Looking for tips on design/ prototypes

[pkinneb]

As my basement build rolls across the finish line I have started preparing for a couple upcoming projects one of which is making a couple of these bar stools by Marcos Amato.

https://www.instagram.com/stories/highlights/17879279431836753/

I reached out to see if he would be interested in selling me some plans but understandably he was not. So now I have to do it myself I think I have it pretty much figured out but looking for tips on determining sizing. I'm thinking I will use my sculpted bar stools for height and seat width at the front but other thoughts would be welcome as well. How would you determine size? How would you decide on thickness of things like the legs, foot rail, thin part of the seat etc? I plan on doing one out of poplar just to dial things in but any design construction tips would be helpful since I have never done this before. Thanks!

[Chestnut]

I bring pictures into a cad program and then scale the image off of a known dimension and use that to extrapolate the rest of the dimensions. It never comes out clean so i usually just round to the neareast what ever makes sense.

On those chairs they look more narrow. than something you'd typically see and I think that's part of the design. The other striking aspect is the delicate looking legs. my criticism of his piece is he used flat sawn wood for the legs and has a lot of grain run out. It'd look far far better with rift sawn legs and minimal grain runout. Not to mention will be stronger. I have some chairs that  have broken legs because of grain run out.

[RichardA]

I'd PM bmac, he's done some beautiful sculpting, he may have a valuable source for you, as well as plenty of his own experience to aid you.   I think "nut" is mostly right, rift or quarter sawn will give you more strength.

[Mark J]

I'd be concerned that such delicate back legs would be strong enough for real use without any bracing.  Do you know this design has seen day to day use elsewhere?

[wtnhighlander]

I'm with Drew on the grain orientation. In fact, I would not be surprised to discover some steel bracing concealed inside those legs. As for proportions, I agree with Drew there as well, but I would probably assume a standard height of about 24" for counter-height stools, 28-30" for true bar-height stools. Then I would use dividers to determine the ratio of each dimension against that established height to get a baseline.

[Chestnut]

37 minutes ago, Mark J said:

I'd be concerned that such delicate back legs would be strong enough for real use without any bracing.  Do you know this design has seen day to day use elsewhere?

I think most tend to over build furniture. I have some antique dining chairs that have 3/4" x 1 _ 1/8" legs, they are rift sawn mostly and have endured 100+ years and 3 generations of abuse. Poor grain selection, mainly having bad grain run out, makes wood seem a lot weaker than it really is. This is also based off experience trying to break down scraps to burn in my fire pit.

16 minutes ago, wtnhighlander said:

I would not be surprised to discover some steel bracing concealed inside those legs.

I actually would be. That'd be not only difficult but probably expensive. I wouldn't have any issue with legs that size with proper grain selection. I'd even have no issues tipping it back on 2 legs. Joinery is more likely to fail than braking a leg.

[Coop]

I don’t see any pics, darn it! 

Is it the barba negra  stool? 

[Chet]

3 minutes ago, Coop said:

I don’t see any pics

I also don't see them.

[pkinneb]

3 minutes ago, Coop said:

I don’t see any pics, darn it! 

Is it the barba negra  stool? 

That's weird they show up on mine.Yes it is

[Coop]

Just now, pkinneb said:

That's weird they show up on mine.Yes it is

I googled him and saw the grain runout that nut mentioned is the reason for the guess. 

[pkinneb]

1 hour ago, Mark J said:

I'd be concerned that such delicate back legs would be strong enough for real use without any bracing.  Do you know this design has seen day to day use elsewhere?

I don't but they would not be for daily use. I thought I would make two for when we are playing darts just something a little more compact.

[Coop]

Paul, with the quality of your work and as Rick mentioned, a little input from chair king @Bmac, Mr. Amato will be calling you for a set of your plans! 

[Bmac]

Very interesting design, but it does look surprisingly simple. I think you can easily figure this out without plans. I wouldn't worry too much about stool hieght, height will be determined by counter height. Typical counter height of 35-37" calls for stool height around 24-26", bar height of 40-42" calls for stool height 29-31".

Grain orientation should be carefully considered for the legs, but if you have good grain orientation I think you will be fine. I would consider adding strechers, esp if you are going with the higher stool height. I don't think it will detract from the design too much and it could be your take on the design.

Couple things I see about the design which you have probably already figured out are;

Leg stretcher construction is glued and held togther with dowels or dominos. Making the top of that leg stretcher piece flat could be done on the table saw once you determine your angle.You'll need to figure out the splay angle from front to back, but I see no splay of the legs out laterally. That look is accomplished with sculpting. 

Key to this is to make your legs square and don't reduce until you has any lower stretcher joint areas figured out. You also will likely need to keep legs square on 2 surfaces to cut a nice flat top too the leg/stretcher piece (fence side and table side). There are ways possibly where you could leave part of the leg square, the part that sits against your sled and table. Bulk of shaping of legs should be done on bandsaw. 

Those legs get pretty delicate, at most 1" diameter at bottom, but that should be fine. 

Not sure if any of this is real helpful, but those are a few of my observations.

[pkinneb]

10 hours ago, Bmac said:

Very interesting design, but it does look surprisingly simple. I think you can easily figure this out without plans. I wouldn't worry too much about stool hieght, height will be determined by counter height. Typical counter height of 35-37" calls for stool height around 24-26", bar height of 40-42" calls for stool height 29-31".

Grain orientation should be carefully considered for the legs, but if you have good grain orientation I think you will be fine. I would consider adding strechers, esp if you are going with the higher stool height. I don't think it will detract from the design too much and it could be your take on the design.

Couple things I see about the design which you have probably already figured out are;

Leg stretcher construction is glued and held togther with dowels or dominos. Making the top of that leg stretcher piece flat could be done on the table saw once you determine your angle.You'll need to figure out the splay angle from front to back, but I see no splay of the legs out laterally. That look is accomplished with sculpting. 

Key to this is to make your legs square and don't reduce until you has any lower stretcher joint areas figured out. You also will likely need to keep legs square on 2 surfaces to cut a nice flat top too the leg/stretcher piece (fence side and table side). There are ways possibly where you could leave part of the leg square, the part that sits against your sled and table. Bulk of shaping of legs should be done on bandsaw. 

Those legs get pretty delicate, at most 1" diameter at bottom, but that should be fine. 

Not sure if any of this is real helpful, but those are a few of my observations.

Thanks!! This is very helpful.