Member postings for I.M. OUTAHERE

Thats is what Les is talking about by picking up a signal from the points .

I was just thinking about how a micron data logger picked up its rpm signal on a junior dragster , it is just a piece of wire wrapped around the plug end of the HT wire , this is used to give an inductive pick up for the tacho .

Plenty of ways to clean up the signal , schmitt trigger rings a bell but i'm sure someone will know better than i !

We forgive you Neil !

Nidy ,

You forgot the most important temperature scale of all time - PTBC - Pyrometerus temperus Beerus Correctus !

Is the output of a generator or alternator purely linear in relation to the rpm ? Probably not .

I think Les has hit the nail on the head , you could also use an inductive pick up off the coil lead to drive it either way a wire is easy to hide , the only glitch i see is scaling and this would depend on how accurate you want the tacho to be .

With such a car wouldn't you want the least conspicuous fit out ? Does it have a generator on it ? If so does the generator have a cooling fan or impeller ? If yes could you use a proximity sensor to pick up the fan / impeller blades ?

I wonder how one would go using a micro to convert a voltage derived from a frequency to voltage converter to a pwm and drive the meter from that ? May help to make the meter reading track the rpm better .

Edited By XD 351 on 10/08/2018 10:32:25

Could also be a printing issue and once it has gone to print the Editor has no control.

Unlike some magazines they don't have a team of proof readers so occasionally errors slip through and it is the same with many , many other publications !

There is a  recent video on the great scott channel  on youtube where  he tested the efficiency of , stepper, brushless and brushed motors as generators .

Tried to embed the video here but was couldn't get it to work , i will have to search on the forum as im sure the answer is there .

Edited By XD 351 on 10/08/2018 09:21:22

Edited By XD 351 on 10/08/2018 09:22:24

The only thing i could find was a 3/8 flare fitting that has a cone angle of 90 deg included so maybe chuck up some scrap alloy and cut a 45 deg chamfer then use it to check the angle by putting some blue or sharpie on the seat and lap them together , if it smears most of the ink on the seat i think it will be close enough .

Another thought i had ( yes it is true that you only need two brain cells to think! ) is to use a single pulse generator feeding two identical steppers so in theory they should be rotating at the same speed . One drives the hob the other drives the gear blank but the gear blank mandrel is not directly driven like the hob spindle is .

The gear blank mandrel is driven by a worm wheel that is the same diameter and pitch as the hob and this is driving a gear which is the same tooth count and diameter as the gear to be cut . This should give the correct drive ratio required to cut the gear and the dummy gear and worm wheel would be drawn up in cad then 3D printed , once the hob has cut deep enough to free hob the drive system on the gear mandrel could be disengaged if needed .

Once again just a thought !

And supplied some obscure theory written two centuries ago to back it up !

Wouldn't just be a matter of dividing the spindle speed by the number of teeth to be cut on the gear blank ? Isn't a hob is basically a thread with cutting teeth gashed into it ? If so one turn advances what ever it is engaged with by one pitch or in the case of a hob one tooth , if the spindle is rotating at 250 rpm and we are cutting a 25 tooth gear the gear blank would be rotating at 10 rpm to match the hob .

What if the spindle was driven by a stepper motor & controller that is driven by a square wave generator ( crystal controlled ? ) couldn't the gear blank drive be exactly the same set up and use the same square wave signal that is controlling the spindle but fed through a microcontroller to do the frequency division then fed to the gear blank drive stepper controller and motor ? Or would the gear blank drive be better served if its square wave drive was generated by the encoder on the hob spindle ? That way it would sort of be able to sense the speed of the spindle and any variation because of the load when cutting .

Just some thoughts !

For my mill and lathe i use some cheap spray on engine degreaser applied to a rag or paper towel . This stuff always pops up on special at a few of my local auto stores and i buy it by the box full spray cans of the stuff .

I have used Nappa leather used to cover the bed , it was held in place with magnets and tends to drape down in the bed vally forming a pocket and scrunches up well - i got the idea from Stefan gotteswinter off his youtube channel i never had much luck with paper - always seemed to tear where you don't want it to .. You can also stuff a piece of foam in the chuck bore to keep the chips out of the inside of the chuck bore - a nerf ball works well for this . If you don't mind the noise the vacuum cleaner trick works well but as i have a wall mounted unit walking over to switch it on/ off is a pia ! I do have an old houshold unit around here somewhere that i may press into service next time i machine some cast iron .

My mill is basically the same as a chester lux with the crank handle on the side of the column , i origianally used an 18 volt drill but ended up just buying a dirt cheap mains power drill with the built in speed control and using it to raise ./ lower the head. I can buy the proper motor / gearbox unit for this but the price was unbelievable !

It depends on how much torque you need to turn the handle ,if it is easily turned then a big stepper motoer will do it If you want finer control . The other issue i found using DC motors is they can draw a lot of current and getting a power supply that can handle 40 or 50 amps + wasn't easy or cheap !

Thanks Jason!

https://youtu.be/ZhICrb0Tbn4

Doesn't give any plans but does show his general set up and software he is using .

Edited By JasonB on 07/08/2018 19:08:47

Has anyone come across a reference chart for making broach bushes ? It would be nice to be able to look up the dimensions of the slot required for each size broach and not have to fiddle around measuring the broach everytime i need to make a bush , this would also give you the thickness of the shim ( if needed ) . I think i remember seeing on by minuteman but it was for imperial sized broaches , i also use metric .

As far as i can see 90 % of all briggs motors are made in the USA , only the vangaurd horizontal 2 & 3 cyl water cooled engines are made outside of the U.S and they are assembled in japan using U.S made parts .

They now own the Australian icon of mowers - Victa and i believe they are assembled in Australia using imported and local parts . Victa used to owned by Sunbeam years ago .

I don't recall anything about it being a one off sort of thing when i signed up for start up this is free for (i think ) 1 year but you can re sign at the end of that period for another year and so on .

Also check that the table surface is ground flat , sit your parallel on it and shine a light behind to see if there any gaps

Same here and the closest i got to anything that uses any of the numbers was 0405 which is a hex inverter.

I find it hard to believe that the chip just died , usually it is because something else has gone wrong and killed it .

It could just come down to a crook keypad or a bad connection somewhere

The only other option i see is to try and contact the manufacturer and see if a replacemnt board is available other than that it may be a bin job .

I use a step drill as it only has one cutting edge it wont't dig in