Ian while I can't help with your query I'm sure one of the forum members with experience in this area will be along to help.

 

How thick is the stock that you are planning on cutting? The scroll saw that you have will only cut wood about 1" thick or less. You will probably need to use a band saw with a small blade to make this piece.

I once made a self closing gate by making a cylinder of maple wood with a 20 degree diagonal cut through the center. The lower half of this cylinder was attached to the hinge so that it couldn't turn and the upper half of the cylinder was attached to the gate. Opening the gate made it rise up on the hinge pins due to the ramp cuts of the cylinder. When the gate was released, gravity returned the gate to it's closed position. This was an indoor gate and not subject to the wear and tear of the elements, and my self closing feature only survived about 6 months.

How about using the early colonial method to close the gate. They used a post located behind the fence at the hinge end of the gate by about the width of the gate. They attached a chain between this post and the non hinged end of the gate long enough to allow the gate to be opened to about 90 deg. At the center of this chain they attached a weight (usually a small 3-4" 2-3 pound cannonball When the gate was opened the tightening of the chain would raise this weight and when the gate was let go, the weight on the chain would fall and pull the gate closed. The beauty of this is that it is nearly weather proof.

Charley

 

Charley, thank you for your encouraging and informative posting. Today I spent too long making a Coping Saw Spiral; blade it into the Grizzly scroll saw I have borrowed. As ever I was called for the evening meal just when I was about to begin testing! I did present a small section of timber to the blade and it seemed to gnaw it. No chance of cutting the wood. Unless the blade is in upside down, if that would make a difference. I have super-glued some 'ends' on to hair-like spiral 5" blades but I think they are now too short to fit the Grizzly.
I have a medium sized bandsaw and I have found a 1/8th inch blade (new) - so perhaps this may produce a spiral. I read that you need a spiral bandsaw blade, but this would cut-up the rubber 'tyres' on the wheels of the saw..more attempts tomorrow.
(I am hoping to make this 3" dia spiral about 20 degrees like yourself and when I have cleaned the two parts up, I want to use them as patterns and cast them in pewter, which should last a bit longer than oak).
I did think of using lignum vitae bowling green bowls on the end of a chain to close the gates, as we are fresh out of cannon balls - but I would rather use them on the grass (if I could get my hands on some).
I hope to keep in touch.
Regards, Ian

 

Ian, a spiral scroll saw blade just has tips all around it to make it easier when changing direction. It isn't the best for very fine work. A spiral blade doesn't actually cut spirals. In this case I would make normal hinges and use a pulley system with weights to close the gates.

Good luck Jeff

 

Thank you Jeff for yourGood Luck and posting. I understand your point, but so far, I have only found examples of spirals being cut with a spiral scroll saw blade. Although I have made all sorts of furniture and woodturned professionally too, I have never had occasion to use a scroll saw - so I am very pleased to have advice. My experience of scrolling is watching "U Tube"!! Still prepared to learn (84).
I 'rearranged' the holding the blade bits on the Grizzly this morning and inserted a normal Coping Saw blade, - but now I know scroll saws don't like such heavy duty blades. It wanted to bounce the wood up and down!
This afternoon I think I will insert an 1/8" bandsaw blade (in the bandsaw!!) and attempt a spiral, but I think it will 'jam' or snap the blade. (Watch this space!)
Regards

 

An 1/8" bandsaw blade will allow you to cut curves as tight as about 1/4" diameter without binding and breaking the blade. For the size of your gate I can't comprehend that the tightest curve of your spiral would need to be that small.

When you put the coping blade in the scroll saw, did you put it in with the teeth pointing down? If it was installed with the teeth pointing up you would certainly have problems with the board jumping as you tried to cut it, but a blade installed teeth down will also on occasion have the board jump slightly if you are making a very tight curve and the sides of the blade are binding in the cut.

Charley

 

Yes, as I feared, the 1/8" band saw blade snapped on me starting to try to cut a spiral in a2.5" diameter cylinder of elm. I suspect there are hidden and included angles in the development off a 3D spiral which I do not understand and that must be why a guy on U Tube successfully uses a spiral scroll saw blade, (which my borrowed 16" Grizzly does not accept).
I hardly dare disclose what my last throw to produce a spiral will be later tomorrow, but I will! I have superglued the ends of four flat ended spiral scroll saw blades, in a bundle, all facing the same direction. I glued them together at each end and for a quarter of an inch. I then made two short pieces of 3/16" aluminium rod, (ex knitting needles), about 1/4" long and drilled a 2 mm hole through each. I countersunk one side of the through hole and then stuffed each end of the 'bunch of blades' into the hole, counterunk on the outside and suitably prepared with a 5 minute epoxy resin, (beginning with A). My pins!
I have tried to make a tough spiral-type saw WITH pins. I imagine the pins will not be able to stand the pulling pressure and come off as soon as some wood is presented to the saw blade. I will put the teeth facing downwards, as I did with the coping saw blade which gave trouble! I think I will end up having to commission someone to make small spirals for my project!
Thank you continuing to help me..
Ian

 

But, from designes I've seen of antiquity pieces that would do that are basically... you create a piece that will be the pin socket and the guide as one tublar piece... then cut diagonally across it at an angle.

You use half of it as your socket, which is locked to the mounted structure. The other half is locked to the pin of the hinge. So when the door swings open, it raises on the diagonal. When let go, the weight pushes it along the diagonal to where it fits together (in it's original setting, which is it's lowest position).

Did that description make sense to you? That is old-school antiquity engineering, using just gravity to self-close. Fairly simple design and will work for years on end. I don't remember exactly where I saw those fittings... but I'm thinking it was on old-west styled (mid-1800's) swinging Saloon Doors... And on Victorian period swinging kitchen doors.

 

They still make Saloon door hinges, but they are a bit small for a gate. Here is an example. Notice the ramps, much like my suggestion about a cylinder with a diagonal cut. They aren't spirals, just ramps.

Charley

http://www.amazon.com/Stanley-Hardw...dp/B00004Z0YY/ref=sr_1_1?ie=UTF8&qid=1411731654&sr=8-1&keywords=cafe+door+hinge

 

Exactly-- But, he is making the hinges, so could make them in a larger scale. I've seen that same design in larger scale used on heavy wrought iron garden gates. I guess the question would be is where the weight would overcome the friction (that would prevent it from closing).

 

Thank you Mike for the swing door hinges idea. I have looked and looked at the bits which go to make up the package - and I do not understand how they go together - but it sounds as though they would not be appropriate for 4" x 3" oak edges to the gates. I could not fit them anyway as the gates are hung already.
I just need 'something' to fit between the bottom of the pins, and the oak top of the hinge. I haven't had the opportunity to try to cut a spiral toay, (which I will do over the weekend with my 'constructed spiral scroll saw with pins??). When that fails, I will return to my very dirst idea about six weeks ago which I disgarded, slicing across a cylinger of wood, instead of pursuing the spiral.

Charley, you described absolutely the same solution on the 23rd Sept. I will do that if the spiral fails (again).
Thank you all for your great interest and experience. I have to learn how to attach a pic.
Ian

 

I have looked and looked at the bits which go to make up the package - and I do not understand how they go together - ...

How the pieces fit together:

But (yes) you say already that you have hinges made already and the gates hung, right?

 

Posting a picture is easy. At the bottom of the box where you type in your reply, click on the "go advanced" button and then click on "manage attachments". It will then open a small pop-up type window. You can choose up to 10 files on your computer by adding them one at a time to this window. When you have chosen all of your pictures, click on the "Upload" button and it will upload and attach them to your reply.

Charley

 

I have noted the saloon door hinges and they really do not apply to 'my' gate
The difficult to understand idea presented by MAFoElffen is favourite and I think is on the same lines as Charley's ideas mentioned in an earlier post.
I have now tried unsuccessfully with a bundle of 4 flat ended spiral blades, whose ends (only) I super-glued and then epoxy-resin'd into aluminium pins I made from aluminium knitting needles. Looked good, one pin came off as I put it into the Grizzly!
I have also been unsuccessful with a so-called spiral file with pins, (from US) which turned out to be rectangular in section. not round - and would not cut a controlled spiral in a 2.5" cylinder of expanded polystyrene - which I am reduced to trying! I could cast the units in pewter (90% tin) if I could make a pattern in ANY material. I am going to have to find a saw I can borrow which will take saw blades without pins !
(Or a star who will cut one for me!!)

 

Sorry-- I'm 2D and 3D visual.

If you made 3 more posts somewhere here. Then you could upload a sketch or picture... and we could all see what you are trying to do. Lots easier to make a recommendation based on a common understanding of what you are working with and trying to do, right?

 

I guess from what i'm reading, & seeing from your post, I don't see where a spiral blade is going to benefit you. A spiral blade cuts both directions in the scroll saw. It doesn't cut spirals, my friend. It has its place, more for widening, and places where another type blade won't do the job. You can use a spiral blade for most any type cutting of a pattern, I suppose, but, the edges will be rough and sometimes jagged, depending on the material & blade speed, and need sanding. You can go to wooden teddy bear & get yourself a few blades, or other places online, but like I said, unless I'm really confused, I just don't think a spiral blade is the answer.

 

I know what you mean - a spiral on a cylinder is a straight line (imagine wrapping a sheet of paper around the cylinder at an angle) so why would you need a spiral blade? But if I'm envisaging this correctly, I think the reason is that you'd need to cut the line in both directions at once. You'd be rotating the cylinder against the blade, so the cylinder is moving forwards into the blade the top and, simultaneously, backwards at the bottom (or vice versa). Hard to say for sure without seeing the youtube video.

Possibly an alternative way of approaching this problem might be to adapt techniques used for turning screw threads or spiral spindles.

 

Thank you Bulldog65, but as a novice scroll saw user, I have tried to research how I might cut a spiral up a cylinder to develop a gravity fed gate closer. The only successful method I have seen is on U Tube, where a smart guy cuts an excellent spiral up a relatively small diameter cylinder - using a spiral scroll saw blade. I have tried unsuccessfully to cut a spiral using a scroll saw which will only take T or peg-ended blades - and spiral blades can only be bought as flat ended blades. I have also broken a 1/8" bandsaw blade trying this. Please tell me Bulldog, how I will cut a spiral up a 2.5" cylinder, without a spiral blade. I would really value your advice.
I am thinking I may have to go on to Design No 2!! (or plan B)

 

That's just what i was kickin' around too, Mr. Andy. It would appear to me that it would be easier, & more feasible to cut the spiral using the lathe. Yes, Ian is up against the fact that what he is wanting to cut, or attempt to cut with a spiral blade is small & maybe fragile, but I still think it would be a cleaner cut with a lathe tool of sorts on the lathe. And without seeing this video, I'm trying to picture getting this done the most efficient way. I've been scrolling a number of years, & haven't run up against something like what Ian is describing. If the cylinder is 2.5", it would be plenty stout enough to stand the pressure of a threading tool to cut a fine spiral on the lathe, I would think. I have been wrong before, but it's a thought.

 

Let's try rethinkin' this from a country boys' angle. If Ians' using the spiral blade in the scroll saw to cut his spiral for a given depth, or width, per say, to move the stock against the blade is still going to give you a cut in one place. Straight up & down, correct? Ok, so, you're going to have to rotate that stock to get the spiral. In turn, he stated he's using 2.5" stock. Wouldn't it be more feasible to put the stock in the lathe, using, say a spindle gouge, or small parting tool, & low speed, to cut his spiral that way? It would appear to me that would be more efficient than using a scroll saw. I don't mean to be a pain, but, I still don't think the spiral blade & scroll saw is the answer. And having the issues he is with blades, wouldn't the lathe be the better alternative? Like you, Andy, not seeing this video, it's hard to judge, & without any other pictures of what Ian is trying to do, I think the lathe would be worth a try.

 

Here are some videos showing how spirals are cut using a scroll saw (and you do need a spiral blade.

Scroll Saw Helix Forms - YouTube

Scroll Saw Helix Jig. - YouTube

Spirals By Steve

That said, I don't understand why a spiral is needed for a self closing hinge unless the door, or gate. All that's needed is an inclined surface as already described. One side fixed to the gate side of the hinge and the other to the jamb side. A spiral might be more elegant but I think it would also be weaker.

 

well, truthfully, after watching those videos, they don't appear to be nothing more than a couple of fellas with nothin' but time on their hands, and making fancy cuts for looks. And that's fine. And true, they do use a spiral blade in the saw, but, I don't see what any part of the spirals being cut are going to benefit Ian in any way. And I am in full agreement with you RJM, I believe it will be weak in many ways. And will not last long. I also agree that the incline on one side would be the way to go. I've kicked this around for two days, & I am not able to come with an answer to his issue.

 

I've made my own spiral blades by clamping one end in a vice and twisting the other.