Member postings for brian jones 11

Can anyone suggest how to select a proper carbide tip (10mm shank) for turning gr8,8 steel on a Myford

I have struggled with ones that came with those tool sets on EB but of course I am deeply suspicious about the quality of the tips - they will cheat you if they can , its a national sport)

I found a 60deg diamond tip seemed to loose its edge quickly and I ended up with a poor cut finish on 20mm dia taking 50mu cut at 1500 rpm

These carbide tips are still a bit of a mystery to me but I couldnt touch this steel with HSS

Any advice please

Brian

Actually JB your spikey gears could have some merit

if you truncated the tops of the addenda say 5% and then run the gears together with a bit of load/speed in some abrasive flour or fluid of some sort I believe they would rapidly "run in" and settle down to be less noisy and become quasi involute

As you have the gear to make it so perhaps you could run a little trial for us to learn from

It could be quite cheap to make up a triangular tooth cutter - even a 20deg compliant one

WaM

PS

No JB  flashy animations dont do it, been there done that, you really need to be able to examine the precise motion as faces slide past each other.  Ive got that on hold while I try and get some gears made

Edited By brian jones 11 on 03/10/2021 20:51:43

Thank you John

took the word right out of my mouth

Indeed a Hob cutter has triangular straight faces which cut an involute as they turn

Will revert on this tomorrow as I try my 2:1 challenge

getting small gear blanks proved difficult without turning down much larger blanks but I have a cunning plan

I dont think Nylon blanks would cut very well do you? and you cant glue them together to make thicker blanks

OBTW for budding CADdies simulating revolving gears to examine close action at faces has baffled greatest gear minds around the world

eg the involute gears revolve by a rolling and sliding action across faces which is why clock makers favoured Cycloid teeth as they were nearly a perfect rolling action and lowest friction BUT only if they had loose axle holes

WaM

I must try and improve my microscopic photography

Sorry MEW board dumps your text at the slightest excuse so this got lost

https://www.youtube.com/watch?v=LUq33MvxqHI

ca 10.00 he is making a spur gear as he uses the vertical slide

Even with gashing his free hob method is so much quicker than gear cutting with a dividing head.

Edited By brian jones 11 on 03/10/2021 18:44:42

This Greek Blacksmith stole my idea

https://www.youtube.com/watch?v=TaMppc2LrTs

https://www.youtube.com/watch?v=103bK10WNUo

https://www.youtube.com/watch?v=LUq33MvxqHI

Not a DRO in sight, just pure skill

WaM

SOD I am working on the challenge but need to make a better tool and waiting for parts as I explained above

hold that thought

Q

Brian's DIY method is only useful when friction, distance between centres, low operating life, backlash, exact ratios, and low power transfer capability don't matter. All good if these can be ignored, otherwise free-hobbing is overly simple.

UQ

I am working on mitigating these problems Free Hobbing is Simple

There you said it SOD

Thats not fair PR the OP can object if a comment is OT. comparing the classic purist way of making gears to my rogue method is just plain "OT off topic"

I have always welcomed participation and indeed many comments have been instructional and helpful and I also fully acknowledge the shortcomings of the method

The enlightened viewer will judge the method by results and what it might do, while the bigot will get stroppy and slap me down saying "you can't do that here son , its against State Law"

WaM - off for an afternoon with Doreen

Well Gentlemachinists

An MG12 is hardly the kind of semi pro kit the home hobbyist might be expected to have in his shed

Remember why Myford took off post WWII - a 7" budget screw-cutting hobby lathe for the everyman

The DW diy vertical mill, hugely versatile which strips down into half doz manageable parts to go in a hatch back - can you do that with a Bridgeport? Doreen brought the milling world to the home hobbyist

Thank you Andrew for exemplifying my position - when does a hobbyist turn semi pro ( MEW rules as per F1 needed?) and his shed becomes a shop?

I rest my case - your Grace

WaM

Caustic commentators on this thread must remember its Title "Spur Gears - a rogue method"

If you want to pursue the conventional route on this topic by making precision standard gears then this thread is definitely not for you - it has nothing to offer that mindset, walk away.

My examination of free hobbing is more akin to blacksmithery. The Artisan didnt have equipment to drill holes, he heated up metal and punched holes (even square holes). You would hardly have described it as precision engineering but it served its purpose. Just look at the craftsmanship in a horse shoe, note square holes and wrought square nails - dont twist and loosen. These are slightly tapered so that the thin ends curl up as they are hammered into the hoof and dont fall out - thats smart.

The pursuit of free hobbing which started with using taps - (as is done in making worm gears quite successfully btw - I dont hear any howls of disagreement on that score) and extended to spur gears has been roundly discredited for many reasons clearly explained as per foregoing posts.

And I agree - it results in a non standard form

Yet more by accident and in spite of the naysayers, I managed to produce some credible meshing model gears using the method of slitting a large bolt and this tool is currently under development , waiting for parts, and is showing promise.

I am hoping that with a more precisely made gr 8.8 tool I can predict the number of teeth I will get and also the workable distance between centers.

These rogue gears will never approach the quality of precision gears made by conventional methods and they were never intended for that purpose. I expect them to function as workable gears for light duty by a DIY method available to those with limited workshops who would otherwise never considered knocking up a gear train.

So to all amateurs, hamateurs amatures, armatures, armchairs and nearly 18,000 views, lets not resort to machinist' righteous bigotry give the Blacksmith some room maybe his tool might fly

WaM

Jason I told Maureen and Doreen what you said - cocking a snook indeed on humble hobby machinists. You are off their Xmas card list. You are in the semi pro league with big machines DRO CAD CAM etc. Its not a fair comparison

No DW in my workshop or Myford for that matter,

All in hand John, I am struggling trying to fix a grinder using a 50mm x 5mm wheel so I can traveverse the slots and put a nice edge on the cutter faces. Ive figured a 5deg clearance angle by going off centre 5deg = neat

Will get there but its straining my brian

WaM

Well Sailors do like a bit of wind up dont they

For the record, I have NEVER disrespected any of the gear experts on this board nor claimed proprietorship of the free hobbing method. I simply had a box of large taps and wondered if they could be put to use

No John I havent ignored your challenge, I am just fiddling with my tool just now and how to grind it sharper. I will get onto it soonest

Well gear snobs are known for making convenient definitions so perhaps I,ll call mine KP as Kordal pitch. ~We wouldnt want to introduce any confusion into the world of gears

For me KP will be convenient and intuitive as it matches the concept of thread pitch (mm) for my tool and I hope will make an easy calc

This is after all Gears for Dummies

You should see the top of my head , its peened over

WaM

Holy Batmother are you using a DW quill as a shaping press (Doreen wouldnt like that) and the work is mounted on a rotary table? How long to chiv out each tooth? All morning jib then?

A 1 tonne Arbor press would chiv out a gear tooth in one swing of a bit of scaffold pole

As you have tickled my fancy with a Spin indexer, I fancy a 4" rotary table to mount my spare old chuck from Maureen to carry the mandrel plus fitting a digital angle gauge which has a resolution of 1 in 36000 ie 0.01deg so I could dial up what ever index I need. Way to go if needs be

I cant spare the time to construct a complete Table for 3-100 teeth that for the Armchairs

Now here is my first bash a the polygon approach to gear numbers from the example above

47 teeth OD 45mm CP 3mm. The diag shows a compliance within 130mu OD error almost negligible

IMHO it all depends on the quality of the bolt chivving and how the tool approaches the blank, ie it must engage quickly and firmly. I have to improve my mandrel - its a bit loose and must maintain tool sharpness

All this is in hand

OBTW I will be the first to admit that the method may fail for smaller diameters say <20mm 21 teeth

and a correction factor may need to be applied TBA

OBTW there are those blinded by Mistic spray who think this thread is a waste of space, well it has had over 17,000 views and 339 replies (mostly temperate) so here's cheers to the silent majority (50:1) supporting the freedom to think out of the box

WaM

BTW for the punctilious Sailors who like a wind up I might make CP - Chordal Pitch

Edited By brian jones 11 on 01/10/2021 12:45:00

I think Jasons Spin indexer (hereinafter to be known as Maureen's method) shows promise and needs more work ie mixing and matching her change wheels on a spin indexer

Cant quite get my head around the permutations maybe some lively mind can assist

here are Maureens std change wheel set

,20,21,28,30,32,33,35,39,40,43,45,48,50,51,53,55,57,60,63,64,65,70,72,75,80,81,85,90,95,100,127,,

The paste up a paper printed dial is certainly promising when used with a junior hacksaw, you then only need a shaped cutter put into Arbor bench press like this for £10

https://www.ebay.co.uk/itm/124923302943?hash=item1d1602541f:g:IxkAAOSwdXlhUsLp

Now thats fair

OBTW you can only wind up Horologists

The Armchair Dragons in the Den are just waiting to see me fall over

but I have ordered an M24 HT bolt gr 8.8 (which I believe can be case hardened) together with a jig for my angle grinder then maybe get some sharp teeth into it

As for number of teeth prediction I have a polygon calculator in mind but need to back this up with some real models  of the non ferrous kind. I found that WD40 also helped on perspex blanks. So you must bait your breath a while

Edited By brian jones 11 on 01/10/2021 05:40:59

Well yes you have indeed

You see to make a gear by conventional methods requires expensive special equipment

a) Using a universal dividing head (£250 plus set of gear cutters £125) and all morning to set up and cut a gear

b) Using a hobbing attachment need a geared universal head linked to spindle rotation £££££

c)Using a gear shape DIY type as per the Eureka design - see YT

d) Using stepper motor etc all experimental

e) CNC mega bucks

f) 3D printed - proper Prusa machine is £550 plus a year getting learning to use the machine squirting plastic thread and then taking all morning to squirt one gear - look at the example above by NW

My method has its faults as amply pointed out in a loud chorus of disapproval and its not for gear snobs - only for light duty on non ferrous mtl but it involves a mill, a large bolt with 6 suitably ground axial slots (work in progress), a mandrel to mount the gear blank and you make a gear in 5mins

It has its limitations which I am trying to address but it makes useful gears for modellers and for light duty

BTW making a proper gear is eye-wateringly complex as I have discovered on this board.

So thats the mission - gears for dummies who dont need horological perfection, maybe kids toys, robots, automatons, RC stuff, experimental stuff etc

WaM

well this board crashed and dumped my text

so I will write it up another time

suffice to say this is the result of an M24 screwed rod piece with 6 slots milled in sides to make proper cutting edges

i used a 3mm carbide end mill, it lost its edge after 6 slots ie 3 inches - is that normal for MS?

Once set up it only took 5 mins to make a gear

45mm OD 3mmCP 47 teeth

I made two mesh ok

btw

the spiral flute tap wont work cos the flute in big ca 9mm and a 6mm blank gets orphaned and loses registration

bin that

My secrete weapon worked but only gave me 2.1mm CP

it was made from a spring washer

the largest in 30mm but would need lots of eng to hold it properly and i havent got a TIG welder - shelved

I can get an M24 HT bolt gr 8.8 but would probably have to grind the slots accurately somehow using a jig

Can gr 8.8 be turned with a carbide tool on Maureen?

Well dont break open the champagn yet

This is my first run with the secret weapon

and here is the weapon naked an unabashed

I had to use a bit of plumbing to stop the leaks from my secret workshop

cost of bits for tool <£10

time to make gear 5 mins

For the armchairs here are some data

OD 44.4mm

No teeth 54

I dont think I started with the right OD so result is iffy

more work needed

Cricket bats out already

WaM

obtw I forgot to adjust the helix angle for the new CP

MK2 of tool is on drg board and may well have an adjustable CP

I need a better grinder set up to make a proper PA and cutting edge

Edited By brian jones 11 on 27/09/2021 14:10:48

Edited By brian jones 11 on 27/09/2021 14:28:28

sorry Roy I meant the 1850s

PR

Ive got IKB's biography on my Kobo and must browse (if this board stops distracting me)

A few things I remember from earlier accounts is that

a) He was a 5' short **** and invented the fashion for very tall top hats

b) He tried to push for a 7' gauge for the Bristol GWR railway arguing it provided much greater speed and stabilty but the Armchairs and the gauge wars slapped him down what a game changer that would have been

c) In Victorian times at the height of the Empire it was necessary to raise funds from investors so he became something of a fair ground showman and mountebank and not very good at budgets

d) he died young at 53 but evidence of his genius are still in use today

Kerriste PR that was his French father MIB

fascinating piece of history showing the lengths industry went devise machinery for making guns (and clocks)

There's another hour gone perusing the past

Quam tempus fuggit

WaM

BTW any Horologists here

ever get your hands on one of those pioneer Wall clocks from the 1650s, they had the dial above and a painted glass picture below. You often see them in period wild west movies

**LINK**

I could tell it was cheap and nasty just by the back of case. Mass produced, did they stamp gears out of sheet back then, they were like something in a childs toy. It didnt keep good time for long

What astonishes me JP that in this day of unbelievable high tech gadgetry at such low cost, we havent seen a means of laser scanning the gear you showed in your pic above cos thats the degree of measurement needed. Feed the data into an app and get a best estimate of what you have.

After all thats what the big boys do when making big gears, they measure to microns across a diameter of 10 meters

thats cooking on gas

Come on JB keep awake I said

DP = 1/Mod in their relevant units

Its either N/PcD Imp or PcD/N metric

If I had an equivalent sign on Qwerty I would use it

OBTW finished machining secret weapon

tomorrow is bench trials day

Heh Heh

WaM

Edited By brian jones 11 on 25/09/2021 17:49:50