Sunday Round Table Jabber - Sunday evening all welcome

[Bushmiller]

Christies sold a set of six zig zag chairs in elm with brass bolts on 3 November 2015 for £28,750 - about Au$63,000 with buyers premium.
GERRIT THOMAS RIETVELD (1888-1964)

The accute mitres seem to be reinforced by the brass bolts and there is cross-bracing behind each such mitre. Like Paul and Neil, I am wary of the engineering - it looks like it was designed to fold. And its not available at Ikea!

Graeme

Six chairs that were manufactured in 1968 rather than 1932 so not what I would have considered original. That's a lotta money!! Looking more closely at the design and seeing the set of six, it seems to me that they were in fact intended as dining chairs, which makes more sense of the rather upright and not overly comfortable seating position. Yes, I still don't see the design as robust.

Regards
Paul

[GraemeCook]

Graeme

Six chairs that were manufactured in 1968 rather than 1932 so not what I would have considered original. ...

Yes; and they were made by a different bloke, "... Gerard van de Groenekan in 1968 ..."

... Yes, I still don't see the design as robust. ...

Me too.

I vaguely remember seeing some photos of one of these chairs where the joints were dovetailed rather than mitred. Might have been better, but still suspect until proven otherwise. I thought they may have been by George Nakashima; I googled, but found nothing.

[Bushmiller]

Looking a little further into the construction the bolts appear to go through the mitre joint and the back is either a dovetail joint or a box joint. The official (licenced) modern version made by the Italian Cassina company starts at A$2111 (plus a considerable amount of shipping, import duty and GST): The painted versions are more expensive! The reinforcing at the two mitre joints appear to be solid and they say there is no use made of bolts as with the Rietveld versions. perhaps the glues are sufficient. There are also unlicensed knock offs available, but I have not looked into that. One day I might be tempted to try building one.

Regards
Paul

[GraemeCook]

Looking a little further into the construction the bolts appear to go through the mitre joint and the back is either a dovetail joint or a box joint. ...

You are braver than me, Paul. I couldn't work out the construction details so I remained mute. The brass bolts seem to be visible on one surface, but recessed and bogged on the other. It seems that they are adding very little, if anything, to the engineering - providing a pivot line rather than bracing. But maybe I am just wrong!

I enlarged the photo of the joint:

Zig Zag Chair - detail.jpg


Please remember that this detail is from the van der Kroenekan chair made in 1968.

[Bushmiller]

I thought the knife maker(s) among you might be interested in this little vice.

Articulating Knife vise DIY - YouTube

Regards
Paul

[doug3030]

I thought the knife maker(s) among you might be interested in this little vice.

Articulating Knife vise DIY - YouTube

Thanks for that Paul.

I have seen quite a few knife vises similar to that before and they are all pretty good.

Because I have a vise like this on one of my benches ...

vise.jpg
... I just made an accessory similar to the inner pipe on that one in the video, which fits in the lower pipe jaws of this vise. It holds the knife similarly to the video one but the jaws made of timber. My vise provides all the same rotation options that the vise in the video provides but takes up less bench space.

If I was making a lot more knives I would probably consider making a dedicated knife vise, but I seem to make more plane blades than knives.

[Simplicity]

Sunday is hear again the end of the Week.(Nearly)

That means Sunday Night Jabber is yet once again.

All welcome, if your a member on this fine forum your welcome to join us.
It is a BYO gathering.

Tonight’s hot to trot subject matter(Not that we stick to it,but we do try)
Drum roll Please,


Will be quite a Boring one I’m afraid, please bring out the
Hole making equipment, the twist drills the brad points,those spade bits,the Forster ones extra.
Or anything else involved in making holes in timber.

Start Time 7.30 ish AEST this coming Sunday(12 June)

That means those in Melbourne, Victoria ,Australia Earth ,we start at 7,30 Pm ish time, for those who live elsewhere ,I’m sure you can work out what time to join us because I can’t due to my forum name.

The Get together is held using Skype,you are able to join in by just joining as a Guest.

Https://join.skype.com/u73k1kv4B1UL


See Ya 7.30 ish Matt

By the way Fresh Meat is most welcome to join in.


Sent from my iPad using Tapatalk Pro

[Pagie]

Do you mean round holes or square ones?

[Simplicity]

Do you mean round holes or square ones?

Round ones

[doug3030]

Last night I asked if anyone had any experience with Diamond sharpening disks for carbide circular saw blades and ideas for making a jig to use them.

I have since seen this one on Fleabay for the very reasonable price of $103.99 so I decided to open the wallet and free up some shed time since it was so cheap. I had seen similar things before for $300-ish. Not worth the hassles of experimenting to make my own at his price. Plenty of angle adjustment and will do any sized blade I can foresee ever owning. And free postage From Dandenong.

[Bushmiller]

Doug

That looks like a pretty good buy. You will have to let us know how it cuts the mustard (). I have taken some pix of my setup, which looks incredibly crude compared to that jig, and I will post them this evening for reference. The beauty of your purchase is that it is ready to go without any fussing.

Regards
Paul

[Bushmiller]

In response to Doug's enquiry about sharpening tungsten tipped circular saw blades here is the very rudimentary method I use. I started off only sharpening circular saw rip blades as the tooth is filed straight across. I use a drill in a clamp for mounting the drill on the bench. It can be swivelled. I already had a couple of these drill clamps from last century.

P1080272 (Medium).JPG

For sharpening tungsten carbide you require a diamond plate. I started off with the cup disc, but despite being the best quality of all my diamond discs, it is too bulky to reach into some gullets particularly where the gullet is small (not all circular saws are designed the same way) and where there are multiple teeth. You also need a means of securing the disc in the drill. I used bolts of the correct size for the disc and cut off the head. Nuts secure either side of the disc with one tightened hard against the plain shank.

P1080274 (Medium).JPGP1080276 (Medium).JPGP1080277 (Medium).JPG

The upper part of the clamp when mounted on the bench is tightened only enough to be firm and still allow a swivelling motion to bring the disc into contact with the tooth.

P1080278 (Medium).JPGP1080279 (Medium).JPG

Various boards were fastened together to bring the saw to the optimum height. The diamond cutting medium is quite narrow so this aspect is important. Holes are drilled in the timber to accept a locating dowel/tube/bolt suitable for the hole size of the particular blade. The trenches are there (made very roughly with a router) to allow the blade to sit flat as the tungsten teeth protrude either side of the plate.

P1080280 (Medium).JPGP1080282 (Medium).JPG

The blade and diamond disc are brought together

P1080285 (Medium).JPGP1080284 (Medium).JPG

For crosscut saws the blade needs to be tilted slightly to get a bevelled tooth. If the previous techniques are crude my solution to this takes crudity to full frontal as I simply place a washer under the blade to act as a spacer ( shown on top in the first pic and in the actual position in the third pic).

P1080286 (Medium).JPG P1080288.jpgP1080289 (Medium).JPG

The diamond surface needs to be cleaned frequently using this thing that looks like an eraser (I avoided calling it a rubber in case it offended our sensitive American cousin's ears should they be watching), but isn't. I don't know what it is called.

P1080290 (Medium).JPG

The diamond discs vary in size from 75mm to 120mm. I don't know the grit size. They were cheap from China years ago.

P1080291 (Medium).JPG

The teeth are sharp when they will take a shaving of a thumb nail (or any other finger that doesn't ruin your nail varnish ) as it is drawn across the tooth: Blade stationary, of course.

I hope this helps.

Regards
Paul

[doug3030]

For crosscut saws the blade needs to be tilted slightly to get a bevelled tooth. If the previous techniques are crude my solution to this takes crudity to full frontal as I simply place a washer under the blade to act as a spacer ( shown on top in the first pic and in the actual position in the third pic).

Thanks for sharing your ingenuity, Paul.

I love the washer under the blade. Aussie bush engineering at it's best.

[NeilS]

~

Doug

You may have more success with that design than I did.

I sharpen all the blades at my local men's shed and they need constant resharpening.

Bought a diamond CS blade sharpener of that design and I found the mechanical mechanism was too flimsy and flexible to hold a constant angle. It was also very difficult to adjust the pawl to remove just the required amount of carbide off each tooth. The best bit of the unit that I have is the diamond wheel and motor, so I thought about re-engineer the mechanism to get a workable sharpener out of it.

But after some fiddling about with it eventually gave up on it (your experience may be different) and upgraded to one of these...

370W Circular Saw Blade Sharpener | Forestwest Sharpener

... which has none of the flexing issue (it's made of heavy cast iron and very rigid), but still leaves a lot to be desired on its pawl arrangement, which I have been working on to improve. It is an excellent machine other than that and has re-sharpened 300mm dozens of times, so already paid for itself.

In retrospect I wish I had returned the first machine and gone straight to the second.

[NeilS]

370W Circular Saw Blade Sharpener | Forestwest Sharpener

... which has none of the flexing issue (it's made of heavy cast iron and very rigid), but still leaves a lot to be desired on its pawl arrangement.

BTW, I am interested in seeing any improvements that anyone has made to the pawl arrangement on the Forestwest style of sharpener. There is a thread on that CS blade sharpener over in the Sharpening forum if anyone has a contribution to make on that...

https://www.woodworkforums.com/f127/circular-blade-sharpener-timbecon-vs-forestwest-246102