Thread: Cutting dovetails to cut dovetails

They look good Derek - alas no suggestions.

A couple of suggestions:

1) Instead of using a normal hacksaw for cutting small pieces of brass by hand I've found using a minihacksaw gives a bit more control and produces around half the kerf of a regular hacksaw. I would also attempt the initial cut to the desired angle (instead of a square cut) with the mini.
2) Then I would make a jig to hold the pieces right way up, square in 2 dimensions and at the correct angle in the other while applying them to the sander - if you make the jig adjustable you could use it for a range of angles. That way you can get see how close you are to the desired marking.
3) Once you are close I would also consider switching to a sanding disc using very fine paper - that way you can work in a more controlled manner and creep almost up to or also right to the desired requirement. When I do my brass stuff I use new 320 grit or an old 240 grit to do this.
4) Do you also mark the insides of the brass angle? I find this is useful when filing since it reduces the number of times you have to check measurements with calipers and bevels

Very impressive Derek. I have only thought of buying these. Where is the hinged gauge from by the way? I don't want to hear that you made it, although I wouldn't be surprised!

I may have misunderstood your question, so just to clarify things, are you working on the dovetail angle and then the right angled side, or vice versa. I imagine that it would be easier to get the dovetailed side sorted first and then sand or file the right angled side to suit.

In awe

James

Thanks James.

No, I did not make that saddle gauge. It comes from Bridge City Tools. However, I did make this one:





.. and this one ..



It is my little joke (a dovetailed dovetail marker). Ratio is 1:7

Here it is with the BC saddle for a better look at the latter ..



Regards from Perth

Derek

Yours has more soul though.
John

I wonder whether the production difficulty could be reduced if the "square " element were square all the way round and the angled element only started from the surface of the wood. That is how your dovetailed dovetail gauge is set up.

This would separate the two elements so that adjusting one would only require a minor adjustment of the other which would be parallel to an existing line.

Derek,

I can undersand your decision to make a only a limited edition of your home-made dovetail markers, when Lee Valley sell a set of two for $10.50 ($20 from Carbatec). But I imagine yours will be collectors' items in the future

I have the Lee Valley set and find they work beautifully.

Rocker

I wonder whether the production difficulty could be reduced if the "square " element were square all the way round and the angled element only started from the surface of the wood. That is how your dovetailed dovetail gauge is set up.

Hi Jeremy

This is how I do it. The problem will occur if the dovetail angle is filed incorrectly, even by a fraction of a degree. This then send you back to reshape the square as well. So you can go back-and-forth! Pass me the whisky!

It comes down to filing skills.

I will make more in the future.

Hi Rocker

Thanks for the kind works. These tools are rarely just about whether they work. They are also about the pleasure in using something that looks good and feels good in the hand.... otherwise we would not be the tool junkies that we are! I hope that you are well.

Regards from Perth

Derek

Another thought Derek. I haven't tried it but it might work.

Why not make some "perfect" square and dovetailed angles that fit around a Magsquare

or the magnetic base for a dial indicator to use as fences.

Make them out of mild steel angle so that they fit exactly around the edge of the switch or base. Set it at the correct height for the surface that you want to file or sand , and turn on the magnet to hold the steel.

When the rough work on the brass is almost finished, push the brass up against the steel fence and run it against the sandpaper (with the switch or base running on the glass or whatever that the sandpaper is stuck to). When the base or switch is running flush with the glass, the brass should have the correct angle.

Originally Posted by derekcohen

This is how I do it. The problem will occur if the dovetail angle is filed incorrectly, even by a fraction of a degree. This then send you back to reshape the square as well. So you can go back-and-forth! Pass me the whisky!

It comes down to filing skills.

I will make more in the future

Derek

Hi Derek,

I think they look pretty slick as they are. (nice work)

However, I see your problem, I have made these from **thin** aluminium angle in the past. The material thickness exacerbates the problem.
I realise this post is now getting pretty old, and you have probably finished the first batch

If you are doing a second batch I would set up a jig (need one for each ratio) and grind to correct angle on the disk sander, at that point you have a plane intersecting with the brass angle, so the "square" section of the brass will be at an angle to the marking surface, you need to file/linish this to be at right angles to the marking surface without touching the bottom edge. I would stay away from the disk sander for this step and instead use a sanding block with 220 to square it up without disturbing the lower edge. The transition point at the apex of the angle could be smoothed if you want.

I suspect that this is probably close to what you are already doing...

If you want to do a chemical etch of a logo or something, you can use
electronic pcb photo-resists and ferric chloride.

I reckon you could use a table saw to cut the brass hunk so it becomes brass angle and a small square rod... Get what I mean?

What about making the markers out of flat section. This I suspect would make it easy to keep things at the correct angles then working in 3D from the start.

One finished, cut a v shaped grove (not all the way through) in the flat at the point of bending and bend.

Then solder it all into place.

Just an idea.

Originally Posted by thumbsucker

What about making the markers out of flat section. This I suspect would make it easy to keep things at the correct angles then working in 3D from the start.

One finished, cut a v shaped grove (not all the way through) in the flat at the point of bending and bend.

Then solder it all into place.

Just an idea.

Or, instead of soldering, you could dovetail it like a Speirs or Norris plane - as described in Jim Kingshott's book or on Peter McBride's website. Then you could perpetuate the joke of the dovetail marker being itself dovetailed!

For contrast, you could make one side brass and the other steel.

If you did, you could make a jig to hold the two pieces square and tight while you peen the dovetails - like the shoulder plane shown in ShopNotes a couple of years ago - if you don't have a copy of the article PM me and I will send it to you in a day or so.

Originally Posted by jmk89

Or, instead of soldering, you could dovetail it like a Speirs or Norris plane - as described in Jim Kingshott's book or on Peter McBride's website. Then you could perpetuate the joke of the dovetail marker being itself dovetailed!

Thought of that but I have no idea about doing dovetails in brass let alone timber. I might try it though after seeing Mr Mcbrides site..