Should I bother with a fuselage jig ......

[Rich Griff]

Jig a jig, b side to albatros.

 

Remember if the jig is "out", so is everything made on it.

 

The red Square sticker is available elsewhere. I accurately drew mine onto the flat, square ( twas oblong really ) level and warp free jig board some years ago now.

 

The slec captive nuts are fitted underneath, so are just slightly recessed on the top.

 

Feet glued underneath the board accommodate any protrusion of captive nuts and/or screws.....

 

Cling film these days prevents glue/airfrane adhesion issues.

 

I used to used greaseproof paper with plan info drawn onto it, placed on a board, but jig and cling film is much quicker and less hassle.

 

Each to his own.

 

Weather is gunna be nice again soon.....

[kc]

Nigel,  I have only just seen your posting of 26 May.  Obviously easier to stick to M5 if the brackets are made for that size.  My answers to your questions are that the Screwfix M6 inserts can be fitted either way - flange underneath might be  a bit stronger but on top has proved OK where they have been used for attaching all sorts of jigs etc to a workbench.    Several inserts have been inserted in my woodwork bench and model benches - used to hold anything down and yet leave a clear top afterwards.   On 13mm MDF they hold in extremely well.   If in doubt try on a scrap of material to get correct hole size.

 

My fuselage jig uses T nuts as it was made before the M6 inserts were available.   The T nuts tend to push out easily which is awkward.  Maybe epoxy them in or fit a strip of wood underneath to hold them in place and also stop them scratching the surface underneath.    I used white melamine faced chipboard which is handy to draw lines etc with a pencil and they wipe off with Cif cleaner etc.

 

[toto]

I like the idea of some epoxy on the T nut prior to pulling up into the underside of the wood. I'd also take an arbor bit to create a countersunk hole so the T nut doesn't protrude below the surface of the underside of the base. If that makes sense.

 

I have the stuff bought and ready to build mine but have not tackled anything that requires one yet. I have enough kits that will require one but don't see the point in building it until the time comes as it will be bulkier to store when built.

 

Toto

 

Toto.

[Nigel Heather]

On 03/06/2024 at 20:47, toto said:

I like the idea of some epoxy on the T nut prior to pulling up into the underside of the wood. I'd also take an arbor bit to create a countersunk hole so the T nut doesn't protrude below the surface of the underside of the base. If that makes sense.

 

I have the stuff bought and ready to build mine but have not tackled anything that requires one yet. I have enough kits that will require one but don't see the point in building it until the time comes as it will be bulkier to store when built.

 

Toto

 

Toto.

 

Are you going with MDF or Chipboard for your board.

 

I went with MDF and wish I hadn't as the drill holes are not as tidy (because the surface tears) and it blunts drill bits much more quickly.

 

As for using a spade or forster bit on MDF, this gets very untidy and blunts expensive bits very quickly  - the tidiness is not such an issue as it will be underneath, out of site.

Edited June 17 by Nigel Heather

[Andy Stephenson]

Drilling holes in MDF can be made much tidier if you put a piece of sacrificial wood hard up against the back surface. It doesn't tear on exit.

[kc]

 

As Andy says use the old,old trick of a backing piece of scrap wood.   Also a guide piece of scrap wood with a pre drilled hole held firmly on top to run the drill through makes a clean hole. 

Decent quality drill bits don't wear out much when used on wood of any type unless they are run much too fast and overheat.  

[toto]

I'll be going with MDF. 

 

Trying to get decent flat sections of Ply is nigh on impossible.  Especially if you are using B and Q. They all seem to be quite badly warped.

 

Cheers

 

Toto

[Geoff S]

1 hour ago, toto said:

I'll be going with MDF. 

 

Trying to get decent flat sections of Ply is nigh on impossible.  Especially if you are using B and Q. They all seem to be quite badly warped.

 

Cheers

 

Toto

 

Any sheet material is likely not to be totally flat - even MDF.  I used MDF for my SLEC jig but still screwed lengths of 2"x1" softwood edge on along the length. It's still flat many years later. The added advantage is that it keeps the T nuts, which are screwed in from the bottom, clear of the bench, although I usually save bench space by resting it on a pair of plastic trestles.  I made a general purpose building board out of a sheet of MDF with 2 layers of cork tiles and that is no longer flat because I failed to learn my lesson and didn't bother with stiffeners.  I use it upside down as a covering cutting table and not for building.

[Nigel Heather]

2 hours ago, Andy Stephenson said:

Drilling holes in MDF can be made much tidier if you put a piece of sacrificial wood hard up against the back surface. It doesn't tear on exit.

 

Yes this is true, though I am less bothered about tear out on the back.

 

But I'm more concerned about tear out on entry.  I have reduced this by drilling a hole in a piece of aluminium sheet and hold this down flat as I drill through it.

[Ariel]

Try Googling Nutserts for wood or threaded inserts for wood. They have a flange on top which hides any break out and don't have to go all the way through depending on the thickness of your board. If you can find Dowel Bits they will cut without damaging the surface because they have a point in the centre and cutting edges a bit like an Auger Bit. Twist bits will always damage the surface of wood or Mdf. 

If you are drilling through you need to back up the underside with a block of wood if you want to keep it neat.

[Nigel Heather]

21 minutes ago, Ariel said:

Try Googling Nutserts for wood or threaded inserts for wood. They have a flange on top which hides any break out and don't have to go all the way through depending on the thickness of your board. If you can find Dowel Bits they will cut without damaging the surface because they have a point in the centre and cutting edges a bit like an Auger Bit. Twist bits will always damage the surface of wood or Mdf. 

If you are drilling through you need to back up the underside with a block of wood if you want to keep it neat.

Tried those - I have now replaced them with the non-flanged type that I have inserted from underneath.

 

The flanged ones looked good in principle but need to be countersunk - and I found that countersinking MDF made for an untidy finish.  Also, the countersink bit (certainly the ones I have) would tear up the vinyl sticker.

[Ariel]

I would counterbore with an appropriately sized bit rather than countersink, however, you would need a depth stop collar for accuracy. 

Drill bits I was thinking of are sometimes known Brad point Bits.  I hope you come up with a solution.

[leccyflyer]

7 hours ago, Geoff S said:

 

Any sheet material is likely not to be totally flat - even MDF.  I used MDF for my SLEC jig but still screwed lengths of 2"x1" softwood edge on along the length. It's still flat many years later. The added advantage is that it keeps the T nuts, which are screwed in from the bottom, clear of the bench, although I usually save bench space by resting it on a pair of plastic trestles.  I made a general purpose building board out of a sheet of MDF with 2 layers of cork tiles and that is no longer flat because I failed to learn my lesson and didn't bother with stiffeners.  I use it upside down as a covering cutting table and not for building.

That's the construction method of the Peterborough Models fuselage jig that I use - two battens underneath keep the MDF reasonably square and keep the captive nuts well clear of the bench surface. Unless using good quality blockboard those stiffeners are vital, because MDF isn't stable or warp free until you have a substantial thickness of it - like a worktop.

[Nigel Heather]

9 minutes ago, Ariel said:

I would counterbore with an appropriately sized bit rather than countersink, however, you would need a depth stop collar for accuracy. 

Drill bits I was thinking of are sometimes known Brad point Bits.  I hope you come up with a solution.

 

With my experience with MDF I found that HSS drill bits worked faster and cleaner than the brad point wood drill bits.

 

For boring a recess for the T-Nuts I actually found spade bits worked better than Forstner bits, though neither were that good.

 

Remember, this is with MDF - with proper wood or chipboard it might be a different story.

 

Cheers,

 

Nigel

[Ariel]

For the level of accuracy and quality of cut you are looking for the only way I can suggest is to use a router and plunge cut. I worked a lot with mdf and veneered boards over the years and that was how we did it. The only issue is that you would need to make a jig to do it accurately, which kind of brings us full circle. You can get the holes in a straight line by using the side fence but getting them square across the board requires a bit more thought and not everyone has a router. I used to have a fully equipped woodworking shop and I wasted it making furniture when I could have been building model aeroplanes. The folly of youth!

I lashed up a magnetic building board and having proved the principle I must get round to building the mk2 version which will use an internal door blank as the base. Cheap. flat and light.

I would be interested to know what you come up with in the end. Old habits die hard and I'm always curious to see how other people do it.