new dovetail jig idea

[neilyweely]

OK - I am going to post this and go to the 'shop to try and make it work, so maybe in half an hour I will be back explaining how daft I am!!

Bearing in mind my incompetence I often try to cut dovetails on the bandsaw to no avail. They are always far better with the router and jig, or the chisel and small saw.

So, driving home I got to thinking, what about a new sort of jig for the bandsaw, that cuts dovetails. I thought all the cuts are straight cuts, ie no curves, so it should be feesable. How about some sort of chock, cut at the correct angle, to sit under the wood and hold it at correct angle (8') whilst it is passed thru the bandsaw. I am not good with the laptop, or camera, so am relying on your imagination here!! So, cutting the male part is easy enough on a bandsaw, and using a specially cut chock of wood, maybe sliding on some sort of housing unit, so should the female part be.

Of course this will still require some skill (which probly rules me out), but God only knows I need some help with my DT's as the kitchen we want making looks like taking a year or so to make!!!

What I am hoping is that this will spark off the imagination of someone with more talent than I, and we can come up with something between us all!!!

So, I will be back later, with a red face and a few less strands of hair on my head, and let you know where I failed!!!!

Any help will be greatly appreciated. Thanks a lot for your time.

Neil

 

[Mr Ed]

I'm guessing you've not read David Charlesworths 'Furniture Making Techniques - Volume One', as it contains what I think you are describing.

If it is, he seems to be able to get excellent results from it so is definitely worth giving it a go.

Cheers, Ed

 

[mailee]

I am sure Steve Maskery did something along those lines a little while ago. If my memory serves me right it was published in GW. There again the grey cells aren't what they used to be. :?

 

[Woodwould]

I presume you're talking about a pair of start-to-finish jigs and not simply an 'aid' that helps you cut out pre-marked dovetails.

If that's the case, then I would look at making a pair of sleds that run in a T-slot. If your bandsaw table doesn't have a T-slot, you may need to make a complete sub base that does incorporate one. Although, on a more basic level, you could use a G-clamp to lock the slider in the mitre guide track.

To cut the dovetails, how about a sled with an 8° fence that in turn runs on a guide in a track in a sub base at 90° to the mitre track/T-slot. You could easily incorporate a stop for the base line cut. Advancing cuts could be dictated by strips of wood equal to the dovetail width being added (or subtracted) to the fence as the dovetails progress.

The pins could be similarly cut on an 8° sloping sled or the table could be tilted to the same angle and a flat sled used. 'Advancement strips' could be added as before.

I haven't bothered with a dovetail jig in the past as I can mark and cut dovetails pretty quickly and accurately by hand or on the bandsaw. However, I don't really enjoy extreme repetitive work, so a jig could be attractive if there are lots of drawers to dovetail.

 

[neilyweely]

OK - Ed, not read it, will do now.

Mailee - HOw are you mate, I had a look at GW today, along with some others, boy, ain't they expensive!!! Is there any way of getting to that article on line? Thanks either way bud.

And Wouldwood - I believe you and I are talking about the same thing, or thereabouts. I will try to sketchup something to show y'all, although you will have to bear with me as I am not all that with, well with my brain!! (I can't seem to get on with Sketchup). I think I follow what you are describing, and it is certainly along the lines of what I have tried to make. I am using an old startrite BS, although for small work I use another BS which is a smaller Sealey 2 wheeler. It saves swapping blades over all the time!! They both have t-track, so I am ok there.
Wouldwoodwould you do me the courtesy of showing me what you mean visually, if you are able, as I would like to get this right, and 2 heads are better than one!! (Think I deserve it for that pun) :lol: :lol:

On the subject of bandsaws, and at the risk of going off at a tangent, can anyone reccommend a fence for my startrite bandit as the one I have is useless. What is the smaller Axminster BS fence like?? The big one is too big.

I should add that the reason I am trying to suss this out is my DT jig fell to pieces this evening (clamp pushed top of bolt off!!) so I could really do with a degree of success here!!!

Thanks folks. Goodnight.

Neil

 

[Woodwould]

I don't have any photos or drawings of what I have in mind, but let's examine the two sleds a little closer.

The Dovetail Sled.
The Dovetail Sled would consist of two separate tables that slide at 90° to each other. The Dovetail Sled would probably only be able to cope with a range of dovetail widths to suit 75mm-125mm drawers (I haven't tried this, so I'm only guessing). You'd probably require a second sled for larger drawers etc.

The base table would require a T-strip screwed to its underside so it slides parallel with the blade in the bandsaw table's T-slot. This action would obviously provide the depth of cut to the bottom of the tails. A threaded adjustable stop could be attached to the underside of the sled to stop against the front of the table or fence rail.

On the top face of the sled, you'd need another T-slot at 90° to the one beneath. The top table (with a similar T-strip screwed to its underside) would slide in the base table's T-slot at right angles to the blade which would provide the horizontal adjustment for cutting the individual tails.

A fence would need to be attached to the top table at 8° to the blade (or which ever angle is preferred) to provide the angle cut to the tails. The piece of wood being cut would have to be flipped over to cut the corresponding cuts on the opposite side of each tail.

Wooden spacers equal to the width of each dovetail could be incrementally stacked against the angled fence with each cut, thereby making accurate and repeatable dovetails.
A lever clamp screwed to the top of the top table would lock the piece being cut into place for each cut.

The Pin Sled.
The Pin Sled needs only be a single table affair, but with a sloping top to match the angle of the dovetails cut on the Dovetail Sled. A similar stop arrangement would limit the depth of cut and a similar arrangement of incremental spacers could be used, although their width would differ from those used for spacing the dovetails due to the angle involved with the Pin Sled. Again, a lever clamp could be employed to lock the workpiece in place for each cut.

That's the basics that are flying around my cranial cavity and there are already some tuning aspects popping up, but that should be enough to get you started.

I quite like the sound of this now, so if you make a go of the jigs I think I'll build one myself!

 

[OPJ]

Neil, you could try sending Steve a message of e-mail. It he still has the old article on his PC then he may be able to help. :wink:

Don't worry, Alan, there's nothing wrong with your grey cells - I remember seeing it in the magazine a couple of years ago too.

 

[Steve Maskery]

My article is a development of an idea which I first saw in Mark Duginski's The Bandsaw Book.

The workpiece is presented to the blade at an angle and spacer blocks are used to set the pitch of the dovetails. Variable spacing and even unsymmetrical spacings (when making drawer sides, for example) are possible - you just have to be systematic and keep track of which spacers go where.

It's an excellent method, it does through dovetails quickly and if you want half-blind dovetails you can cut the DTs this way and then do the pin board by hand, it will still save you hours.

There are a couple of limiting factors and pitfalls. First, you need the narrowest blade you can get. I use a 1/8" blade, but MD talks about using a 1/16" blade - I've never found one. Secondly, there is a practical limit to the width of board you can do. This is great for drawers, but anything over, say 300mm is going to be difficult or impossible, especially on a small bandsaw.

Thirdly, you have to have your machine set up very well indeed. If you make the jig to 8 deg but you have 5 deg of drift, your joints will actually be 3 or 13 deg - not what you want at all.

Finally, the pins cannot be finer than the bandsaw blade, so you can't do the jewellery-box pins which are just a saw kerf apart. You have to be able to ket the blade in sideways. MD recommends nibbling away with the blade to widen the kerf until you can get in sideways, but I find it easier to cut the access slot on the tablesaw with a special guarded jig. Similarly I have a ramped jig for cutting the pins, where MD suggests just lifting the workpiece. Mine is much better supported.

This joint was cut this way

I urge you to try it. Once you have it in your head it really is very straightforward, and the results are excellent, especially for batch work.

I do have plans to film this actually, but haven't yet got round to it, I have other things on the go (like filing my increasing large collection of "Thank you for you interest in....unfortunately on this occasion...we regret...we wish you well with your career..." letters). Maybe one day.

PM me if you want more.
S

 

[Benchwayze]

Duginski's book was where I first saw this idea. I don't know what happened to the book. Maybe I loaned it someone, but it's gone!

The procedure is set down in the DC book too. I think though, the more expensive the bandsaw, the better the results will be.

FWIW I cut my tenons on the bandsaw. It seems such an accurate way of producing them and I'm not stooping over the vice either!

 

[ByronBlack]

does it actually need inventing? There are many dovetail jigs already out there that do a fine job - I personally like the look of the gifkins jig that you use on a router-table, looks to do the job accurately and quickly.