Wooden Bar Clamp

 I couldn't find any complete examples of wooden bar clamps that used wooden screws for tightening.  However, I've seen a few examples of modern bar clamps that use steel threads with wooden bars etc.  The project started when I had a piece of partly dried sycamore that I could use to make a screw and some left-over ash and beech pieces. However, both the ash and beech needed to be ripped to size and for this I used my frame rip saw that I had recently made. It was a good opportunity to try the saw and in fact I soon found that the rip blade needed sharpening and the kerf adjusted as it was too wide. The saw then worked well as it cut straight without difficulty.

Screw spindle ready for threading. This was made using a branch of sycamore turned on the pole lathe.

The stock pieces ready for planing. The bar is ash and the arms are dried beech. The tightening spindle has been threaded (1/2 inch). 

My plan is to make a through mortice on the left-hand sliding arm and a through mortice and tenon attaching the right-hand arm to the ash bar. The first stage was to plane the stock to size. The bar was 53 x 23 x 545 mm and the arms 18 x 3 x 5 mm after planing with the hole for the screw 35 mm from the top of the arm. The sizes were mainly determined by the sizes of stock I had available but large enough to provide sufficient strength.

One side of the clamp fitted with the screw spindle threaded (3/4 inch) and the through mortice for moving the arm completed.

The spindle was threaded in the usual way after soaking for 2 days. The through mortice was firstly drilled through with a No 10 auger (drilling from both sides) and then finished by chiselling. Care was needed to ensure a tight fit and to do this the final adjustments to the arm and mortice were done using the joining plane (for the arm) and fine wood file for the mortice. A small chamfer was planed on each corner of the arm. I had considered making the top and bottom of the arm rounded but decided against this as it could jeopardise the fit of the arm. 

Showing the through mortice and tenon on left with dowels through and the moving arm with locators.

I made the mortice and tenon a very tight fit with dowels through and then drilled 5/16 th holes for the oak dowels into the beech arm. I then used these holes to position holes in the ash bar. Care was needed to get the holes in line when drilling with a brace and bit. Final adjustments were made with a round file. 

The end of the screw spindle was fitted with a pressure plate with a gaiter to allow the screw to be turned without the plate turning. This is a similar method to that I used in making the small wooden clamps. Small 6 mm dowels were used in a channel in the screw (as shown below) that was cut in the spindle on the pole lathe. After treating the threads with wax, this seems to be working well.

Details of the gaiter. The two 6 mm dowels are not shown

The finished bar clamp.

Two oak pegs are used to locate the moveable arm on the bar and in addition, a threaded hole was made on the fixed arm as shown. The threaded spindle can be easily removed by pulling out the two dowels in the pressure plate (they are a friction fit and not glued), unscrewing the spindle and then relocating it as needed. 

I am not sure how this can be improved, no doubt I will discover with repeated use! (any ideas will be welcome). I did notice a little movement on the moveable arm when a lot of pressure is applied using the screw even though the arm has no play when the locating pegs are installed. I don't think this will  be a problem as the movement is very small but I have noticed on one design that a small wedge was knocked into the top of the moveable arm to prevent the arm being pushed from the vertical.

Overall, this is a tricky job because of the need to get a strong joint on the fixed arm and tight fit on the sliding arm to the bar. I managed this and was pleased with the fit. I expect the use of a pillow drill would make the process easier but I like my augers and brace too much!!

Folding Frame Saw - Buck saw / Bow Saw

 I have made buck saws before and one that was easily folded to conceal the saw blade teeth. I have used oak and beech wood but for this I am using dried ash because I have some available. Also my previous folding saw used a 21 inch blade but this time I am trying a longer 24 inch greenwood blade.

This is the first saw I made, and the one I use now but it isn't a folding saw so needs to be taken apart for transporting.

None folding saw I made first. The arms are longer than the folding saw and enable a larger gap between the blade and the stretcher. This saw is made of oak from our kitchen cabinets in Dorset.

This is the first folding saw I made and gave to Emily. Again this was made from the kitchen oak cabinets and has served her well on her travels.

The folding saw ready for travelling. The saw teeth are protected and held so they can't damage anything when transported. I used hemp cord that lasted several years before it had to be replaced.

This frame saw is longer and uses 600 mm blades from Dieter Schmid Fine Tools (fine-tools.com). The arms are beech and the stretcher was made of oak as above. The handles were turned from beech and the cord is replaced by a 6 mm threaded rod with a wing-nut for tightening. I have a rip, cross-cut and turning blade that fits this saw.

Ash wood folding saw.

Anyway, onto the new saw. I started by planing a piece  of  ash stock to 22 x 50 x 660 mm to make the two arms. Next I cut a slot to accommodate the blade as the arms fold down over the blade. The blade is 20 mm deep so the slot needs to be about 22 mm deep and cut in the centre.

At this stage the arms are still in one piece as the groove down the centre is cut with a  plough plane fitted with a 1/8 th inch blade.

The plough plane (Record 044) didn't allow me to get to the required depth of 22 mm so I deepened the groove with a large rip saw. This was easy as the groove cut with the plough was already over 1 cm deep. I think this method is better than using two pieces of rebated wood glued together, the method I'd used before to make the grooved arms. Next I positioned the blade with the longest hole 15 mm from the inside edge of the arm and 34 mm from the end of the bottom of the arm, marked and drilled from each side. I then bolted one end of the blade into the arm and marked the position of the second hole for mounting the blade (the holes were 584 mm apart). This left about 5 mm of waste at the end of the arm. After drilling the second mounting hole, the centre was measured and cut. To enable the blade to rotate in the mounting, a small concave was cut in the groove under the mounting bolts using a small chisel.

The arms were then shaped semi- circular (about 2.5 cm diameter) at the top and bottom  using a coping saw, spoke shave and wood file. Also a small semi-circular indent (2.5 cm diameter and 1 cm deep) was cut very near the top of each arm to fit the tensioning cord.

The arms connected to the blade. The arms fold down to cover the teeth for transporting the saw, Further work will be done to shape one arm for hand grip and chamfering edges

Having prepared the basics for the arms, I planed some ash stock down for the stretcher to 31 x 24 x 612 mm and cut some arched tenons on each end. These were 30 mm long with an arch of 15 mm radius as shown in the photo. These were  cut in the normal way with a tenon saw and the curved shoulders shaped with a fine chisel. The mortices were cut with the saw channel running through the centre and going 1 cm deeper. They were shaped to allow some movement in the joint.

The shape of the tenon to allow movement of the arms during tensioning the saw blade

The joint ready for final preparation;  joint must allow some movement of the arms

The rest was straight forward, rounding edges, marking the tenons and I did some relief carving of an  ash leaf and then I treated with linseed oil and wax.

Finished frame saw for Rebecca with some decoration and pyrography to show matching tenons. I used 2 mm twisted hemp cord to tighten.

This is the saw folded and ready for transport. All it needs is a custom carrier bag!

 This frame saw was a little more tricky to get flat when tightened and I think this is because of the relatively narrow stretcher compared to my other saws shown at the beginning. Also ash is a lighter wood compared with oak and so ideal for carrying, it may prove less resilient, only time will tell.

 I noticed when I was visiting Sweden that some of the older frame saws were made differently. The stretcher went through the arms via a through mortices but the blade was tightened in the same way. I can see that this method as the advantage of perhaps being able to move the stretcher up and down the arms although some were held in position with a dowel (or peg) swivels through the arms. The blades were longer and wider and I guess designed for farming use on large timber; they looked pretty robust!

A selection of old frame saws seen in Stockholm. Some of the stretchers are attached differently from mine.

This saw is from a Spanish Naval Museum and is of a form described by Henry C Mercer (Chinese frame saw) without discreet handles. The blade is shaped at each end and held in place with iron bolts that can be turned to angle the blade if needed. I haven't seen this shape of blade before.

Another Spanish saw with a narrow blade (also shaped at the ends) and I think with wooden stems to hold the blade. The arms on both saws are slightly curved for some reason.