are for (a) making a copper electrode in whatever shape you need, and (b) actual machine time. If it's a large or complicated shape of slot a CNC wire EDM machine is possibly a better and more cost effective bet - these use a wire cutting sideways a bit like a fretsaw - but with XY control at both ends.

Quite a few well equipped tool making set ups will have this equipment, but it's not going to be cheap compared to buying a new blade...

ian

[David Weaver]

I don't know what your wood is like, but in the US little requires a 60 degree plane. The surface suffers quite a bit in comparison to a common pitch plane if you're going with a planed finish, and if you are working a smoother from a jointed or try planed surface, it's not very convenient. On the softer woods, it just doesn't yield a nice surface. On something like hard maple, it compares more favorably.

At one point, I had muji's smoother that's slightly higher than 60 degrees. I thought it was really great because you couldn't get tearout from it, but when I went to dimensioning wood by hand, I stopped liking it fast. It was appropriate only for light cuts.

[Matthew N. Masail]

Hi Matthew

Perhaps I am just used to it, but I do not find the extra effort of a 60 degree bed to be significantly difficult to push. This may be that my blade is sharper, or the wood is slicker. Just as an experiment, using a freshly sharpened blade, try a little candle wax on the sole of your plane (a squiggle is sufficient).

Regards drilling HSS, forget it. Even if you could drill the metal - using a cobalt drill - it would be time consuming (you need to start with small holes and increase them progressively), and then you are still left with the problem of filing the holes into a slot.

You could look for a Mujingfang plane/blade to use. Cheap enough to sacrifice this way.

Regards from Perth

Derek

Hi Derek,

I would assume safely that your blades are sharper, but I worked hard at it and got it super sharp (it cut me the first chance it had), then I waxed the bottom, and it's still much harder. could it be because these small smothers I made weigh only 300 grams or so..? my woodriver no.3 is 2.2kg.....
The blade I have is from the Mujingfang plane :) I got two.... I'm starting the think I should put them aside for the day I'll want to use them, maybe make a single Iron toted smoother or something.

It's starting to sound to me like I should just wait and get one of these http://www.leevalley.com/US/wood/page.aspx?cat=1,230,41182&p=66868. at least I'm learning quickly and didn't waste too much.

Niles that is just too cool! I don't think I'm going to spend so much time trying to mill the hole, I was hoping it would be simpler, but you got me in the mood for a beer! and I really appreciate the advice.

George, thanks for the tip, but I wouldn't know how to sharpen a masonry bit if it bit me :) I don't even know was it is... I know HSS won't tap HSS, I'm not that dumb, I just don't know what else is out there - I was thinking maybe some other kind of tap... I guess HSS is tougher than I thought.

[george wilson]

Thank you for the metal working lesson,Niels.:) I have very little experience with it.:) If he has to pay the cost of a Foredom,he might as well pay a machine shop to do the job properly. A Foredom flex shaft isn't the most durable thing either. I use a Dumore 1/10 h.p. hand grinder. My wife is always replacing the cables in her Foredom. It will do that job,but what does a Foredom with shaft and chuck run these days? $300.00 for a decent model? I haven't checked lately.

I think it would be a good idea to not advise the grinding of HSS unless a person has experience. It can contain cobalt,which is not good to breathe if removing significant amounts. It is also not only much harder than the chisel,but is also pretty tough in nature.

With all due respect,I will modify a worn out file to make something else out of it,but that is about as far as I'd go in defacing a tool,personally. We all have our different ideas,I know. I'm sure that is a cheap chisel,but I just can't bring myself to do that. Too OCD,I suppose !!

Ian,what you say about HSS and working is true. I have made several kitchen knives from large HSS power hacksaw blades though,and have drilled the blades for handle rivets with a cheap masonry bit,resharpening it on my diamond grinding equipment for every hole(or the blade will pop in half!!) I agree that it does require experience and finesse to pull it off,however. I think a machine shop would do this job better. Too much opportunity to mess up the blade.

[Stuart Tierney]

Umm, sorry to go against all the big brains here, but here we go.

Matthew, if you need to cut a slot in the HSS blade, use an angle grinder. The rough slot will take no more than a few minutes, cleaning up with drill mounted grindstones, files wrapped in SiC sandpaper will take more time, but it's certainly doable. Be careful with the angle grinder, and a smaller one will be better to make up as much of the slot as possible. As the wheel wears, work closer to the ends.

So long as the steel doesn't get over about 550°C, you won't affect it and if it does go above that temperature, you might well make it harder. I'm guessing it's a Mujinfang blade and they're not that hard and tough.

But back to reality, why? If it's that important to have a chip breaker, make one up and use it as the wedge for holding the blade in place. A chunk of steel with a few bumps at the blunt end will do it. A chip breaker does not need to be fixed to the blade, contrary to what most folks would have you believe.

Stu.

(Who's expecting to be called an idiot know nothing after this post...)

[george wilson]

Hss(there are many varieties) is tempered at about 1000º F.,so I doubt he'd get it hot enough to really hurt it. But,stirring up a bunch of dust to breathe just isn't a great idea. If I had it to do (except I have the equipment to do it better) I'd drill a hole with a masonry bit and make a brass insert that is made of round stock,say 1/2" dia. at least,with a short section turned down to fit through the hole. Then,insert the brass insert,and peen it over so it doesn't come back out of the hole. Countersinking the other side of the hole would be good. Could be done with a larger masonry bit.Doesn't have to be pretty. Peen the brass into the countersunk area. Leave the chip breaker side of the brass insert to be the flush side. Then,drill it and tap the brass insert. Many 19th.C. English planes have this type insert,and I've made them myself,except the brass part is in the chip breaker,not the blade. Now,a piece of 01 steel could be sawn with a slot and hole to reverse the normal situation. Then,a flat head screw with a large head could be used to secure the chip breaker.

Frankly,I think this whole deal is beyond what Matthew has the means to do. If you grind a little negative angle onto the cutting edge of the plane, blade,it will plane figured wood as well as a chip breaker anyway.

As for sharpening the drill,they are very cheap. Just use a new one for the next hole. They are about $2.50 in the U.S.A..

[Derek Cohen]

(Who's expecting to be called an idiot know nothing after this post)

Stu

You're an idiot :)

But I agree with all you posted. Smack my head because that's how I would do it. A hole is good to have at each end of the slot, but not necessary if it is difficult to drill.

Regards from Perth

Derek

[Stuart Tierney]

Actually, I think a hole in the blade with a brass insert peined into it and put the slot in any chip breaker would be by far the easiest option.

The Muji blades aren't that hard, and I did put a hole in one a while ago with a drill and lots of coolant. Needs a sharp tungsten drill though, burning through isn't the right idea I don't think. An off the shelf masonry bit with the cutting edges sharpened up would probably be alright, although the better the sharpening job the better off you'd be.

Still, I'd do a not attached chip breaker. Much like a kanna's chip breaker, except make it do double duty of being the blade's wedge too.


Derek, takes one to know one. ;)


Stu.

[george wilson]

I have used an off the shelf masonry bit many times,so have actual experience. It does heat up the HSS until the temper is destroyed right around the hole,but only right around the hole,about 1/32" out. Sharpness is not exactly the right word,but the drill needs to not have a rounded off cutting edge. Really getting a sharp edge would require much finer lapping methods than the average guy is going to have,and it depends upon the grade of carbide,too. Actually,it works better if you grind a negative cutting angle onto the bit,but that takes a diamond grinding wheel- or a good stretch at a diamond bench stone.

This process is not at all unknown to machinists,but is not the most approved method,I must say. But,for the home shop guy with limited budget it will work. The really correct drill to use is a straight flute solid carbide drill,or the carbide spade drill, but they aren't found in the local hardware store,and cost many times more. I drilled my last HSS holes with one,but drilled all the others with the simpler masonry bit.

The way I found out about this was many years ago,I was at a woodworking show. This guy was demoing some German drills by drilling many,many holes right through 12" files. They looked like Swiss cheese. I suckered in and bought a set in the excitement of the moment. Later,I looked at them and discovered that they were regular masonry bits with a negative grind on their cutting edges. They did drill HSS power hacksaw blades,but they drilled those files a LOT easier. The files had a much lower temperature at which they became softened so the metal could be scooped out by the drill. As I mentioned,HSS is tempered at about 1000º,a lot higher than regular carbon steel. That is they they literally can get red hot in a lathe and continue to cut mild steel. That's why it is called HSS. The lathe can run and cut a lot faster with HSS bits.

Years ago I saw an ad in a Popular Mechanics magazine showing an acetylene torch heating a HSS bit red hot while it kept cutting. The HSS stayed hard even at red heat. When this metal was invented,it caused the current machine tools to become obsolete. The shop down the street could out bid you if they had lathes that could run faster,and do the work in less time. Time is money in competitive businesses,so lathes with better bearings replaced the older models. The same thing happened later on,when carbide was invented. Old machines could not compete.

[ian maybury]

Wondering if the discussion is at cross purposes. Are we talking slot as in elongated through hole here, or slot as in groove in a surface? Neatly formed with square sides, or not? Also if 'HSS' in this context is the same sort of stuff as in e.g. a lathe cutting tool, or something else?

ian

[Niels Cosman]

Thank you for the metal working lesson,Niels.:) I have very little experience with it.:) If he has to pay the cost of a Foredom,he might as well pay a machine shop to do the job properly. A Foredom flex shaft isn't the most durable thing either. I use a Dumore 1/10 h.p. hand grinder. My wife is always replacing the cables in her Foredom. It will do that job,but what does a Foredom with shaft and chuck run these days? $300.00 for a decent model? I haven't checked lately.


George, you work metal too? I had no idea! :):):)
Of course, I certainly wouldn't presume to lecture you on the subject of which I only have tangential experience.
Foredoms, certainly aren't cheap and I certainly have my gripes with them. I for one wish they would offer at least one rust resistant handpiece for use with water. I used mine mostly for glass work and tool resoration, with lots of water. For personal use it's not a problem, but in a school shop setting I have to rebuild handpieces/chucks once or twice a year. The cable maintenance can be a drag, the industrial model cables are beefer. They are also longer which can be a bit of a inconvenience to manage at a bench. I have mine hung from the ceiling with a tool-balancer that can be adjusted to take up the weight of the excess cable.

[Jim Matthews]

I wonder if the mouth opening is contributing to drag?

If the chip isn't ejected, won't that make things slow down?
My favorite HNT Gordon has a brass plate, in front of the mouth.

I needed a couple fettling passes with a file to let the shavings through.

I'm also suspicious of the attack angle on the plane blade.
If there's a microbevel in addition to the bedding angle, the point of contact is pretty steep.

[Matthew N. Masail]

I wonder if the mouth opening is contributing to drag?

If the chip isn't ejected, won't that make things slow down?
My favorite HNT Gordon has a brass plate, in front of the mouth.

I needed a couple fettling passes with a file to let the shavings through.

I'm also suspicious of the attack angle on the plane blade.
If there's a microbevel in addition to the bedding angle, the point of contact is pretty steep.

Mm... You may be on to something.... I sharpen using the ruler trick, and sometimes I cheat and just do it by hand, but I was under the impression the this tiny micro bevel doesn’t effect the cutting angle.

[Derek Cohen]

Hi Matthew

A back bevel on a BD plane adds to the angle of attack. So, if you had a 10 degree backbevel, the angle of attack with a 60 degree bed would be 70 degrees. Now that would be hard to push, waxed sole and all.

It is only a BU plane where the back bevel does not add to the angle of attack.

Regards from Perth

Derek

[Matthew N. Masail]

Hi Matthew

A back bevel on a BD plane adds to the angle of attack. So, if you had a 10 degree backbevel, the angle of attack with a 60 degree bed would be 70 degrees. Now that would be hard to push, waxed sole and all.

It is only a BU plane where the back bevel does not add to the angle of attack.

Regards from Perth

Derek

Hi Derek,

I know logically that it adds, but I have read that with the rules trick it's too small to matter. so that's wrong? I'll try to sharpen with a flat back and see what a difference it makes, but I have a hard time flattening a back, not to mention on HSS with the crappy stones I have. I really need to get a decent set.

[Derek Cohen]

Hi Matthew

The Ruler Trick only add 2/3 of a degree. However you said you freehanded the back bevel, and it is possible that you added a lot more angle than you realise! Possibly as much as 10 degrees.

Regards from Perth

Derek

[Matthew N. Masail]

Hi Matthew

The Ruler Trick only add 2/3 of a degree. However you said you freehanded the back bevel, and it is possible that you added a lot more angle than you realise! Possibly as much as 10 degrees.

Regards from Perth

Derek

Ohh.. I see:o I'll stick with the ruler and see. it any case, I think I'd rather build at 45 or 50 like my jointer. they glide thourgh the cut really nicely.