Joining Methods Course last weekend (April 2011)

[John B]

This weekends project was based on joining methods commonly used in many situations,

How to make them, where to use them and how to plan the work to allow assembly and completion to take place.
with variations within each type of fitting, tenons, collars and rivetting,

With some theory and insights into basic methods and the reasons for using the different types of methods

The project selected was to be a candleholder which proved to be a greater challenge than first anticipated, mainly due to the fact we went with heavier materials than we would normally have used,

After chalking and talking some ideas, we came up with a basic, acceptable to all design, some more ambitious than others, (all component parts were completed, but not all yet are finally assembled, they will be completed at the students convenience either in their own workshop, or another session at Westpoint.

This was one that did get finished except for final cleaning and finishing which will be done at the makers leisure, and agreed with its recipient (Course was on Mothers Day so she will have the final say as to finish and where it will reside, brownie points were notched up)



First the materials, Main stem 20mm x 20mm (3/4"), Scrolls (and collars) 20mm x 8mm (3/4" x 5/16+"), base 40mm x 8mm (1.56" x 5/16+") Candle sconce 90mm (3.5") diameter x 3mm (1/8")

All the component parts were forged and the tooling and methods explained, the ones used, and other similar but different styles eg heel bars, profiled/shaped for collars, rivetted finishes etc, and were discussed as we proceeded to make them

When all the items had been made due to lack of time we concentrated on finishing one off so all would see and understand how to do it for themselves.

The particular one illustrated was designed to have a round dished disc candle sconce fitted and integrally rivetted to a pricket which was the pointy end of the tapered top on the central feature, (others will have different sconces and fitting methods use. Makers choice)

Assembling the finished seperate parts;

Rivet the central column into position, and adjust until base is level and column square to base.

Mark out for rivetting scrolls to base, drill for rivets, remove sharp edges on all drilled holes, and countesink under base for rivets.

Rivet the two scrolls on in position.

Make and fit the collars, Top one first lower one second., and here is how the collars were done.

First a mandrel the same size as the pieces to be collared, in this case just a couple of offcuts welded to another offcut from the stock we were using, this could have been a solid piece forged to te required size.



We then marked established the length of material we needed for a collar.



Fit the candle sconce, and rivet it in position, this was done by driving the disc onto the taper, heating the pointed end and then using a rivet set on the pointed end to in effect raise a head to grip the sconce. This rivet set had a deep bore so as not to damage the point of the pricket.

Then all there is to do is to tweak anything that needs it to the required position, clean up and finish as you (or client)like it.

Hope you enjoyed this and its of some interest, picture quality leaves a bit to be desired, but you should get the gist of it, any questions please feel free to ask.

[beth]

not sure what happened there! was just going to say looks like a great course john, and brilliant detailed post - photos are ace too! just wish i had more free time to get down to them. looks like you kept busy :)

[John B]

Busy, Had to put a bit of overtime in until we got one completed, will use a little smaller section material next time (probably), the finished item was only the second course the lad had come on, he completed the taster day a couple of weeks previously and fancied taking it futher. The other lad is just coming back to it after a break after starting a family.

[Don A]

Very nice, and very easy to understand.

I have yet to try collared joinery, but this will definitely be a primary reference when I'm able to give it a go.

Thanks for posting this,

Don

[John B]

Thanks Don, you may also be interested in the way we made the tenon, it went something like this.

Tooling we will be using; Curved Butcher, side set, set hammer and a square cornered block to fit in hardie hole if the anvil has bad edges.



We first punched a square hole through the base plate and used a ball end punch to countersink it from the base side (Not essential but we were demoing a technique and so it was included)



This gave us the finished size for the tenon we have to make, and we can use the punched plate as a bolster to monkey the tenon to fit nicely.

Heat up just the end of the square bar and upset the end by jumping it up, in this case by striking on the anvil from a height, truing it up and maintaining the shape as you go using hammer and anvil.



When this is done to your satisfaction you are ready to use the curved butcher to mark the shoulder all around for forming the tenon.

The curved blade marks the corners of the bar so you can turn it and continue marking all four sides, make sure the taper side of the blade is towards the end being used to form the tenon, this leaves a nice crisp shoulder to work from.



Using the side set, reduce the tenon to near finished size, equally from all four side, if the anvil edge is not a clean square corner, use a square edged block in the hardie hole, a sharp corner at the base of the tenon is not desirable,



but if it is not well supported when being forged, stresses may appear and weaken the tenon.

Finish drawing the tenon until it is a good easy fit into your previously punched base part, a set hammer can be used to tidy up all the sides and faces.



Tenon should be central to all sides


When the tenon fits, ensure that it fits nicely by monkeying it using the base plate over a bolster or swage block or in this case the prichel hole in the anvil.



When this is done allow the piece to cool, and then mark out to allowance for required finish, and saw off to length ready for rivetting.


This is then ready for heating and rivetting after all other parts are made and assembled to ensure everything fits OK

Tenons can be round or square, and it is inteded to make another tenon on the other end of the bar to mount a sconce or other fitting on.

Hope this is useful for those not familiar with this method of attaching bits together.

[John B]

Another finished item from this course with a different sconce fitting, this time held in place by drilling and tapping into the stem and securing with a countersunk 1/4" BSW screw

Sconce detail

Finished ready for cleaning up in his own workshop

[Spears]

Thanks for the progressive pictures. I like how collar thickness times two actually comes out decent for "corner bend take up" on four corners. I wouldn't have known how much to add on. If I ever do some collaring I will definitely give that a try. Most of the time when I do something so infrequently, I end up leaving it a bit long and trimming it off the hard way. It will be better to have a "come close" rule of thumb than wasting material. Thanks again. Spears.

[John B]

And another when finished

[Don A]

John,

Many thanks!

I've got a job on the drawing board right now that may well be joined with those square tenons.

Any hints for putting the square tenon on a piece with a rectangular cross-section (1/2 x 1")?

Don

[jeremy k]

Don - make them the same as in post # 5, the tenon doesn't know what the outer mat'l size or shape is, like John says - the tenon (in most cases) should be centered on the end of the stock. It is not uncommon to have a different parent stock shape compared to tenon shape.

[John B]

Hi Don, As Jeremy says its in the post, and tenons can be square, rectangular, round or other configuration should one be desireable.

I will mention Heel bar tenons here for anyone thinking of using them. traditional practice was to make the socket for the tenon to have radiused ends, by drilling or punching the ends where the tenon is to fit and then removing the centre of the tenon socket however you see fit, (chain drill and chisel then file, or slit and drift, punch etc)

The tenon itself is then forged and hot filed to fit the socket if necessary, this gives for a better join when rivetted.

Here are a couple of more pics from a bootscraper showing some different shapes/applications of tenons and where to use them

Firstly all the component parts laid out (minus the brush fitting details) the blade for the scraper crossmember has not been completed in this picture, because the position for the tenons on the blade is established when the posts and feet have been completed and hot rivetted together.



Make the tenon socket first as it is easier to forge a tenon to fit a socket, rather than make a slot to fit a tenon in.
These long tenon sockets were slit and drifted, the square one for the bootjack just punched through.and drifted to stock (rivet) size, as was the one in the squat ball and jack itself.



The tenon ends on the blade are cut to fit the assembly by whatever method you like, the position of the tenons on the ends should be made so the blade is horizontal to the ground level when finally rivetted up tight and in use.

I hot cut and hot filed the tenon on the first end until it fitted OK, and used the Handled side post as a monkey tool over a bolster/backing plate to ensure it bedded down nicely, and at 90 degrees.

Fit all items cold, (Feet and posts already rivetted together to form an item) and establish and mark out the position of the other tenon on the blade ie transfer the position of the socket onto the blade when the blade is parallel to ground level.

Then make the tenon on the other end as before using the other post as a monkey tool, bedding it down and again at 90 degrees.

The items were then cleaned up, and hot fitted/rivetted in a suitable sequence. Work your own out, if you don't think about the assembly sequence you can hit handling/holding problems during the rivetting stage.

These show the rivetted tenons when completed



The whole lot then cleaned up, brush holder fitted, finish painting sequence, then brush attached.

Finished item



Hope this is of some use for you, If you are confused feel free to ask and I will try to elucidate.

[beth]

so much information john - maybe its the heat, or maybe its the continuous and overwhelming realisation of all that i do not know how to do!! i feel li need to take a less random approach to my learning and sort out a few of these so called basic skills.... i dont know how to do ANY of these joining methods properly, i come on the wrong courses dont i! im going to go and carefully look at what i have missed this year from you lot, and piece together what i will aim for next year brilliant photo explanations john as usual, thanks for your time and effort for us all :)

[Don A]

John,

Again, I really appreciate the time you take with these explainations.

I would like to ask about your actual riveting process, particularly on a tenon. Do you heat the tenon in the forge, pass through, and rivet in that heat, or do you fit the tenon cold and heat the head with a torch?

I think I know your answer, but I wanted you to elaborate a bit, if you don't mind.

Thanks again,

Don

[John B]

Hi Don, each situation is individual and should be approached as such.

As far as is possible and practical my preferred method is to heat the tenon and end of the bar it is on to a high red heat, secure the bar, monkey the pieces together (set them as you should whenever solid rivetting) and rivet the protruding part with relatively light fast blows starting around the edges and working towards the centre to make the desired head profile.

By doing this the tenon in the socket can swell to take up any excess space, and more importantly, as the whole assembly contracts as it cools, it will tighten the joint even further.

If I am rivetting gates or similar large structures where getting it into the fire is a problem, then I will take a oxy/acet cutting torch to the tenon, and use a suitable leg vice clamped to the bar with the tenon on to hold it secure (as a bucking device to knock against) as far as is practical, the heat is concentrated into the tenon as opposed to heating the general area. I usually use more than one heating to complete the joint.

The leg vice is a free standing/laying down unit, and I usually wedge or clamp it to a table with the workpiece held in it so that it is held solid for rivetting against.

As a general observation, I find a lot of people have problems by using too heavy blows and also having too much tenon protruding before starting, countersinks/chamfers can also be useful when rivetting thinner sections to heavier ones.