Carbide toothed saw and diamond wheel tool centre - new project

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Metal Mickey

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I am not sure if this is the right heading for this new tool build but I suppose I am modifying the electric motor......forgive me if the subject area is wrong........

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 (please see photo’s) 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.

newsawtable22042009033.jpg


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.

newsawtable22042009026.jpg


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.

newsawtable22042009035.jpg


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.

newsawtable22042009003.jpg


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.

newsawtable22042009027.jpg


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.

sawtableandantifoulingleg2304200-1.jpg


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.

sawtable24042009014.jpg


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……..
 
Hi MM, Whats the width of those blades you have there?
Rob
 
Just curious, MM, are you planning to cut steel with that carbide tipped blade spinning at 5,000 rpm? I'm just wondering if that isn't way too fast...

Chuck
 
side note i use to cut steel fence post with a cicular saw when i was build fence's. it was the only lite thing i could use at the time. it worked great made a lot of noise but it worked got to really watch the kick back with steel its fast
 
RobWilson said:
Hi MM, Whats the width of those blades you have there?
Rob

I am sorry for the delay in answering your question Rob. The largest blade width is 0.112" at the carbide tip. The smallest blade has a width of 0.066" at the tip.

cfellows said:
Just curious, MM, are you planning to cut steel with that carbide tipped blade spinning at 5,000 rpm? I'm just wondering if that isn't way too fast...

Chuck

I had a practice using the milling machine and a know revolution speed and I think you have a point. So I have amended the design to allow a range of speeds so I will have some flexibility in the light of experience!

itowbig said:
side note i use to cut steel fence post with a circular saw when i was build fence's. it was the only lite thing i could use at the time. it worked great made a lot of noise but it worked got to really watch the kick back with steel its fast

I take note of your kick back comment and hopefully my intended work holding system will help...but I will take care...........
 
Hi MM thought you had gone on holiday or something ;D, Cheers for the info, Just cant read the make of the blades in the photo ?
Rob
 
RobWilson said:
Hi MM thought you had gone on holiday or something ;D, Cheers for the info, Just cant read the make of the blades in the photo ?
Rob

The large one available in the UK is SANDVIK Cormorant No.3 130mm dia with a 16mm bore and 14 teeth.
The smaller one I got from Canada via a nice model engineer.....is a Mastercraft general purpose blade and its 85mm with a 10mm bore and 24 teeth.

Hope that helps......

MM
 
Managed to get into the workshop this morning so I carried on with the saw table build. I decided that the saw blade pulley would be my area to concentrate on. It needs to be small because I don't want it to affect the maximum height of the blades and diamond stone.

I decided to go the brass route again and started by boring out the space for the bearing. Next the cut out for the rubber drive belt was made using the previously ground tool steel profiled to match the belt. When I had completed the bearing housing the pulley was reversed in the chuck and the front turned down to match the larger saw blade first. The next job was to turn down the shaft to match the smaller saw blade and diamond wheel. When coming to trial fit them though the diamond wheel is actually a few 'thou' smaller so whilst it may no be obvious to the eye in the photos the front part of the shaft is actually smaller.

The Saw holding pulley with the bearing housing bored out.....

06052009sawtablepulleys011.jpg



All the blades etc. on the pulley....but they will only be used one at a time though!!!


06052009sawtablepulleys014.jpg


The saw located in its position................

06052009sawtablepulleys016.jpg
 
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!!!

08052008sawtable017-1.jpg


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.

08052008sawtable009.jpg


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.

 
Whilst I decided before the week started that I would concentrate on the Fowler traction engine I felt I would do a little more on the saw table since I haven’t been able to spend much time recently due to health issues. The plan to move onto the Fowler was on the understanding that I would be further ahead with the saw.

However, on Wednesday I managed to complete the basic elements of the tensioning system, needed because of the adjustment I wanted to build into the design to allow the blade height and type to change. Because I am using aluminum for the body of the saw I decided to use brass wherever wear is to be expected.

The first part made was the inset that will fit on the back plate. It has two slots milled into it. One goes through and the other forms a seat for the pulley block (see photo).

13052009sawbench-tensionpulley005.jpg


To tension the belt there will be a handle which turns a threaded rod through a fixed screw block. The rod goes through the ‘T’ shaped block on which the shaft for the tension pulley sits (see photo). To allow the ‘T’ block to move in both directions I will fit 2 ‘E’ clips either side.

13052009sawbench-tensionpulley009.jpg


You can see one end has been done already. After the tension has been set the block will be secured by tightening the pulley shaft against the back plate. Whilst only two parts were made that has been a great improvement over the past couple of weeks .

Today I decided to start work on the height adjustment mechanism for the blades or diamond cutting disc. The start or which was sourcing some suitable steel to make the quadrant. I seem to be well stocked when it comes to non ferrous materials but poor for steel and the like. I eventually came upon a piece of angle iron that was just under size but would do so using the bandsaw one side was quickly removed and the remaining piece cleaned up.

To cut the radius required for the teeth the rotary table was used on the milling machine. The only cutter I have matches the Myford gear profile and will be used to create the teeth both on the saw arm and the quadrant. The radius for the quadrant was decided upon by matching a Myford gear to the profile that will fit the available space. This method has the benefit of defining the number of teeth although I will only cut 90° worth I need to have the right dividing plate on the Vertex indexing tool. In this case the divisions need to allow for 55 teeth.

The saw arm will however require only division to be found for 28 teeth (again only 90° worth will be cut). To calculate the gearing I made use of two publications namely “Model Engineer’s Handbook by Tubal Cain” (3rd Edition) and Ivan laws useful book “Gears and Gear cutting” in the Workshop Practice Series (number 17).

As a side issue I have been putting together a spreadsheet using the formula in both books for my future use covering various situations such as number of gears, their size, and number of teeth etc that can fit within a given space.

When the bugs have been ironed out I will put it on my website for downloading if anyone wants it.
The picture below shows the progress achieved in the short session I managed today.

100_2691.jpg


 
Thanks for your comment itowbig.

Today was a day of heat in the workshop. Fisrt chance for a while to get into the workshop and I took the opportunity to see if the Durafix aluminium welding system ( for more detail visit the following...)would join the two parts of the saw table together. As it turned out it did the job very well. I nervously and lightly tapped the two parts when the cooled down, gradually increasing the weight of blow until I gave up! I am confident that the parts are secured.

100_2727.jpg


Durafix aluminum welding.

I have decided that when it comes to fix the parts together that Durafix will form part of the methodology i shall use.

I then thought that since I had the kit out that I would silver solder three pins for the Fowler (two for the rear wheels) and I thought I would treat myself to a new stick of silver solder. I also got out a large tub of 'silver solder flux' bought from a local steel supplier and wished I never had! Whether it was the silver solder or the flux (or both) the normally simple job did not work well. So I have put them in the pickle solution and will see how well the solder flowed when the parts are cleaned up.


100_2728.jpg



Silver soldering but is there a problem?

The day couldn't let me have two winners could it!
 
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.

07062009sawtable003.jpg


07062009sawtable007.jpg


The next picture is a summary really of where the project is.......

07062009sawtable009.jpg
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.
 
Metal Mickey said:
The day couldn't let me have two winners could it!

I quit on winners. I quit on losers too. Makes for short days at work. :big:

Looks great!
 
Very interesting project MM nice work,looks like it will be a handy tool to have in the shop
 
Today I managed to make the basics for the mechanism to adjust the blade/grinding wheel height. It consists of a bracket with a slot in it that holds the brass adjusting wheel. This bracket will be secured to the back plate of the saw table and because the wheel is trapped between the forks of the bracket by turning the knurled wheel the studding will advance or retract accordingly. Below are some photos......

Not exactly CAD eh!

08062009sawtablebladeadjuster003.jpg


The basic idea can be seen here. Only the linkage to resolve.

08062009sawtablebladeadjuster007.jpg



What remains to be sorted out is a linkage between the end of the studding and the fulcrum lever.Since the fulcrum lever moves at an angle to the vertical position, this will not allow a direct fixing method to the studding. So either I make a pin in the upright with a slot in the fulcrum arm allowing the pin to slide, or a linkage not locked at either end, has yet to be decided. I will make up some drawings tonight (as per last nights bracket design) before making up the part(s) in the next session.

Don't take too much notice of the finish because it will be 'blinged' up towards the end.

 
Mike,

Your Crap-O-Cad is much neater than mine. :bow:

Looking at what you have drawn, I believe a slot in the bell crank/fulcrum arm may be the better solution.

Hope this helps. ???

Best Regards
Bob
 
Hello Bob, great minds and al that. I have made a linkage that works but it looks horrible so I will be taking dimensions and remaking the whole toothed fulcrum arm based on the 'lash up'

Didn't manage to get to the workshop today so maybe tomorrow. I'll post pictures then.

Mike
 
Mickey,

From what I can see, you're mounting the blade on a brass arbour. If the blade slips under load (and brass can be a bit slippery), it's likely that the hole in the blade will chew into the brass, damaging it and allowing the blade to run eccentric.

I've just rebuilt a Startrite table saw, and made a new spindle. The original had a 5/8" spindle, most modern 12" blades have a 30mm hole. Rather than harden the 30mm section of the spindle, I pressed the inner race of a needle roller bearing onto it. 30mm od, 25mm bore, ground and as hard as hell. It fits the bore of the blades perfectly.

Not sure if this would work in your application, but it's a thought.

Regards,

Ian
 

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