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Flattening Jig

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darrenking
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Apologies for double posting but I thought I should probably post this under its own topic rather than hijacking TV's heading.

 

Ok, here we go. There may be a couple of minor changes for the production version but here is the Bagpress Flattening Jig prototype. Very happy to hear your opinions, comments and suggestions.

The prototype has a clearance of 50mm from the bed to the underside of the slide (is this enough?) and will take material up to about 380mm wide x about 560mm long. It doesn't currently have front and back stops for the router travel but if you guys think this is important then I can add these very easily, it will just make the slide section a bit wider. The side guides for the router are adjustable and should accommodate most routers, large or small.

The whole jig is currently constructed out of 18mm birch ply but using moisture resistant MDF for the base would reduce the costs a little if necessary and it wouldn't affect the operation or accuracy of the jig. I'll work out the price once I've had your feed back and incorporated any suggested alterations.

The top of the rails have been trimmed on my veneer saw which produces a very flat and accurate surface for the 5mm deep channels in the slider to run on. I don't think there is a need for any anti-friction material on the slider as a little bit of wax rubbed on the top of the rails produces a very smooth action.

The base is pre-drilled with multiple screw holes to allow for the blank to be securely held in the optimum position from the underside, and there are four holes in the corners to allow the jig itself to be screwed to a bench or a clamped baseboard.

IMG 2422
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Screen Shot 2021 04 18 at 16.32.23

What do you all think?

Cheers

Darren


   
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Russ
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@darrenking.

We'll Darren, to my now semi trained eye, I think it is fantastic. I would imagine that 50mm is deap enough to do the job but I don't know why but something in the back of my head is saying 70mm. 🤔? 

It's more great workmanship from you. 

Cheers,

Russ

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mattbeels
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I think it looks great @darrenking!

The height of 50mm sounds good but perhaps it’s right on the edge? Most body blanks end up around 45mm but depending on how thick it is before planing, it could be a bit tight. A neck blank for a set neck is about 50mm when planed so someone correct me if I’m wrong but I’m guessing a bit more clearance may be a good idea.

I think it would definitely need to be longer to flatten neck blanks as well as they are around 700 mm or so depending on headstock, scale length, number of frets etc.

But maybe this is just designed for body blanks? If so then I’ll just see myself out...

Personally I think end stops would be a necessity to keep from accidentally going too far and ruining the slide. 

Killer jig overall!

Practice on scrap...


   
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darrenking
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maybe this is just designed for body blanks?

Hadn’t thought about neck blanks. I could add about 80mm to the length without it too much of an issue and there is nothing to stop a narrow blank being held diagonally, which would also increase the usable machining capacity. I’ll draw the alteration tomorrow and see how the dimensions work out. Mentally, I had already committed to the router stops so I’ll add them tomorrow as well.

Cheers

Darren


   
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darrenking
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I’m guessing a bit more clearance may be a good idea.

OK, I’ll increase it to 60mm and if anyone finds that this it too high then they can always trim the rails down a little bit themselves. Sound like a plan?


   
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mattbeels
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there is nothing to stop a narrow blank being held diagonally

I had thought of that after commenting @darrenking but wasn’t sure if it was a whack idea or not. So I guess it isn’t! 😆

Practice on scrap...


   
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tv1
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You already know what I think @darrenking!

It's another beautifully made piece of kit from the Bagpress workshop.

My existing set-up uses a 50mm rail height.  The only downside with making it taller is that, if you also need to flatten something thinner, then your router bit might not be long enough to reach.  I've never had a problem with 50mm being too low, but it has been borderline too high at times.

Stops to stop the sled going off the ends of the rails is a good call.  I usually clamp mine to a bench, and the clamps act as the stops, but having something built into the jig would be beneficial.

 

Too everyone looking at this - I had some hands-on time with it yesterday.  It's robust and plenty strong enough to hold a router.  The sled moves smoothly up and down the rails.  It's pure win.

Wealden Tools do the perfect surfacing bit to use with the jig;

https://www.wealdentool.com/acatalog/Surface-Trim.html

@darrenking; the diameter of ^^^that cutter is 52mm.  Would that fit through the slot in the sled?

 

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darrenking
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that cutter is 52mm

This is a great cutter and I love Wealden products, and I think they offer the best value for money of any UK brand. My only concern is that this is quite a big cutter to be using in what is essentially a hand routing jig. Especially if someone is new(ish) to using a hand router I would probably recommend starting with smaller diameter cutter, maybe 25-30mm max as this will be more forgiving in case of an ‘incident’. A 52mm cutter will fit through the aperture in the jig though, so if you are happy to use it then go for it, just don’t take too deep a cut per pass especially early on, when the surface may still be fairly and the depth of cut not so easy to assess.

Smaller diameter cutters (15-18mm), such as those used for trimming kitchen worktops, are pretty cheap to buy and are significantly longer, so these are probably a good option for machining thinner materials even if it means having to make more passes.


   
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Russ
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My existing set-up uses a 50mm rail height.  The only downside with making it taller is that, if you also need to flatten something thinner, then your router bit might not be long enough to reach

A very good point @tv101. My idea of 70mm is ridiculous @darrenking. 🤔🙄 

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darrenking
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So should I go for a compromise of 55mm as standard to accommodate neck blanks?


   
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Boo
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It all looks good to me @darrenking it will be good to finally have a purpose made, flat surface routing jig. I always have confidence in you creations. 

Oh I got the buffing mops on Friday by the way (I sent you a text). Thanks very much. 

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darrenking
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The only downside with making it taller

That said, it is easier to add a riser layer to the bed of the jig to bring thin material closer to the cutter than it is to raise the height of the rails.


   
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darrenking
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Oh I got the buffing mops on Friday by the way (I sent you a text)

Hi Boo, no problem and I meant to respond. It’s just been a busy weekend, I’ve had sorts of odd people drop in!!😂😂😂


   
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Boo
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no problem and I meant to respond. It’s just been a busy weekend, I’ve had sorts of odd people drop in!!😂😂😂

Yeah I gathered you’ve had a busy one. Yeah there are all kinds of strange characters out there, be careful. 🤣🤣🤣🤣

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tv1
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I’ve had sorts of odd people drop in!!

You mean you had *other* visitors too???

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tv1
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My only concern is that this is quite a big cutter to be using in what is essentially a hand routing jig

Good point.  I should have said that I usually aim to take off *fractions* of a mm in each pass.  It works better that way too - leaves a much finer finish.

Ive got one of the blue Bosch 1/2” routers, which I keep for this sort of heavyweight task.

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Jonathan Hodgson
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I knew darren would come up with a fine design!

How easy is it to get a couple of clamps onto it to fix it to the bench?

 


   
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Tej
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@darrenking Looks brilliant, nicely done 🙂 another vote for adding stops, sounds like you’re planning to anyway! Only thing that would put me off is the wood on wood for the rails, given it’s for getting things perfectly flat might you get an issue with uneven wear on them. Might the middle tend to get more use than the extreme edges and wear more for example?

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darrenking
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How easy is it to get a couple of clamps onto it to fix it to the bench?

Hi @jonhodgson

Thank you for your comments.

You can either screw it directly to you bench or to a base board which can then be clamped to your work surface. The choice is yours.

Darren


   
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Jonathan Hodgson
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@darrenking

Thanks for the info.

That works, though if I was designing for myself I might have made the base a smidgin bigger than the rails so I could clamp without a baseboard (which makes it heavier to move about).

Then again, since I've been thinking of making an MFT style topped mini-bench maybe I'd do something with that, it's only horizontal movement I'd care about with this really.

Anyway, I'm pretty sure this is going on my "to buy" list... after the fret slotting and neck pocket jigs (The buffer will have to wait until I have my own workshop!)


   
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