Portable (bench-top) Workbench

[arther dailey]

Next up was the tubes to run in the slotted bushes for the dual-screw vice. The original plan was to have these threaded onto the shafts, but I couldn't face another bit of 2.5 mm pitch thread cutting, so I just took a bit of the tube and skimmed the OD down to 25 mm to fit in the slotted bushes.

I then cut it off with the bandsaw, flipped it over, faced and chamfered and Robert's your father's brother:

My original plan with the holes in the wood for the slotted bushes was to rout them out once the brass bits were glued in place. However, I got impatient and wanted to do some trial fits before things got as permanent as being glued together. The brass bits are a close fit and are prevented from rotating by some dowel pins, so I figured it would be fine.

I fitted a top-bearing flush trim bit in the little router:

After very carefully setting the height so the cutter wouldn't cut brass, I worked steadily away at the holes until they were the same as the brass slot:

Something went slightly awry on the second hole - I think I wobbled a bit and lifted one side of the router up slightly. I don't think it matters though as it doesn't look horrendous and will be on the inside of the jaw.

With all those bits complete I could do another test fit:

Here it is with the top slid into place as well:

That brings us to a bit of a landmark: all the metal-mangling is complete (apart from whatever I decide to do about washers for the dual-screw end) and I can get back to some wood-worrying!

First job is to open up the slots for the vice mechanism bodies (to compensate for moving the shaft hole as I mentioned a while ago) and then I can do some functional tests.

wow,like just doesnt cut it

 

[Dr.Al]

Today I acquired...

Some spherical seating washers. I decided to take good advice and just buy these components. Until I can get round to making spherical turning attachment for the lathe, this seemed like the best idea. According to the dimensions on the website I bought them from, the convex parts should have been a reasonable close but loose fit on the bushes I made and the concave ones should have a reasonable amount of clearance for angular adjustment. The latter was true, but the convex ones don't quite fit. I'll have to mount them on the lathe and skim a tenth of a millimetre or so off the bore.

More on that later.

As far as actual work on the bench goes, I started today by drilling out the dog holes for the top.

I then put a chamfer bit in my small router and chamfered all the holes slightly.

There had been a bit of tear out on the bottom of the holes (despite having a backing board: I hadn't clamped the top to the backing board so I think they separated as the drill bit went through). To hide some (but not all) of the tear out (which will never be seen anyway as it's on the underside of the top) I did the chamfer a bit deeper on the bottom.

I then put the workbench together with clamps so I could mark out the hole locations:

With the top in place, six of the dog holes are over part of the feet:

I marked the hole locations out by using my 20 mm Forstner bit and pressing down by hand. I then followed that up with an awl to make the mark more obvious.

My plan had been to drill these holes out 22 mm to allow for some movement in the top (which will be attached with buttons). The holes in the foot will be there to allow clearance for longer dogs to be inserted, but they won't be providing precise location or anything, so 22 mm seemed a good size.

Unfortunately, when I came to drill the holes out, I came across a bit of a problem. I was sure I had a 22 mm Forstner bit, but it seems I'm wrong! The outer holes are also only 11 mm from the edge of the wood so that size Forstner bit is probably not ideal. I'm going to ponder on this for a bit. I could just cut the end of that bit of the foot off, but I quite like the fact that the edge of the foot goes up to the rail. I could also cut out more selectively (cut a U-shaped bit out of the edge). To be determined...

 

[slim_boy_fat]

Great work!

 

[gaz1]

 

[Dr.Al]

Putting the decision about how to relieve the holes to one side for a bit, I decided to get on with the buttons for attaching the table top. I started by setting the table saw up at an appropriate height and offset for one side of the groove:

Two passes on each piece later and I have grooves all the way round so I can put the buttons anywhere I want:

I used an offcut from the scrap bin (it had several nasty knots in it, so wouldn't be much use for anything else) and used the table saw to cut the button outline:

I then cut two strips away from the block and did a test fit:

The two strips of buttons were put in the vice and marked up. This is going to produce WAY more buttons than I need, but it doesn't take much extra time to make them en masse and I can pick the best looking ones at the end:

The holes were drilled and countersunk (a bit raggedly):

I then used my home-made bench hook thing to separate the buttons. The stop makes this very quick to do:

I now have a big pile of buttons!

 

[Dr.Al]

A very nice man sent me a bundle of strips of American Black Walnut.

I ripped three of these to size (two because I need them and one spare) and then planed them such that they were all exactly the same size. The actual size doesn't matter, but they need to match:

I then proceeded to play around with lots of ways of making a simple finger joint and concluded that it's quite hard to get it looking good! In the end I settled on using a biscuit cutting router bit:

I then extended the cut down with my dovetail saw and chiselled across the bottom to complete the joint.

I also took a long cut out on one of the pieces. I did this by cutting as far as I could safely manage with the table saw and then finishing off with a hand saw:

 

[Dr.Al]

With a small lump in my throat, I set my cross-cut sled up to take a big chunk out of the fixed jaw of the dual-screw vice:

Having cut round two sides, using the little "kerfmaker" knock-off to get the right width, I used my baby router plane (one day I'll find an affordable big router plane for sale!) to clean up the bottom of the groove:

This little router plane doesn't have any built in height adjustment, so I set it on a couple of feeler gauge pieces and dropped it into the groove:

The slot looks much better after routing:

I could then check the fit:

This little insert (which won't be glued into place so it can be removed when not in use) gives a right-angle reference for lining up dovetails, something like this:

It needs a fair bit of tidying up before it's complete, but hopefully you get the idea. In practice I'd probably put something under the tail board (and lift the pin board up accordingly) to reduce the risk of the knife cutting into the moving jaw of the vice.

 

[Screwdriver]

Dude, this is going to be waaay too nice to use. You might scratch it!

 

[Dr.Al]

This afternoon I started with a very quick job: drilling a hole in the end of the fixed jaw for the standard vice. The aim of this hole is to be a loose fit for an off-the-shelf dowel. I don't want to have to modify the dowel as I expect to replace it fairly often. It'll act as a sacrificial "saw catcher" when I'm cutting through stock close to the jaws. If I overshoot at the end of the cut, the saw will drop onto the dowel rather than onto the bench (or whatever) underneath.

I did some tests with a few different drill bits and found I didn't have one that was tight enough to hold the dowel without being too tight. 10 mm is too tight, 10.5 mm is far too loose. I dug around in my "antediluvian tools" drawer and pulled out a set of drill bits I'd inherited from my father-in-law with a 13/32" (10.32 mm) drill bit, but again that was too loose. In the end I settled for drilling 10.32 mm to a reasonable depth and then drilling a little further 10 mm. The dowel slips most of the way in easily and then sits firmly if pushed the last couple of millimetres. As it's only gripped at the last couple of millimetres, it's easy to pull back out again.

Next I fitted a stop block onto my router table (just a bit of wood clamped to the fence):

Then, taking a couple of millimetres off at a time, I cut a groove in one of the fixed jaws.

The result:

I then marked out and chiselled out an extra bit. This is (deliberately) not as deep as the routed groove.

With the foot in place, the result is a rectangular hole that's a loose fit for the dovetail guide I showed in the last post. The stepped bit in the top is a slightly tight fit in the section I chiselled out. When the dovetail guide isn't being used, it'll get slid into its home and will hopefully stay there but be easy enough to remove when required.

 

[Dr.Al]

Next job was (scary) to start to glue the first few bits together. Before doing that, I thought I'd get some photos of everything pre-gluing.

 

[Dr.Al]

The first bits to get glued together are the feet to the fixed jaws. The dual-screw vice end fixed jaw is aligned with lots of dowels and a bit of the tube that I've used for vice rails. The standard vice end is aligned with the two vice rail bushes. I got everything set up and mixed up some more Araldite (as it has a much longer open time than the wood glue).

I then glued and banged in the dowels and pushed the tube into place (without glue). I didn't take any more photos for a while after this one as everything gets a bit frantic when I'm gluing stuff together!

Finally (for this one) I pushed everything together, clamped it, wiped all (or at least as much as possible of) the squeezed-out glue off and then pulled the tube back out again (I'll glue that in later). The other end was much simpler, but before starting on the wood glue, I put some of the mixed-up epoxy on the inside of the flange where the vice rails (and the screw bush while I was at it) sit:

Since I was on a bit of an Araldite roll, I also epoxied the bearing block into the moving jaw for the standard vice and the two slotted bushes into the moving jaw for the dual-screw vice. The flanges were definitely a good thing on the other brass bits - there was a lot of messy squeezed-out Araldite at the bottom of the hole for the slotted bushes. I cleaned up as much as I could, but I'll have to do more when the epoxy has cured.

Here's everything clamped as it is now:

I also glued the hinge bars into place. To do this, I fitted each one dry, then slid it out one way and put a very small drop of Loctite 603 on the end, then slid it the other way and repeated that. I'm hoping that this results in the hinge bar being held in place but the nut still pivoting on the hinge bar. If it jams up I can always get it undone again with acetone or heat.

Finally I glued the dovetail guide up by clamping it to a small welding square. This will need more work to clean it up a bit, but I'll do that once the glue has dried.

That brings us to the end of the day's work. It's been a major step today as it's the first time I really can't go backwards and change something (without going shopping for more beech and basically starting again!). Hopefully when I go out tomorrow morning I won't find anything drastically wrong!

 

[selectedgrub]

Awesome.

 

[slim_boy_fat]

That is a major project you set yourself, and is beautifully executed.

 

[Dr.Al]

The feet/jaw assemblies look okay having come out of the clamps (although I won't know whether everything is aligned properly until I'm quite a bit further on, so I'm just having to hope for the best for now).

With the clamps all removed, I could put a bit more epoxy into the fixed jaw for the dual-screw vice:

The screw bushes for that vice could then be fitted and clamped in place:

The vice mechanism body for the standard vice could be fitted at this point. The other vice mechanism bodies will have to be fitted when the whole workbench is assembled as they need to be slid into place along the threaded rod: there's no access to the top of the body once the vice mechanism is fitted and hence there's no way to drop the hinged nut assembly into place. It'll be much more awkward, but all being well will only need to be done once!

I then decided to bite the proverbial bullet and fit the rails. In my mind this is the most scary bit as the movement of these rails in their bushes will either make the vice lovely and smooth to use or it will make it jam up and be next to impossible to use. I genuinely have no idea what I'll do if the latter is true!

I started by clamping the foot down to the workbench and fitting the rails into the rail bushes. I then slid the moving vice jaw on for a test fit:

Then I took a deep breath, plonked a load of Araldite in the bottom of the holes for the rails and then clamped everything together. I used the wooden rails that support the table top as spacers between the moving and fixed jaw: they're the same size as each other so will keep the two jaws parallel while giving some clearance just in case there's any Araldite squeeze-out.

 

[Dr.Al]

With all that epoxy setting, there isn't much I can do for the rest of today, but I thought I'd get on with one little outstanding job that could be done without touching any of the epoxied pieces: sorting out the bore in the spherical seating washers I bought.

There isn't much material to hold on to in the lathe, so I decided this was a job for my home-made soft jaws (made out of some hex bar stock I bought on ebay a while ago). Brass is an odd material for soft jaws, but when I was looking for some very large hex stock, there was a local ebay seller selling a bit off and it was cheaper than buying a length of steel from a steel supplier.

I started by clamping a bit of scrap in the soft jaws. The diameter of the scrap was chosen to minimise the amount I had to take off the soft jaws (to prolong their life).

With the jaws firmly clamped I could then machine a recess of the same diameter as the washer.

The washer then sits against the back of the recess and is held firmly on the perimeter:

Machining the bore was straightforward as I wasn't aiming for a very precise fit: it just had to slide over the flanged part that sits on the threaded rod.

While I had the soft jaws fitted and set to the right diameter, I decided to mount the convex washers and machine the face. They had a slightly rough finish and I figured it would mar the brass slotted bushes quite quickly without touching up.

On the first one I did I made two mistakes: I started the facing cut with the cutter very close to the piece and I forgot to switch the power feed from turning to facing. As a result, I took a light cut on the outside bore. I usually keep the cutter a little way away from the cut - that way if I have the power feed going the wrong way it just passes by the outside of the part. I was more careful on the second one!

You can see the result of my mistake on the right-hand most piece in this picture of all four pieces:

The parts then got a dunking in cold blue for a few minutes before rinsing in water.

The finished result after a quick air line dry and before coating with oil and leaving alone for the coating to harden.

The cold blue has hidden most of the evidence of my earlier mistake: you can still see it if you're looking for it but it's far less obvious now.

At the moment I can't think of anything else I can do on this until the epoxy has fully cured (14 hours according to the packet), so that's probably it for the day.

 

[Screwdriver]

Stands out a mile. You should start again.

 

[Dr.Al]

The problem with having nothing to do on the project while the glue dry is it gets me thinking.

I've decided to make a small (but awkward now that it's glued together) change to the design. I'm going to shorten the feet. At the moment, they stick out about 75 mm on each side of the body. I'm going to trim that down to 60 mm (or a little under). It'll still provide plenty of clamping area I think but will make the overall width of the workbench a little smaller (500 mm rather than 530 mm).

Updated CAD model:

The reason I want to do this is that I plan to keep the workbench on top of the table saw when not in use (and probably will also use it while it's on the table saw). At the moment the space on top of the table saw is occupied by my cross-cut sled. What hadn't occurred to me before now is that the depth of the cross-cut sled is 500 mm, so if the bench is that size or less, it'll fit neatly on the sled. If it's wider than that, I'll have to find a new home for the sled and I can't think of where that might be!

Cutting the feet shorter will be very straightforward I think: either with a hand saw or with the table saw and the cross-cut sled. What's going to be difficult is re-rounding over the edges. With the fixed jaws in place, the only way I'll be able to get the router to the end of the feet will be end on, but the surface area is far too small. Hopefully I'll be able to rig something up so that the foot (and it's attached jaw) is clamped to something firmly, but also have a raised work surface around the foot end to support the router base. Something to think about tomorrow anyway.

While I was out there pondering, I also decided that I'll probably screw the support rails into the feet and fixed jaws. I'd initially planned to glue them (and I still will), but I'd been considering dowels and such like. I think all that is too much faff for little benefit, so I'll cover the area in glue, plonk the vice rail in place and screw it down to both the foot and the fixed jaw. The screws will be hidden by the bench top. I've marked up where the holes will go, but I'll drill out the clearance holes, pilot holes and countersinks later:

 

[Dr.Al]

There's a word I've just been saying over and over again. One of its synonyms is "excrement". I clearly haven't had enough coffee this morning.

I went out this morning and marked up where I was going to cut the feet off to shorten them a little. I decided to go for 20 mm shortening rather than 15 mm as it looked like plenty. I marked all four feet with some pencil lines around three sides, then clamped one of the parts to the bench:

I then started sawing. This is how far I got before I realised I'm an idiot:

This is where the line should have been:

I marked up three of them correctly and one of them completely wrong and in my morning groggy state, I didn't notice that one looked completely different to the others and, of course, started with that one.

I haven't finished cutting through; I'm open to any suggestions! Thoughts I've had so far are:

• Cut it off where I've started and live with a foot with about 20 mm clamping area rather than the planned 40 mm ish. There's probably enough to clamp on (especially if I can hand sand the radius a bit tighter to give a bit more of a flat area).
• Fill in where I've cut (a triangular section that is I guess about 1/4 of the cross-section of the foot) with a glued-in bit of beech and live with the horrible looking bodge.
• Cut half way through, carefully chisel out a slot and put a bit of walnut in to make a contrasting thing.
• Curl up on the sofa and cry...

Anyone got any better ideas?!

 

[My Old Landy]

I haven't finished cutting through; I'm open to any suggestions! Thoughts I've had so far are:

• Cut it off where I've started and live with a foot with about 20 mm clamping area rather than the planned 40 mm ish. There's probably enough to clamp on (especially if I can hand sand the radius a bit tighter to give a bit more of a flat area).
• Fill in where I've cut (a triangular section that is I guess about 1/4 of the cross-section of the foot) with a glued-in bit of beech and live with the horrible looking bodge.
• Cut half way through, carefully chisel out a slot and put a bit of walnut in to make a contrasting thing.
• Curl up on the sofa and cry...

Anyone got any better ideas?!

None better but I would go for option 3 and add a nice contrasting bit. If you can't hide it, make a feature of it

 

[gaz1]

fill in with your sawdust and glue from your cuts push it in deep

you should be fine when sanded

but you will need to fine sawdust to fill that cut line

either that or use addons in a different colour on all 4 feet