Sliding Bevels: A Cautionary Tale

[DTR]

Morning All,

Whilst working in the square can be a bit pedestrian, working in angles has always filled me with trepidation. Yesterday afternoon was no different. Knowing all too well my own ineptitude I thought I would check and triple-check my marking, and it just didn't add up. One minute the angle was bang on, the next it wasn't.

After copious head-scratching, I came to the conclusion that the problem could only be my sliding bevel. Much has been said about the accuracy of a combination square, but it never occurred to me to check my bevel square. After all, it's meant to move! Well it turns out that my bevel "square" is anything but.

I'm not usually one to apply engineering techniques to woodwork, but I made an exception. I measured the stock at either end, and discovered it wasn't parallel. From end to end it was out by 1.25mm. This does of course mean that the bevel can only be relied upon when the same reference face is always used, which isn't always practical. I then noticed that the stock faces weren't parallel with the jaws of my vernier callipers. Upon checking the cross-section of the stock with a square, I found that it was off. Waaaay off.

Being as I have an occasional engineering fetish, I took matters into my own hands. I milled down the faces of the stock so that it was square and parallel (rather useful things, those milling machines). Two of the brass embellishments parted ways in the process, but ho hum.

I reassembled the sliding bevel and tested it again. This time it was much better..... but still not quite right. I checked the stock again and it was definitely parallel. Could it really be possible that the blade was off too?

Yes, it could. From end to end, the blade tapered by 1mm. At this point I decided to quit while I was behind and have a cup of tea.

Was I being naive to think I could reference off all the bevel's faces? I really should have known better; the bevel is unbranded but I strongly suspect it's a S*lverl*ne.

Obviously this all leads to the inevitable question:




Where can I buy a decent sliding bevel????

 

[AndyT]

Mine are all old ones, so no direct experience. But these are all made in Sheffield, where they ought to know what they are doing.

http://www.toolnut.co.uk/products/measu ... ing_bevels

But with your skills and your milling machine, don't you want to make your own?

 

[Glynne]

Thanks for posting Dave.
It's one of those really obvious things that is only obvious when someone points them out!
For someone who regularly checks his squares (especially after I've dropped one) it has never occurred to me to check my sliding bevel.
Off to the workshop in a few minutes and I'll just have to check....

 

[Peter Sefton]

I suffered the same problem once, you could try one of these, but I can't tell you where I got mine from...

http://www.igagingstore.com/6-Stainless ... 203949.htm

Cheers Peter

 

[pcb1962]

I use one of these
Perfectly straight and square. It's a little large for some jobs, and the wing nut thing on the end is a piece of stupid design because you can't turn it when the tool is lying flat on a surface. Other than that it's a good tool.

 

[Sheffield Tony]

Ah yes, well worth checking both old and new tools. I had a Silverline mitre square that was a degree out. And of a batch of old tri-squares there was almost every defect possible; the brass facing of the stock worn to a taper, the blades worn into a concave curve with use, etc. Mostly easily fixed (except the Silverline that went back).

I was going to say Joseph Marples, but I see Andy is there before me. I got a replacement for the noddy Silverline mitre square from Marples, and it is ... rather better.

 

[Ttrees]

Why stop now, you've got half way there ?
Have to check mine now since you brought it up (hammer)
Thanks

 

[bugbear]

...the blades worn into a concave curve with use...

I had to fix the rule from a s/h M&W combo square; the blade was around 1/32" concave on both faces.

Not only would it (therefore) not make a straight line, but given how a combo square works, it was never square either.

I worked one face of the rule to straight via a surface plate, and rendered the second side parallel
to the first (and thus also straight) using a micrometer.

BugBear

 

[DTR]

Thanks for the suggestions chaps

don't you want to make your own?

Life's too short! And if I don't finish this under-stairs cupboard for Doris soon, my life will be considerably shorter.....

I use one of these
Perfectly straight and square. It's a little large for some jobs, and the wing nut thing on the end is a piece of stupid design because you can't turn it when the tool is lying flat on a surface. Other than that it's a good tool.

I'm intrigued by having the nut at the end of the stock; I thought it would be out of the way there. I understand they lock better too. The Amazon reviews say they're plastic though?

Why stop now, you've got half way there ?

Because the blade looks like it's either hardened or Spring steel. I'd have to grind it. Not impossible, but I question how much polishing I can justify on this cowpat.

I think the Marples is my front runner at the moment. I welcome more suggestions, but I will have to order one soon before The Wrath of Doris is incurred.

 

[pcb1962]

I use one of these
Perfectly straight and square. It's a little large for some jobs, and the wing nut thing on the end is a piece of stupid design because you can't turn it when the tool is lying flat on a surface. Other than that it's a good tool.

I'm intrigued by having the nut at the end of the stock; I thought it would be out of the way there. I understand they lock better too. The Amazon reviews say they're plastic though?

The orange bits are plastic, but the reference faces are aluminium...

 

[DTR]

Noted, thank you. It does look very similar to this one offered by Axminster, minus the tangerine:

http://www.axminster.co.uk/japanese-shi ... vel-100885

 

[Corneel]

Mine are all old ones, so no direct experience. But these are all made in Sheffield, where they ought to know what they are doing.

http://www.toolnut.co.uk/products/measu ... ing_bevels

Anyone having experience with these Crown and Marples ones? Are they good quality, are they square and true?

 

[Ttrees]

Why stop now, you've got half way there ?

Because the blade looks like it's either hardened or Spring steel. I'd have to grind it. Not impossible, but I question how much polishing I can justify on this cowpat.

Can a single cut file not do the job ?

If you made a post about it ...one suspects that your not the type to throw these things away
and therefore you stand the chance of it, making its way towards your bench again unknowingly !!!
Be it a well intended student visitor, or when you turn that drawer upside down in haste when Doris wants those picture hooks ...
I have the solution ... Send it to me for proper disposal =D>

 

[Blockplane]

Thank you. Not something I would have thought of.

Having checked my two cheapo ones, I find that both stock and blade have an error in the order of 0.8mm between the two ends.

Not decided yet if that justifies corrective action, or a shopping trip.

 

[woodbrains]

Hello,

The simple answer is to use the angle from the sliding bevel ONCE to make a master template and use that, (after checking it is correct). Sliding bevels get knocked, dropped or otherwise reset, a template will stay true.

Mike.

 

[DTR]

So I bought the Shinwa bevel from Axminster....

http://www.axminster.co.uk/japanese-shi ... vel-100885

The Bahco bevel was my frontrunner, but I was discouraged by more than a few online comments about it not locking solid. I do however concede that probably the majority of bevels out there are fine, as evidenced by PCB's example. There were also a few comments about the current Marples variant being poorly finished.

I am satisfied with the Shinwa. It locks up solid, and both the stock and blade are parallel in width within practical limits.

 

[MusicMan]

Here's mine. Blades and handle are parallel to better than 0.05 mm. The 15/11 on the handle is not the date, or only indirectly. It's 15s 11d, which was the price when I bought it new as a student. That does date both it and me!

Keith

 

[Derek Cohen (Perth Oz)]

For some builds I can use 2-3 sliding bevels.

I am fortunate to own two made by Chris Vesper, in 4" and 7". There is also the best production vintage sliding bevel made, the Stanley #18. What I like about these three is they are easy to adjust and secure, and they lock down like a vise. The Vespers are built like a tank.

The rear two are cheapies, but they do the job: one is craftsman made, and the other is a Marples.

I can't say that I have ever measured any for accuracy.

Regards from Perth

Derek

 

[woodpig]

I've got the Bahco one and it's pretty good, no problems with it locking.

 

[memzey]

I have a few sliding bevels and completely agree with Derek on the Stanley #18. My favourite of the bunch.

I'm least fond of the one with the awkward locking lever on the left, which means you can't use it in certain orientations. The teak one in the middle with the screw mechanism is very good but not quite as convenient to use as the Stanley. It is well made though. Anyone familiar with the maker?