Chris's Holly Pumping Engine Build

[crueby]

Side project, maybe....

One thing that I've been wanting for a long time is a much smaller ratchet handle. I've got a set of Wiha tool bits with sockets/torx/hex/etc bits, all with a 4mm hex base. The handles for it are very good, but there are times that I need to get in between other parts and a ratchet handle would be the way to go. I found a smallish ratchet meant for headlight adjusting on Fords, that I was able to adapt to take the 4mm hex shanks. Works quite well, but is still a bit large. Decided to see what I could draw up in Fusion, and with a little fiddling came up with this as a start:


Like other small ratchets, a reversing lever would add size, so it would be used to drive with the bit on one side, remove with the bit on the other. The center cylinder with the hex opening would be made by adapting the 4mm driver from the Wiha set (spares can be bought seperately). For scale, the grid behind it is a 1" major grid size with 10 smaller grids per inch, so the end section is .31" by .4", cover held with a 2-56 screw.

In looking back at it, one thing I'm going to change is increase the number of teeth on the ratchet wheel, as drawn its only 8, which means a 45 degree 'click' minimum, and smaller angle would be better. That might make the width a little smaller too... I've got pieces of clock spring sheets that could be used on the pawl.

Spot anything else I am missing? Looks makeable - some bits of 303 stainless would work well.

Might actually make this - if it works I'll post the drawings for everyone.
Chris

[RReid]

That looks like a pretty slick idea, and should be a very useful tool if you go forward with it. I hope you do build it and post drawings, I'd be inclined to build one.

[Dave Otto]

Hi Chris

I have a set like this at work and also one at home. It is similar to your proposed design except it uses a spline on each tool to engage the pawl.
https://www.newmantools.com/wfmc.htm


Dave

[cnr6400]

Nice tooling ideas! If you knew anyone with a wire EDM machine you could make the pawl and a curved spring, for even more compact design, in one piece out of a piece of pre-hardened gauge plate. (if it's worth doing, it's worth OVER doing!)   

[crueby]

Hi Chris

I have a set like this at work and also one at home. It is similar to your proposed design except it uses a spline on each tool to engage the pawl.
https://www.newmantools.com/wfmc.htm


Dave

Nice setup- how big is the ratchet head?

[crueby]

Been searching around, found some other ratchet designs that would be a lot finer resolution and still small... More tomorrow.

[crueby]

More playing around with the ratchet design - fun to do. I've changed the gear and ratchet pawl setup, got it to be reversing with 16 teeth in the same size, body is a little shallower but the reverse lever adds back some height. The end screw on the lever can drop into detents in the cover to hold it in place - slack in the screw holes will give it room to do so. I chose the gear tooth shape so I can cut them with the end corner of an end mill, no special cutter needed. The hex socket I can cut from the extension bar made for the Wiha tools, the hex opening is 4mm, their bits are nice and small, makes the unit much smaller than a standard 1/4" drive ratchet.


Should be an easy build - will likely make up the prototype between crankshaft parts.
Speaking of crankshaft parts, I've gotten a start on profiling the end crank webs, pics on that later...

[Dave Otto]

Hi Chris

I have a set like this at work and also one at home. It is similar to your proposed design except it uses a spline on each tool to engage the pawl.
https://www.newmantools.com/wfmc.htm


Dave

Nice setup- how big is the ratchet head?

It is .428" wide and .455" tall, the square part of the head is about 1.2" long.

Dave

[crueby]

Hi Chris

I have a set like this at work and also one at home. It is similar to your proposed design except it uses a spline on each tool to engage the pawl.
https://www.newmantools.com/wfmc.htm


Dave

Nice setup- how big is the ratchet head?

It is .428" wide and .455" tall, the square part of the head is about 1.2" long.

Dave

Great, thanks!

[Dave Otto]

It does have a pretty stiff spring, so might not work real well is a situation where the fastener does not have much resistance and you can't get a finger on it to add some.

Dave

[crueby]

It does have a pretty stiff spring, so might not work real well is a situation where the fastener does not have much resistance and you can't get a finger on it to add some.

Dave

Good to know. Since I already have the big set of Wiha bits, I think I'll just go ahead and try making my own small one. The design I've got is about the same width, just a bit shallower, than that one. I've got several thicknesses of clock spring material (pendulum suspension spring too, which is thinner), will try different thicknesses and see what works best. I had not thought of being able to spin the bit by hand for starting screws, good idea!

[crueby]

Some really good progress on the end crank webs. To bore the large hole at the crank end of each, I drilled/bored them on the lathe rather than with the boring head on the mill - it went a lot faster this way without having to stop between passes to increase the throw on the boring head. It just took a little extra measurement to get the offset correct for the small hole on the mill, but overall a lot faster.

The placement of the small hole for the crank pin is important, so that was done on the mill. The bars were left a little long before boring the holes, so the first hole just had to be close-ish.


Both webs (HP and LP cylinders) bored and the outlines sketched on as a double-check when setting up.


The sides were taken down first - used a pair of drill shanks in the holes and on top of the vise to set the angle consistantly.

Then set up the rotary table and tooling plate on the mill - screwed a small piece of stock turned to the size of the bore in the center hole of the tooling plate to position the webs. Parts were clamped down with some card stock underneath so the end mill could be set just above the tooling plate.

After doing both large ends, the alignment pin was replaced with a smaller one sized for the crank pin holes, and the webs clamped on again one at a time.

and rounded those ends over as well...

Next to last shaping step was back on the lathe, turning the crank pin ends down to thickness, leaving a boss at the shaft end.

One turned down so far, one to go. Then the last shaping is to thin the boss down to final thickness, the parts were cut from 1/2" thick bar, the part is a little thinner than that.

[RReid]

A great sequence and a very "cranky" looking result! 

[cnr6400]

 

[crueby]

Thanks guys!  Just finished taking the second web down. Test fitting again showed that the steel bar did move just a hair, the previously round shaft holes went just a little bit oblong along the length of the web, as the rolling stresses from when they made the bar came into play as the sides were machined away. Not much, just enough to bind what was a close sliding fit as they slid on the shaft, needed a little filing to correct so all is well again. Would have been better to finish the hopes last, but would have been harder to hold on the mill. Next time I will hopefully remember that!