Well today I manage to finish tapping both top and bottom sets of securing bolts before making a fixture to cut the 16 or so bolts to same size. Once this was done it was over to the milling machine to firstly cut three slots before switching to the cutter to make the 'T' Slots. this is a messy job and certainly made my arm ache. I must get the power feed sorted out!

'T' slots mikked into the first part of the table top

I also forgot to change the speed of the milling machine and it didn't take long to for me to realise! So after changing the belts to get a much slower speed it all went well but I didn't feel up to continuing on with the long top plate. Hopefully next time it won't take too long to finish the slots. I will then make three supports from brass square bar so I can add a cover (steel) if I feel I need it.

Overnight I considered how to make and fit a safety guard for the saw table project. So at breakfast time (0600) I took pencil and paper in hand and roughed out a design that I thought may work. When going out into the workshop my first task was to see what materials I had that could be used for the design.

So armed with some brass angle and sheet brass I started to mark out my design. I must admit it would have been easier if I had made the guard from stiff cardboard as I have done previously but for some reason I forgot to do this until I was a fair way through the making of the guard.

Fortunately the spare blades for the Proxxon bandsaw had arrived from Chronos and it was really nice to cut some brass sheeting with a new blade! It reminded me that the new saw table would be ok for some tasks relating to sheeting (differing materials) but I should forget my trusty Proxxon.

After making the brass back plate for the guard I fiddled for quite a while trying to work out how I could fit it without the guard fouling the blade. I wanted to offset the pivot point to clear the end of the saw pulley but the circle of movement was then moved. In the end I decided to adjust the slot in the top table to give me the clearance required. Simple to write but that was an hour or so gone!

To form the top of the guard I decided to use brass angle and to allow the curvature required I cut slits at ½” intervals using the bandsaw and then drilling holes in the centre of each newly formed tab.

I mulled over whether to silver solder, bolt or rivet the angle in place and in the end thought that copper rivets against a brass fitting would contrast nicely when it came time to add some ‘bling’. The brass angle was held in place with 4 equidistant temporary 4BA bolts whilst all the holes were drilled before the inside holes were countersunk so the copper would have somewhere to go. This will help the rivets hold the two parts together.

With the outer part of the guard in place the final slotting of the table top could be done and a piece of brass angle was used to form the pivot bracket. it is secured to the underside of the table top which is where I got to at the end of the session. However I may have another problem to overcome since I made sure the work was done when the largest saw blade is at its highest position. When reflecting on what needed to be done next time I thought that the system may not work! When the saw blade is lowered the guard does not go with it!

My initial reaction is that the guard will still serve its purpose if it sits above the blade but just on the edge so that when it is lowered it does not foul. If that isn’t a solution then I will have to rethink how the guard can be secured to the saw pivot arm. And that would be a problem!

The guard will be held in position by a spring once I have the system sorted out. Again, don’t take too much notice of the finish of the parts since it will be dismantled when finished and ‘blinged’ up then…….

Rivets being used to secure the brass angle that forms the top of the guard

The brass angle being formed around the template

Trying the template to see how to fix it in place

The overall circumference was cut out using the Proxxon Bandsaw

Over the last couple of sessions I have made some progress on the saw table project. Today I completed the quadrant for the saw height adjustment and assembled all the parts to date. I decided that the next job would be to give the back plate a little ‘clean up’ and used a wire brush in the milling machine to polish off the marks that naturally occur when making an item.

Now that the mechanism was complete it allowed me to make up the drive belt which I found more difficult than expected. I tried out the process on a couple of scrap pieces and simply melting the ends produced all sorts of results. After some practice I managed a reasonable result that allowed me to make a good joint on the proper belt.

When running the system for the first time I was pleased that all turned as expected and the drive from the belt worked with varying tension settings. After 30 seconds or so the whole thing stopped dead. The pulley that holds the gear wheel on has seized up. On investigation the bolt holding the pulley on had tightened itself up sufficiently enough to stop it. The design was not meant to rely on any securing method to impact on the pulley turning. I had turned the shaft so that it extended beyond the brass pulley and in theory it should have worked. When looking at the problem further I thought that perhaps I had not left enough showing and all sorts of ideas came to mind particularly taking some of the pulley width off.

However the answer was simply to change the washer on the end of the shaft from one that covered the whole bearing to a much smaller one that only covered the end of the inner shaft. This cured the problem so the motor was started again and run for a couple of minutes before the saw blade stopped again. This time it was the pulley that holds the saw blade that had seized. Looking closely it was the shaft that was binding and I simply took a couple of thou off the end of the shaft being careful not to reduce the shaft part that the bearing sat on.

The motor was started again and all ran as it should do. I then varied the height of the blade to the two extremes and tensioned the belt to suit. All ran well and I will now be able to cut the studding used for the blade adjustment.

Suitable pleased I thought I would make a start on the top plate and soon produced the first part of the top with the slot for the diamond grit and two sizes of saw blade to fit in. This was placed in situ and I thought I would just ‘try’ the blade to see how it would cut. I am glad I did since I will have to ensure that any clamping system will take into account the kick back effect found when cutting some brass sheet. I then tried a ¼” diameter steel bar and you can see the results in the pictures. It wasn’t really a proper test since the bar wasn’t held properly but it actually cut better then the brass sheet. I have no doubt about the blades ability to cut. Then I tried the end of the HT steel that bar that started the whole project and was really pleased to see the small cut that appeared in the end of the bar! It will cut it and that’s good news.

So today’s session really is the beginning of the end…………………………………..watch this space.

Today was another short session but at least it was a session! I continued to work on the handle assembly for the belt tensioning system.

After turning down the brass for the main part (it’s the nicest cutting brass I have ever used) the centre was centre drilled, drilled and tapped to suit the studding. I am not impressed with one aspect of my design however and will decide on whether to amend it now or see how the whole assembly pans out.

I have thought of a solution to the problem but may wait to implement it. The design fault centers on the handle which moves away from the saw table when in use. My solution will be to make a fork which then fits into a grove that will need to be cut on the handle boss and the fork secured to the saw table. That would allow the handle to stay in place and the studding would pass through its centre.

I did consider remaking the brass block which moves in the slide and holds the pulley, but the studding would need to pass through it instead. I prefer the fork option at the moment but will see how it all works in operation before making a decision. The next piece made today was the handle and I decided to make it from aluminum as a contrast to the brass and turned a taper towards the handle.

This was then clearance drilled to suit a 6mm bolt. The final task was to drill and tap a hole for a grub screw in the boss which will secure the handle assembly on the studding. That completed the handle.

The next session will focus on making the assembly to adjust the height of the saw blade. I may use a similar set up to the belt tensioning system but will think about it overnight. If you would like to see a larger picture just click on the one your interested in.

 

Well I decided that I would spend this week on the saw table (fingers crossed!) whilst I wait for a few items for the Fowler traction engine. Today I completed milling the inserts for the tensioner pulley system and the saw arm guide (see photo's below). Not a great deal done but at least I was out smelling the oil again! 

Once I have done the saw table i will get the tender to a first fixing state before putting it on the back burner to go full steam (sorry_) ahead with the two Seal engines. It seems so long ago since they were out of their boxes!.

Toothed gearing to adjust saw blade height

Fowler awaiting the tender

Fowler awaiting the tender

My time on the workshop has been a little intermittent over the last couple of weeks but I have been able to get out there to make some progress on the saw table. I have converted the shaft of the motor to take a Myford gear by milling a slot in the shaft to accept a keyway and drilled and tapped the end of the shaft so I can secure the gear.

I have also made three pulleys, one of which is the important pulley that will hold the 2 saw blade sizes and the diamond grind stone. However I have decided today to make a separate pulley for the diamond grit stone. I have had to do this since assembling the pulley with the saw blades my initial idea to hold the blade on was to secure the pulley to its shaft and have a washer between the end screw and the blade. This didn't work on trialing it so I decided that I would thread the outer part of the pulley (see photo's) which meant the seating for the smallest item (the grinding wheel) would disappear but I want the blade to stay on and not spin past my ear!!!

The completed and newly threaded saw blade pulley

Fortunately the diameter of the end of the pulley was suitable for a 10mm thread and a corresponding nut was made by threading some 1” diameter brass then making two flats opposite each other that will allow a spanner to be used in conjunction with a brass spacer. I must admit I was very pleased with the results and either blade can be held very securely.

With all three pulleys and their shafts completed the focus now is on the fittings for the back plate. The brass insert for the shaft that drives the rest and on which a gear is held has been completed and the saw arm and saw pulley slot with it radius has been cut but there is still work to be done before fitting to the back plate. Another similar slot to the gear pulley needs to be made as well. When those items have been tackled next and fitted I will be able to finalise the belt size and test out the speed to the blades.

The brass insert deigned to increase durablility and the radius milled to suit range oof movement

Once the moving parts as it were are working fine I will then cut the teeth on the saw arm and the height quadrant (yet to be made) before making the threaded parts to move the quadrant and therefore saw adjustment.

Next week though I will be working on the Fowler traction engine before returning to the saw table the following week. I have decided to try to work on one of my three main projects (the pair of Seal engines, Fowler traction engine and saw table)for a week then back to one of the others. Whether this works will depend on my health though and how much time I can spend in the workshop. Life as ever is always a compromise.

Carbide tipped saws have been recommended for metal work in the past, especially when they are slitting saw size. In the UK I couldn’t find a supplier of small blades but a HMEM forum member (from Canada) sent me some blades to try. There are some really nice people in the model engineering fraternity. I am sending a traction engine book back to Canada (as soon as it comes back into Amazon stock!) but thanks are in order.

Instead of just trying the blade in my slitting saw arbor I thought I would bring forward an idea I had about building a saw table. The reason I wanted to trial the carbide tipped saws was to cut a round bar in half so I can make two crankshafts for the Seal build. Since the camshafts have now been made the next major item for the Seals is the crankshafts, so you can see all roads in fact led to the saw table.

Since I don’t sleep very well I often ponder designs during the night, scribbling down some drawings at my 0600ish breakfasts. I started by writing out the design criteria at one of these breakfasts, with the aim of making some CAD drawings, leading to a set of plans (Alibre) which could be made available on my website.  So this particular project covers many areas of interest for me. Such as making a workshop tool, using CAD, and helping with the Seal twin engine project. Not a bad result really.

The design criteria covered such things as having two blade sizes (the larger ones found in the UK as well as the smaller ones from Canada) so it would be useful to be able to use both blades on the same machine. The blade depth of cut should be adjustable and by a measured amount. The top should be as adaptable as possible, allowing the safe holding of materials. The blades should have some form of safety guard and make use of an existing electric motor I have.

Other ideas will no doubt come up as I progress, especially in the area of the work holding. I don’t feel confident enough yet to just draw the design out in 3D CAD. Rather it will be a bit of both, build and the use of Alibre CAD. The help in laying out the plan I used some foam rubber/plastic as a former to check the size of the saw arm and the quadrant. By using these materials in a mock up I discovered my initial quadrant lever would not work so a new shape was soon cut out and tried.

Since I have several ¼” (0.250” or 6.35mm) sheets of aluminum ‘recovered’ from my local scrap yard I wanted to use these to make a strong box shaped saw table (please see photo).The first task was to check the speed of the electric motor. I have a rev counter which measures revolutions from model aero engines and made up a temporary shaft to hold the Mills propeller. The measured speed was approximately 1200 rpm. The saw blades run at around a maximum 6000 rpm so I needed to increase the speed from the motor.

I had a look at the spare gears from the Myford and there were both 20 tooth and 65 tooth gears that can be used.  That should give me around 4,000 to 5,000 rpm at the blade. With these speeds I decided that all pulleys will have bearings and it was whilst searching for bearings I saw a diamond grinding wheel that would also fit the design. So I ordered the bearings and the diamond cutting wheel.

Now the project has turned into a versatile saw and grinding table which longer term I would also like to develop to grind camshafts in the future. Madness you may say (and you may well be right!) but if you take the saw table top as a base for holding various fixtures, then it should be an ongoing (maybe years) development for my own tool centre.

The rough design schematic is shown in the photo below to help you understand where I am going. To make the blade/grinding wheel adjustable I will use a quadrant with teeth cut into it, matching with teeth on the saw/grinding wheel arm. With the screw thread used for adjustments I should be able to make fine and measured cuts. Since this movement involves the arm then the pulleys will need to have a tensioning system to take up the difference.

Since I hope to have the tool for many years I will also be looking at the materials used, for example the saw arm needs to have a guide and clamp to secure it when any adjustment has been made. Just cutting through the aluminum wouldn’t really serve long term so I am letting into the plate a brass section (made from two lengths of square bar silver soldered together).

The drive belt I shall be using is circular in cross section and the two ends are ‘welded’ together (see photo), access to the belt as well as the gears (in case I need them on the Myford) and saw/grinding wheel needs be incorporated for change of belt, blades or now the additional grinding wheel.

Leaving design for a moment I made a start on the main pulley that will hold either the larger saw blade on one section or the smaller blade or the diamond grind wheel on another, since they have the same bore. The front of this pulley will have two diameters for the blades/wheel and the rear of the pulley will contain a sealed bearing.

So far the pulley has been turned to outside diameter and the belt groove done (photo). The bore has been drilled and reamed with a start made on the bearing housing but was put to one side whilst the bearings were ordered (arrived in just two days!). Hence a start being made on the saw arm using a ¼” (0.250 or 6.35mm) thick piece of flat steel.

I am happy using the DRO’s to co-ordinate the machining of parts but I still like to mark out the design to make sure I am in the right place as it were. So after marking out the arm, the rotary table was secured to the milling table and a start made in cutting the small end of the arm (photo). When it came to the larger end I had to make new clamps so the complete part of the diameter could be milled and that is where the project was left at the end of the latest session.

Tomorrow I hope to complete the arm profile and maybe the inserts and perhaps the saw head pulley. I don’t expect to spend too much time on the basic saw table, before switching to the Fowler Traction engine before going back to the pair of Seal 4 cylinder petrol engines.

I have finally decided that these are the three main projects I will concentrate on over the next couple of months and try to keep other engineering ‘distractions’ at bay. Again, time will tell……..