# Eclipse projection board...27deg



## woodbloke (29 Oct 2008)

As an excuse to get out into a cold 'shop tonite here's how I do my projection board for the Eclipse gauge. This is the stuff I need:







Draw a line with the protractor at the desired angle onto the surface of the mdf, in this case 27deg:






Set the sliding bevel to exactly this angle and cramp firmly to the board:






Offer up the plane blade under the bevel and then locate the honing guide onto the blade and tighten:






Cramp the blade and guide into one half of the new projection board:






and then glue on the second bit so it makes contact with the edge of the plane blade:






so that the finished job is thus:






I used the hot glue gun as Gidon thought...13 minutes, but I had to take the pics with the D60...Paul :lol: - Rob


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## toysandboats (29 Oct 2008)

Woodbloke, you make it so simple, I must get out there and make myself a couple.

Thanks for the tip
David


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## PaulO (29 Oct 2008)

Very neat. Being a bit more geeky I did a bit of trigonometry and skipped the sliding bevel stage.






You want to calculate projection (P) to achieve a honing angle (alpha + beta). W and R are functions of the honing guide. H is also a function of the honing guide for chisels, but for plane blades you also have to take into account the blade thickness. I chuck all this into a spreadsheet I devised and I get a graph showing honing angle for a given projection.






In hindsight the sliding bevel/protractor would have been quicker, but my office is warmer than my workshop.  Once the spreadsheet is set up I can work out the required projection for any blade and honing angle.

My plane blades get honed at 37mm (32 degrees) and polished at around 35mm (33.5 degrees). I know Mr C doesn't measure the projection for the polishing stage, but just pulls the blade back a couple of mm, as that increases the angle enough to ensure you are only polishing the front of the bevel, and the angle isn't critical.


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## Woodmagnet (30 Oct 2008)

toysandboats":165z6act said:


> Woodbloke, you make it so simple, I must get out there and make myself a couple.
> 
> Thanks for the tip
> David



I agree. 8)


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## MikeG. (30 Oct 2008)

Surely this is a classic case for a bench mark? I simply fitted my blade into the honing guide at the correct angle, then offered it up to the edge of one of my benches and marked where the blade came to with a pen. 

At least my way there will be no searching around for a small ply jig amongst the 100 other small ply jigs!!!

Mike


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## Derek Willis. (30 Oct 2008)

Use a Veritas jig and it is done for you!!!
Derek.


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## woodbloke (30 Oct 2008)

Mike Garnham":3ckvxm7r said:


> Surely this is a classic case for a bench mark? I simply fitted my blade into the honing guide at the correct angle, then offered it up to the edge of one of my benches and marked where the blade came to with a pen.
> 
> At least my way there will be no searching around for a small ply jig amongst the 100 other small ply jigs!!!
> 
> Mike



Mike - agreed, you could offer it up to a pen mark on the bench. The thickness of the pen line is negligible, but there may be a bit of parallax error as the edge sits above the bench by the thickness of the blade and unless you're eyeballing directly overhead there's a chance that you'll be looking it at skewed, in which case the distance you set won't correspond to the angle you want. With these projection boards, the distance and angle is guaranteed every time...and I just lob it in my sharpening drawer with all the other bits and pieces - Rob


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## bugbear (30 Oct 2008)

PaulO":2sllsotf said:


>



Since (even for bevel up blades) the actual variation with plane blade width iis rather small, I feel my approach of not caring too much about accurate bevels, merely repeatable ones, is nicely justified by this graph.

If one wants repeatable micro (aka polishing, or final) bevels, a thin (e.g. 2mm) shim can be used in the same gauge to give a related, but reduced, projection.

BUgBear


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## woodbloke (30 Oct 2008)

Derek Willis.":1plukzgn said:


> Use a Veritas jig and it is done for you!!!
> Derek.



...but can you set up *any* angle? I tried to set up 38 deg (as I said on the other thread) and couldn't do it, or maybe it was me :? - Rob


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## wizer (30 Oct 2008)

woodbloke":2653e10n said:



> Derek Willis.":2653e10n said:
> 
> 
> > Use a Veritas jig and it is done for you!!!
> ...



Yes you can, you can use one of your jigs with the Mk.II. But the Mk.II covers pretty much any standard angle, so most woodworkers won't obsess about an extra 2 degrees here or there.


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## woodbloke (30 Oct 2008)

wizer":5pcbwx2a said:


> woodbloke":5pcbwx2a said:
> 
> 
> > Derek Willis.":5pcbwx2a said:
> ...



Tom - which then begs the question...why spend £40 odd on a jig that you need to use with a homemade projection board (for a particular angle) when you can buy a jig for about a fiver that'll do the same job?...if you get my drift. It's just one of those little GOM things that irritated me the other day at Waka's when I couldn't make the VII do what I wanted it to do. As we said yesterday, the odd 2deg in the long run of things don't matter too much, it's just being able to make the tool do what *I* wanted it to do, _rather_ than have it dictate to me - Rob


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## wizer (30 Oct 2008)

I'm not qualified enough to comment on what percentage of woodworkers need those odd angles, but I'd guess it's quite low. I'd have thought such woodworkers wouldn't have bought that jig in the first place and if they realised after that they needed an odd angle, then they'd make the jig. I haven't ever read a Mk.II review that mentions odd angles and everyone I have spoke to who owns one has been happy with it. So as I said in the other thread, it's just a case of horses for courses. I really like the Mk.II, it makes sharpening a doddle.


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## Neil (30 Oct 2008)

Rob, there is a 38 degree position (well, actually 37.5 degrees) but its not labelled for some reason - just set the guide on the yellow position and set the scale to the mark labelled as 50 degrees for the red position. I agree with you, though - if you want complete flexibility about angles then you may as well stick to the Eclipse. The microbevel facility is nice, though...

Cheers,
Neil


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## woodbloke (30 Oct 2008)

wizer":1cdj5zuq said:


> percentage of woodworkers need those odd angles



It was just one of those angles that was picked completely at random, really just to illustrate that that the VII isn't quite the all singing, all dancing jig (note the pun  ) that it's made out to be. I agree that for most users, it'll do the job very well. The Eclipse jig also has it's limitations (skewed cambers :x ) which is irritating as well, so nothing is ever perfect - Rob


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## Derek Willis. (30 Oct 2008)

Whilst my Veritas jig is the earlier Mk. 1 model it does have sufficient choices for most people at, 15/20/25/30 and 35 degrees, more than enough for me.
Derek.


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## Paul Chapman (30 Oct 2008)

Derek Willis.":1md0c5ry said:


> Whilst my Veritas jig is the earlier Mk. 1 model it does have sufficient choices for most people at, 15/20/25/30 and 35 degrees, more than enough for me.



I assume you're referring to the angle setting device that comes with the Veritas Mk1. I've had one of those for years and never got on with it. When I use the Veritas Mk1, I now use it with a Woodbloke-style wooden setting block because I find it guarantees that the edge of the blade is parallel to the roller.

By the way, Rob, great definition from the D60 :wink: 

Cheers :wink: 

Paul


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## Paul Chapman (30 Oct 2008)

woodbloke":1gneacl0 said:


> Derek Willis.":1gneacl0 said:
> 
> 
> > Use a Veritas jig and it is done for you!!!
> ...



You probably can, Rob - but then you could also use one of your wooden set-up blocks. Here's one in use with the Veritas Mk2 and the Veritas skew rebate blade 






In fact you can use the wooden set-up blocks with almost any guide, provided the front part of the body is parallel with the roller.

Cheers :wink: 

Paul


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## Peter Evans (31 Oct 2008)

Dr Gary Heald wrote an articel in F & C #87 April 2004 p 57 setting out the mathematics. The key issue is that the thickness of the plane blade is important. The formula can be adapted to other guides as well.

For an Eclipse

Plane Blade thickness 
Required angle	Angle in Radians	
2	2.4	2.8	3.1	3.6	4.8
20	0.34906585	68.4	69.5	70.6	71.4	72.8	76.1
22.5	0.392699082	58.1	59.1	60.1	60.8	62.0	64.9
20	0.34906585	68.4	69.5	70.6	71.4	72.8	76.1
22.5	0.392699082	58.1	59.1	60.1	60.8	62.0	64.9
25	0.436332313	49.9	50.7	51.6	52.2	53.3	55.9
27.5	0.479965544	43.0	43.8	44.6	45.1	46.1	48.4
30	0.523598776	37.3	38.0	38.7	39.2	40.1	42.2
32.5	0.567232007	32.4	33.0	33.7	34.1	34.9	36.8
35	0.610865238	28.2	28.8	29.3	29.8	30.5	32.2
37.5	0.654498469	24.5	25.0	25.5	25.9	26.6	28.1
40	0.698131701	21.2	21.7	22.2	22.5	23.1	24.5
42.5	0.741764932	18.3	18.7	19.1	19.5	20.0	21.3
45	0.785398163	15.6	16.0	16.4	16.7	17.2	18.4
47.5	0.829031395	13.2	13.6	14.0	14.3	14.7	15.8
50	0.872664626	11.1	11.4	11.7	12.0	12.4	13.4
38	0.663225116	23.8	24.3	24.8	25.2	25.8	27.4

Note 
1	20º is about the smallest practical angle, a 2º back bevel needs a blade projection	of around 880 mm which is not really practical 
2	Chisels over 1.5" in width can use the plane blade base 
3	The instructions say 2" for 25º and 1.5" for 30º, so very close to Table above


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## Peter Evans (31 Oct 2008)

Formats badly, if you put into a table with a space as the column split you will see the pattern.


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## Derek Willis. (31 Oct 2008)

Back to the Veritas Mk.1 jig, using each pre-set angle, one can change that by 3 deg. by turning the knurled knob at the side giving 1 deg. each position, this, of course, is made so that a secondary bevel can be achieved, but can be used as one feels fit.
Derek.


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## bugbear (31 Oct 2008)

Peter Evans":vwa65boh said:


> <table>
> <tr><td><td><td>2<td>2.4<td>2.8<td>3.1<td>3.6<td>4.8</tr>
> <tr><td>20<td>0.34906585<td>68.4<td>69.5<td>70.6<td>71.4<td>72.8<td>76.1</tr>
> <tr><td>22.5<td>0.392699082<td>58.1<td>59.1<td>60.1<td>60.8<td>62.0<td>64.9</tr>
> ...



I think that convincingly demonstrates that blade thickness is no big deal.

For example, to go from 22.5 to 25 degrees with a 2.4 mm blade, the extension changes from 59.1 to 50.7, a change of 8.4mm.

But if, (at 22.5 degrees) we massively upgrade our blade from 2.4 to 3.1, the projection only changes from 59.1 to 60.8, a change of 1.7mm.

So (thinking backwards) changing the blade thickness for a constant projection does alter the angle, but not by enough (for me) to worry about.

BugBear


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## wizer (31 Oct 2008)




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## Paul Chapman (31 Oct 2008)

:lol:


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## Derek Cohen (Perth Oz) (31 Oct 2008)

"Woodbloke-style wooden setting block"?! ... Paul, this method has been around for yonks (e.g. BB has posted a pic of his jig a good many times as the occasion warranted it). It is interesting that we have a tendency to name a jig after the last person who uses it. 

Rob, I do like your tutorial here. My comment above should in no way be construed as a criticism, just a comment. 

In fact I like it better than an alternate method I have, which I will add to the pile. 











Regards from Perth

Derek


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## bugbear (31 Oct 2008)

Derek Cohen (Perth said:


> "Woodbloke-style wooden setting block"?! ... Paul, this method has been around for yonks (e.g. BB has posted a pic of his jig a good many times as the occasion warranted it). It is interesting that we have a tendency to name a jig after the last person who uses it.
> 
> Rob, I do like your tutorial here. My comment above should in no way be construed as a criticism, just a comment.
> 
> In fact I like it better than an alternate method I have, which I will add to the pile.



(chuckle) Hmm. That method requires a fancy gadget AND a horizontal bench!

BugBear


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## bugbear (31 Oct 2008)

On the assumption that was intended as an insult, consider me duly offended.

BugBear


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## thejhw (31 Oct 2008)

bugbear":v5l8i9rh said:


> Derek Cohen (Perth said:
> 
> 
> > "Woodbloke-style wooden setting block"?! ... Paul, this method has been around for yonks (e.g. BB has posted a pic of his jig a good many times as the occasion warranted it). It is interesting that we have a tendency to name a jig after the last person who uses it.
> ...



If the bench isn't horizontal, don't you just zero the gauge?

Jim


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## Derek Willis. (31 Oct 2008)

I just love the guage, never seen one,and would love to own one.
Derek.


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## woodbloke (31 Oct 2008)

Derek Cohen (Perth said:


> Rob, I do like your tutorial here. My comment above should in no way be construed as a criticism, just a comment.
> 
> In fact I like it better than an alternate method I have, which I will add to the pile.
> 
> ...



Derek - I came up with this method when I was trying to work out a simple way of setting the angle that didn't involve complex maths, calculus and fundamentals of trig...just a quick and easy practical way of setting any angle using bench tools that anyone ought to have in a 'shop - Rob


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## wizer (31 Oct 2008)

no need to be offended BB it's only a bit of fun.

I'm off to try the Derek Cohen Angle Method


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## Peter T (31 Oct 2008)

Derek Willis.":hod1sfk9 said:


> I just love the guage, never seen one,and would love to own one.
> Derek.



Just found them at http://www.rockler.com for $29.99 plus shipping.


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## Woody Alan (31 Oct 2008)

> Just found them at www.rockler.com for $29.99 plus shipping.



here is an alternative source in the UK.
I'm not sure rockler are cheap on shipping to UK, if you want to order from states ordering from Wixey direct might be best.

Alan


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## Peter T (31 Oct 2008)

Woody Alan":2ckecizy said:


> > Just found them at www.rockler.com for $29.99 plus shipping.
> 
> 
> 
> ...


 
Tried to do that but they want payment via PayPal, and they won't accept payment from a non-USA PayPal account!! 

I'm lucky in that I get stuff delivered to my US office and then pick it up next time I'm there.


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## gidon (31 Oct 2008)

You could try that ebay company's website:
https://www.machine-dro.co.uk
Cheers
Gidon


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## PaulO (31 Oct 2008)

wizer":ebvx2rj9 said:


> I'm off to try the Derek Cohen Angle Method



By Derek's own theory that method is now the "Wizer Angle Method"


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## Peter T (31 Oct 2008)

gidon":1hxpsmvm said:


> You could try that ebay company's website:
> https://www.machine-dro.co.uk
> Cheers
> Gidon



Even at today's poor exchange rate, they are charging approx. $44.

I got one for $29.99, a 47% saving.

Thanks anyway,


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