Help with a stubborn double through mortise and tenon

[RogerS]

I can understand your 'trauma' but a reality check ? If that was my first work bench I'd be dead chuffed at the sheer quality of what you've achieved.

 

[Ttrees]

On a computer now so can describe better.
Glue that crack shut and it'll be as strong as ever.
A block of aluminium or cast metal is great for transferring graphite to find a high spots in mortices, paring tenons, finding high spots in between double tenons, transferring graphite around the shoulder,
A block wood would be better than nothing though.
You could do something like this if you are concerned about the squareness of the tenons

Or if you have squared all round, a timber shim to check your shoulders are equal and use calipers for both tenons.

You might also find that you may have to go back and fourth a bit as one shoulder is contacting the timber before the other one.
Presuming your mortises are square, and the face of the mortised timber is square so the shoulder will butt up against it,
You might find getting a copy and drawing where the shoulder is contacting or bottoming out if scribbling on the timber is getting messy.
More of a case of getting it right you have a pair of tenons to do evenly.

Tom

 

[SteL]

It depends on how much and which way it's out of square. It could work in your favour - much like we fit vice chops to toe in to prevent racking - but it could also stop you pulling the vice chop hard against the bench at the screw end. Perhaps you could drill the hole for the screw and see how it looks once dry fitted?

That's a good point. I'm going to ensure the face is flat (again), check the mortise holes are square (now I know how to) and see if I can get it better then move on. I will fit the screw, do the dry fit as you say and see what it's like.
Cheers

 

[SteL]

Thanks, tTrees That's a great tip I'm going to try! That's similar to the tip on checking the mortise for squareness... has me wondering why I didn't think of it! Instead I'm trying to balance a square on tiny little shoulders!

Thanks for the help. I'll have a go.

 

[GarF]

If I’m worried about a joint locking up halfway through gluing up, due to expansion with the water in PVA, I tend to reach for liquid hide glue or West epoxy.
The hide glue is lovely and runny once it’s warmed up in a pot of hot water. Or you can vary the viscosity of epoxy by altering the amount of filler (normally filleting blend for jointing) to suit your application. Both have good open time for complicated glue ups.
It’s looking good so far BTW!

 

[Sundial Colin]

1. Where the cheeks of the tenon are too tight they will be bruised and this shows as a slightly shiny surface.
2. If this joint will be under a lot of torque, it may be worth wedging the tenons - a standard construction.

 

[SteL]

If I’m worried about a joint locking up halfway through gluing up, due to expansion with the water in PVA, I tend to reach for liquid hide glue or West epoxy.
The hide glue is lovely and runny once it’s warmed up in a pot of hot water. Or you can vary the viscosity of epoxy by altering the amount of filler (normally filleting blend for jointing) to suit your application. Both have good open time for complicated glue ups.
It’s looking good so far BTW!

Thanks for the advice, I'll give it a go with the hide glue.

 

[SteL]

1. Where the cheeks of the tenon are too tight they will be bruised and this shows as a slightly shiny surface.
2. If this joint will be under a lot of torque, it may be worth wedging the tenons - a standard construction.

I managed to get it closer by cleaning up one of the shoulders. Although I think I said I was 100% sure they had no high spots, I found one straight away this morning.

I also checked the mortise holes were all square (using the tip posted on this thread) apart from one of the sides. I took a few shavings off there to improve it. The tenons were square using the other tip posted here. It's still not in 100%, but the gap is about the thickness of my fingernail so I moved on and got the vice dry fitted. It all worked like a charm! I did take some more pictures but my phone battery died.

2 - I am pegging the joint from underneath. I can't think of the name ... where you slightly offset the hole on the tenon so it pulls it all together when you hammer the dowel in... whatever that's called that's what I'm going to do!

Thanks for the help everyone.

 

[Droogs]

drawbore tennon

 

[SteL]

drawbore tennon

That's the one!

Right, I'm just about to get some suede ordered fr the vice, some dowel for the drawbore tenon and more boiled linseed oil - oh and some epoxy to put on the bottom of the feet for when the rain comes under the door! I'm terrible for not finishing things, but this thing is dangerously close to being done!

 

[gmercer_48083]

When you have a tight fitting mortice and tenon joint, as you fit it... it will compress the fibers, and it will look kind of polished where it is too tight. Look for those polished spots, and determine why. I could be the mortice, or the tenon, or alignment, or out of parallel, or any combination of these. You need to determine why the wood fibers are being compressed and correct that. Since the wood is pine... the joint will be more forgiving because the wood is basically soft... and will swell when glued using pva glue. If all else fails and it ends up too loose, you can cut a saw kerf (hand saw) into the tenon and drive a glued wedge into it as you would when replacing an axe handle.

Another thought... have you tried flipping one of the parts? You may have corrected it and are merely putting it together upside down. a good tip is to always have reference marks that tell you which way it goes together. A simple but good tip.

 

[gmercer_48083]

I use cork...on a roll for my vices, glued with contact cement or double sided tape. Cheap, lasts, does not mar, and easily replaced.

 

[SteL]

When you have a tight fitting mortice and tenon joint, as you fit it... it will compress the fibers, and it will look kind of polished where it is too tight. Look for those polished spots, and determine why. I could be the mortice, or the tenon, or alignment, or out of parallel, or any combination of these. You need to determine why the wood fibers are being compressed and correct that. Since the wood is pine... the joint will be more forgiving because the wood is basically soft... and will swell when glued using pva glue. If all else fails and it ends up too loose, you can cut a saw kerf (hand saw) into the tenon and drive a glued wedge into it as you would when replacing an axe handle.

Another thought... have you tried flipping one of the parts? You may have corrected it and are merely putting it together upside down. a good tip is to always have reference marks that tell you which way it goes together. A simple but good tip.

I haven't tried it the other way - That'll be interesting to try! I'm pretty happy with it now and it runs nice and smooth while dry fitted. I didn't think about that fix if it goes wrong. These are the tips I'm having to learn as I go. cheers.

 

[SteL]

I use cork...on a roll for my vices, glued with contact cement or double sided tape. Cheap, lasts, does not mar, and easily replaced.

I've bought that Crubber (I think it was called that) by benchcrafted. I'll see how that gets on when it comes. I was eyeing up some of the Missus' handbags but was warned off them!

 

[Felix]

Just to play devil's advocate (and I'm not trying to teach anyone to suck eggs) - have you checked your square is err.......square? - A quick and easy check is draw two lines very close to each other (but not touching) - one with the body of the square to the left and the other with the body of the sqaure to the right. Draw the lines the full length of the blade. Do this on a factory edge of a bit of ply or other material. Key here is to have a very flat edge otherwise the test is pointless. Once drawn, if the two lines are parallel then you can have some faith in your square - until you adjust it that is........then you're back in unknown territory.... just rinse and repeat the above until you are confident that your square will set square along the whole length when you adjust it.

cheers

Dean

 

[gmercer_48083]

Go ahead and use her handbag... tell her I said it's ok.

 

[SteL]

Just to play devil's advocate (and I'm not trying to teach anyone to suck eggs) - have you checked your square is err.......square? - A quick and easy check is draw two lines very close to each other (but not touching) - one with the body of the square to the left and the other with the body of the sqaure to the right. Draw the lines the full length of the blade. Do this on a factory edge of a bit of ply or other material. Key here is to have a very flat edge otherwise the test is pointless. Once drawn, if the two lines are parallel then you can have some faith in your square - until you adjust it that is........then you're back in unknown territory.... just rinse and repeat the above until you are confident that your square will set square along the whole length when you adjust it.

cheers

Dean

Thanks. I watched that trick on YouTube a while back (think it was Paul Sellers maybe) and I went ahead and tested my adjustable square (A cheapo B&Q effort) and it was slightly off. I then tried my old small set square and that was good, although it only had to be square over 6 inches, then onto my old large set square and that was way out. So, before starting this project I bit the bullet and bought a Starrett combination square. I did the same test with that one and it was perfect. I'm just glad I watched that video before marking everything out!

 

[Eric The Viking]

Peter S. will wince, but my rule of thumb with M+T is entirely dependent on whether you can see the end of the tenon or not. If "not" then glue fixes most things! Your joint looks good, but...

...The first picture shows how close that pine board is to the heart of the tree. It will almost certainly continue to "move around" (cupping, splitting and other nasty things) because of that, and isn't suitable to use for fine work. You might get on better by just using less than half of the width of it (which gives you almost quartersawn), but moisture content, etc. also play a part. Pine isn't nice to practice joinery with - it's cheap, but unforgiving unless it has been well dried, has good grain, and your tools are kept extremely sharp.

I'd guess that, if you try again with some nicer wood, the problem will go away.

 

[SteL]

Peter S. will wince, but my rule of thumb with M+T is entirely dependent on whether you can see the end of the tenon or not. If "not" then glue fixes most things! Your joint looks good, but...

...The first picture shows how close that pine board is to the heart of the tree. It will almost certainly continue to "move around" (cupping, splitting and other nasty things) because of that, and isn't suitable to use for fine work. You might get on better by just using less than half of the width of it (which gives you almost quartersawn), but moisture content, etc. also play a part. Pine isn't nice to practice joinery with - it's cheap, but unforgiving unless it has been well dried, has good grain, and your tools are kept extremely sharp.

I'd guess that, if you try again with some nicer wood, the problem will go away.

There's always a but! So you're saying my beautiful face vice is doomed from the start! I did consider using a hardwood for the vice and first plank on the top of the workbench. If it starts to move around I'll swap it out with something nicer. I don't think I could make it thinner with it needing strength with it being the jaw of the vice. Thanks for the info. I'll have to do some research on reading wood and how it is milled etc. I wouldn't have the first clue how to tell what part of the tree it came from. I usually have to plane a board and get tearout before I know what way the grain is going.

 

[Eric The Viking]

Sorry SteL, I missed the context earlier - busy-ish day.

But yes, it will probably go on warping/splitting roughly on a horizontal line where you have the handle (which is where the centre of the tree was). It depends on how much the moisture content and temperature of where you keep it differs from how it was when rough sawn and kiln dried.

I still use the bench I made by hand 30+ years ago. It has a rather nasty slab of Nemesu (Meranti subspecies) as the front edge/face, and one jaw of my face vice. The other, moving, jaw is a mahogany (can't remember what though). Even though I was careful to take off the arrises from the edges and corners, that's still 30+ years of having to stop periodically to tweezer-out nasty splinters from fingers, etc. The excitement of that does wear off fairly early on.

Mind you it looked lovely when it was first finished - all neat and with clean lines...

... So you can go too far t'other way too, and use a wood that's far too tough. Not sure what I shall use when I rebuild it, but I will give the matter some serious thought before committing to anything.

A slab of beech would probably do well, or ash, but bear in mind that woodworm love beech, too, for quite different reasons. So if you are planning to keep the bench, it's probably worth treating it with preservative (spirit-based), or putting a finish on, to discourage the little blighters and reduce the speed at which the moisture content changes. Try to find something that doesn't have obvious rings in the end grain - gentle curves are OK, but tight rings will bring issues.

Custard was commenting earlier - he'd be the ideal person to suggest what to use instead. That said, pine would probably be OK if it was cut from the tree differently. Beware of knots in pine though, because of the resin they have in them that they tend to share with everything they touch.

I should also say in fairness that the vice is a Record 52E, so the front edge of the bench and the moving cheek are thin and well "supported" by the cast steel pieces in use. Nothing has split.