Tolerances

Ask your questions here. Guests welcome to post!
Post Reply
goanywhere
Posts: 374
Joined: Wed Mar 30, 2011 7:20 am
Type of boat I like: Fishing SOTs.
Location: Adelaide, South Australia.

Tolerances

Post by goanywhere » Thu Aug 11, 2011 1:49 am

Hi, just a question about the required tolerance of components. I have started cutting out panels and pieces for the Sabalo, and I am achieving roughly 1-2mm accuracy against the plan measurements. This isn't the QA measurements, this is the dimensions such as width of panels. What is considered the acceptable tolerance of individual components? I think I have read somewhere on this forum that +- 4mm is ok, but that seems a bit high to me.
My psychologist reckons I need lots of fishin' therapy!

User avatar
jem
Site Admin
Posts: 4864
Joined: Fri Jun 18, 2004 8:14 pm
Type of boat I like: Wooden
Location: Greensboro, NC
Contact:

Re: Tolerances

Post by jem » Thu Aug 11, 2011 5:54 am

Of course you want to be as precise as possible but one could go up 6mm in some cases. There isn't an exact number.
-Matt. Designer.

goanywhere
Posts: 374
Joined: Wed Mar 30, 2011 7:20 am
Type of boat I like: Fishing SOTs.
Location: Adelaide, South Australia.

Re: Tolerances

Post by goanywhere » Thu Aug 11, 2011 9:05 am

That's nice to know, just in case.... but so far so good. All within 1-2mm so far.

Also, I used a new coping saw to cut out the CP floor panel tonight. It is brand new and really sharp so it cut through the sheet like a knife through butter, but after awhile it started to grab and was really hard to saw. What can be done about that? Can candle wax be used on the saw when cutting? (a trick they taught us at school way back when...) I would prefer to use this saw when cutting straight edge panels.
My psychologist reckons I need lots of fishin' therapy!

User avatar
jem
Site Admin
Posts: 4864
Joined: Fri Jun 18, 2004 8:14 pm
Type of boat I like: Wooden
Location: Greensboro, NC
Contact:

Re: Tolerances

Post by jem » Thu Aug 11, 2011 10:13 am

the wax might help but it sounds like the blade got dull. But that sounds wrong if it's a new blade. Shouldn't dull that quick.
-Matt. Designer.

goanywhere
Posts: 374
Joined: Wed Mar 30, 2011 7:20 am
Type of boat I like: Fishing SOTs.
Location: Adelaide, South Australia.

Re: Tolerances

Post by goanywhere » Thu Aug 11, 2011 6:18 pm

No, the blade isn't dull. I might try rubbing some candle wax on the blade and see if it helps. It might be a bit of resin from the ply sticking to the blade.
My psychologist reckons I need lots of fishin' therapy!

Bemm 52
Posts: 309
Joined: Wed Feb 13, 2008 3:57 pm
Type of boat I like: <-- Please read instructions to the left and delete this text. Then, tell us what type boat you like! :-)
Location: Sydney Aust

Re: Tolerances

Post by Bemm 52 » Sat Aug 13, 2011 2:23 am

Try a few experimental cuts with a circular saw with the blade set to just cut the ply .....it is quick and with a bit of practice accurate and some quiet tight radius's can be achieved..............as far as accuracy is concerned I cut proud of layout line then use a sanding block or a block plane to get to line
Enjoy the build
Cheers Paul

goanywhere
Posts: 374
Joined: Wed Mar 30, 2011 7:20 am
Type of boat I like: Fishing SOTs.
Location: Adelaide, South Australia.

Re: Tolerances

Post by goanywhere » Sat Aug 13, 2011 5:23 pm

Actually, I have discovered that the new saw I bought which I wrongly was calling a coping saw, but actually is a veneer saw, is the best tool I've used yet for cutting ply. It has a very thin blade, and not much offset on the saw teeth, just enough to cut a clearance for the blade. It also has a rounded saw on the top front edge for cutting through from the top (easy to cut hatches). It seems to have a lot of features of a Japanese pull saw, but is more conventional in design and is a 'push' saw.

It works like a dream for long, straight cuts, but has just enough flexibility for long sweeping curve cuts as well. It has saved me heaps of time cutting and sanding, and has a satisfying feel to it as it slices through the ply. I don't have to allow for blade drift or curvy lines, as it cuts dead on the centre of the line. All you need to do is give the edges of the cuts a quick sand to get the little splintery bits off and you're done.

I solved the only problem I had, which was the blade grabbing. I just needed to support the loose side of the cut to stop it hanging down and it pretty well stopped it. I do rub just a little candle wax on the blade every now and then to keep the blade lubed, and she's right as rain!

This week I have measured and cut all of sheet 3 and 4, and measured sheet 1. (I wanted to test out the saw on a variety of shapes to see how it performed, that's why I went to sheet 4).

I'll post a pic of the saw later today.
My psychologist reckons I need lots of fishin' therapy!

goanywhere
Posts: 374
Joined: Wed Mar 30, 2011 7:20 am
Type of boat I like: Fishing SOTs.
Location: Adelaide, South Australia.

Re: Tolerances

Post by goanywhere » Sun Aug 14, 2011 9:08 am

This is the saw I was talking about.

Image
My psychologist reckons I need lots of fishin' therapy!

john the pom
Posts: 192
Joined: Mon Nov 12, 2007 8:12 am
Type of boat I like: <-- Please read instructions to the left and delete this text. Then, tell us what type boat you like! :-)
Location: S.E. Queensland

Re: Tolerances

Post by john the pom » Mon Aug 15, 2011 7:28 am

Someone else may know better but I would think wax is probly not a good thing to contaminate your wood with. Then there is the wax on your hands touching other parts than the edges the saw touched.
Wax is like thick oil. Yous're gonna have to clean up well before applying epoxy I reckon.
cheers John.

goanywhere
Posts: 374
Joined: Wed Mar 30, 2011 7:20 am
Type of boat I like: Fishing SOTs.
Location: Adelaide, South Australia.

Re: Tolerances

Post by goanywhere » Mon Aug 15, 2011 9:28 pm

Only a very light rub. And I sand the edges after cutting. I doubt that there is enough to worry about. It's not like oil, which soaks in and would be a problem.
My psychologist reckons I need lots of fishin' therapy!

Post Reply