Thread: Sussing out a new project

You would start with a round hole 17/32" dia,and then Broach.
Other allternative would be to start with the same size hole and file.

The W&B has a blind end as apposed to a though hole, can you use some type of broach for blind holes

Hi GC,

Do you have a dwg you could post? I had one years ago when I made a torque wrench at Tech school, it was also based on the W&B unit. Dwg is long gone together my youth.

I agree, it would make a terrific project for students, and some of us oldies.

Ken

Hi guys ,
No plans as yet
This torque wrench project its something I am researching.I have heard of the plans on the ANTA site,through another teacher,probably the same ones as Ken is referring to.

I am doing my homework needed for planning ahead for 2011. I am a one man band and if I have to commit part of my precious and hard won budget to this project I need to know if its feasible and achievable by most of the cherubs.

I am putting in a big effort on it as I am competing against technology from Ipods ,mobile phones,cars and girls.If something does not interest these kids its dead in the water,so I have to come up with something that grabs them.

My background is that of a pressure welder who has workshop exposure but not "on the machine experience", hence there's gaps in my my knowledge.
I am told there's a steel called Vibrac En25 for the torsion arm and the rest is mild steel though I am thinking along the lines of CRS for some of the parts.

I am familiar with the W &B torque wrench owning one that's lent out at the moment. I had planned to reverse engineer a lot of components just by measuring and recording the specs.
There's stuff like engraving the torque scale and calibrating details to be sorted yet.I have some experiments with the mill as I think that's what I will use to scratch engrave the linear scale.

The W &B torque wrench design itself must be pretty good as I have read that it has had no change for 20 or thirty years.

If I get my ducks in a row and find it can be done I shall post details but this will be months away.

At the moment I am getting as much input and info from all sources, as I can get my hands on.

Grahame

Theres a lot of work in doing this properly. It used to be one of the stage 3 Fitting and Machining projects at TAFE. It might be a bit ambitious for school kids.
From memory the square hole in the W&B wrench is not a blind hole. The flat arm that holds the indicator pin covers one end of the hole.

A good basic project that would be suited to the kids is an engineers clamp. You can decide how much work you want them to do on it. ie if you want them to do a bit of filing you could start them of with black square bar and they have to file it flat, smooth and square. Or you could start off with bright square bar and they wouldn't have as much filing to do.

regards
Bollie7

Hi Grahame
Congratulations for attempting this project. Maybe the Warren and Brown may be a little ambitious, however I have another similar unit in my shed which works reasonably well and easier to make. I am off on a short holiday at the moment, however when I return I will photograph and post the pics. I will; also give some thought as to manufacturing methods and materials.
Ray
P.S If I should forget to follow this up in the next couple weeks can someone please wake me up

Originally Posted by China

W&B has a blind end as apposed to a though hole, can you use some type of broach for blind holes

Hi I would drill the hole through the material then broach or file the square, as for the blind hole dont forget that the flat bar with the sring loaded click sits over the top of the square hole. If the depth of the square drive hole is to deeper than you want - Simply machine or bore a hole bigger than the square on the oppersite side of the material then bore to remove the excess excess material, till the square drive hole is at the depth that you want. Then make a steel plug of the same size. You could put a couple of weld tacks on it but I really would not bother as the flat bar will hold it in place.

Cheers Warren

why not just have a male drive...... why does it need to be female?
how often does one need to remove the male adapter....if you use a ratchet drive or speed brace you need differnt adapters if you need to use larger/smaller sockets

Grahame,
The torque wrench is a great idea, emphasise to the cherubs with automotive interests how vital a torque wrench is when working on their cars to spark their interest.
I made one at tech school in year 11 back in the eighties and used it for quite a few years until I got a fancier one, still use a W&B 3/4 inch version.
My old one is lying around the shed somwhere and if you like I can dig it out and take some measurements for you.
We used metal stamps to mark the graduations but engraving would be much nicer.
The square drive needs to be a through hole so you can torque left hand threads.
I still remember broaching mine and being amazed that simply forcing a piece of steel through a drilled hole could actually cut a square hole.
Cheers,
Greg.

Originally Posted by bollie7

From memory the square hole in the W&B wrench is not a blind hole. The flat arm that holds the indicator pin covers one end of the hole.

Correct.

Nev

You've heard of a square hole drill based on a Reuleaux triangle mounted in a special drill bit holder attached to your drill press? : [ame="http://http//www.youtube.com/watch?v=Iz3pDMP7IsE&feature=related"]http://www.youtube.com/watch?v=Iz3pDMP7IsE&feature=related[/ame]

Good idea, but I wonder how hard it is on the drill bearings? Might be OK in a mill.

Dave

Originally Posted by Dave J

Good idea, but I wonder how hard it is on the drill bearings? Might be OK in a mill.

Dave

The square hole drill does have a special holder to allow the lateral cam-like motion that the drill spindle drives, so it's not like it's trying to bend the drill spindle as it traces it's motion. They are an old, proven technology, if they caused bearing failures you'd think it would have been apparent by now. Also like a drill it's only taking small bites at a time as it gets fed through the square starter hole, it may look like he's trying to square up the entire hole at first glance.

I suspect something like this may be expensive to buy new but Ebay UK seems to have tooling like this pop up from time to time.

How about laser etching the torque scale? Obviously this is something which would have to be farmed out but the kids could have some input into this.

The beauty of this is the scale can be drawn up in Autocad (or the like) and the dxf file can be sent to the laser cutter and etched onto the material at 1:1 scale.

Smaller plates could be etched with the scale, cut to size (perhaps with a radius on each corner?) and attached to the wrench in the appropriate location with rivets or small screws. These could be made from #4 stainless steel and would look classy. The plates can have the rivet holes cut and cut out of the sheet at the same time as the etching.

Any reputable laser cutting business should be able to achieve this. I work for a laser cutter in Melbourne and we have done similar things before, but I am sure you could find one in your neck of the woods.

On the up side it will give the kids an intro to CAD/CAM programming and modern manufacturing techniques. On the downside it removes the learning experience from the workshop of doing it the 'old fashioned way' and could be a little pricey for small batches, although I can't see how you would pay much more than $5.00 each for a batch of 20.