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Small spline broach manufacture

plunger

Aluminum
Joined
Nov 12, 2010
Location
s africa
I hope someone can point me in the right direction.I am a plumber by trade and often get asked to make extensions for our undertile stoptaps for a shower.We dont have wooden houses here in Darkest South Africa and sometimes the faucets are embedded into the wall to deep bythe plumber. When its timeto put the handles on they are not able to fit.
How will I make a splined broach to make a male and female extension piece like in the pic.?
To give an idea of size the splined OD is about 7,7mm and there are 20 splines in total.
spline.jpg
 
Hi plunger:
I assume you want a broach to make these for your own customers and not to corner the world market on faucet extensions...is that correct?
Do you need to be able to broach both the male and the female spline or can you make the male spline by milling it directly on the brass part?
Are you hoping to rotary broach the female spline or push broach it?

Traditionally these tools were made by grinding them from a solid bar of High Speed Steel on a tool and cutter grinder or on a surface grinder with a profile dressed grinding wheel and an indexer to index the blank.
It is also possible to make these kinds of shapes with a wire EDM and then mounting them into a holder.
It is also possible to make them by wire EDM cutting an electrode and then reverse burning them using a sinker EDM.

In your case, without having any of those toys, the best way forward is to mill a broach blank from A-2 or D-2 tool steel and harden it.
Of course this assumes you have a milling machine and an indexer.

You make a fly cutter with the proper tooth space profile on it and then you index it around your tool steel blank, milling your profile with sufficient back daft that it doesn't bind when you push it in the hole.
You can broach thousands of brass parts with a tool like this , and if you don't make the back draft more than a few tenths per inch, you can sharpen it easily by grinding the face.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining
 
If you build a push broach you will have to be able to push completely through you part. Make a coupler so to speak and the spline both sides of your extension. The spline could be made tight on the end you push onto the valve to hold it. It would have to be fairly long to broach that length. A rotary broach is going to take a good amount of force to cut that spline but with the use you could open up the id to relieve some pressure required. Ive made both for my own use not bad to do like Implmex said to do


When I find it I don’t need it
When I need it I can’t find it!
 
Unless it's a one-off for a single job, find someone with a #7 Fellows to make you a bunch. Make 50 or 100 of the things and sell them, it'll be a lot less grief and you can make a few bucks. Gear shaper will cut those in less than five minutes, it'd take you an hour each by hand. And they are small enough so if you had to, could ship even internationally.
 
It is one of those things that is hard to judge how many you need . Quantities will be only when someone makes a stuff up. So they either chop the wall and repipe and patch and retile or buy an adapter.
Buying a rotary broach with our Rand Dollar exchange is painful ,plus the chance of it getting lost in shipping and possibly not fitting is risky.
Quantities will be very low .Rotary broaching would be nice though.
 
Unless it's a one-off for a single job, find someone with a #7 Fellows to make you a bunch. Make 50 or 100 of the things and sell them, it'll be a lot less grief and you can make a few bucks. Gear shaper will cut those in less than five minutes, it'd take you an hour each by hand. And they are small enough so if you had to, could ship even internationally.

To make these on a gearshaper will be too costly . But now could a guy with a gearshaper not make me a broach.?The spline is like a gear in away.But can a machine like this make such a small spline broach. The OD is only 7,7mm.Is it likely gear companies would ever get a call to make such a small gear.
 
$8 is too much to risk ? Maybe a lemonade stand would be a better business for you ?

I dont like lemonade. Have you seen where I live. It isnt 8 dollars . Its R128 which excludes shipping plus the chance it gets lost (very good chance)and taxes . Then it might not fit . I want to make this myself and have control of it myself to take guesswork out the equation.
 
Hi plunger:
I assume you want a broach to make these for your own customers and not to corner the world market on faucet extensions...is that correct?
Do you need to be able to broach both the male and the female spline or can you make the male spline by milling it directly on the brass part?
Are you hoping to rotary broach the female spline or push broach it?

Traditionally these tools were made by grinding them from a solid bar of High Speed Steel on a tool and cutter grinder or on a surface grinder with a profile dressed grinding wheel and an indexer to index the blank.
It is also possible to make these kinds of shapes with a wire EDM and then mounting them into a holder.
It is also possible to make them by wire EDM cutting an electrode and then reverse burning them using a sinker EDM.

In your case, without having any of those toys, the best way forward is to mill a broach blank from A-2 or D-2 tool steel and harden it.
Of course this assumes you have a milling machine and an indexer.

You make a fly cutter with the proper tooth space profile on it and then you index it around your tool steel blank, milling your profile with sufficient back daft that it doesn't bind when you push it in the hole.
You can broach thousands of brass parts with a tool like this , and if you don't make the back draft more than a few tenths per inch, you can sharpen it easily by grinding the face.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

Marcus remember I am a plumber so dont fully understand the available technology out there. So if I say something silly please forgive me. Could this whole setup be made by wirecutting. Can wirecutting do such small profiles . I understand wirecutting can make the female broach but how would it make the male broach. ?I will need to make a male,female extension and being a blind hole the broach will be limited in its stroke.
If I made a male part in copper or graphite and gave it too a company that does spark eroding could they burn a broach into a piece of hardened steel which would then become the female broach.?Can wire eroding cut the male broach and if it can be pinned to a holding tool would that work. ?
Not having the ability to CAD draw and having the ability to measure the angles and profiles accurately its hard to know exactly what the angles and profile is.

I made broach out of silver steel by making an indexing plate on the back of my emco v13 lathe using a 100 tooth gear and using a racking tool I made by converting my top slide . It worked but I would like to get it more user friendly .Its difficult to harden metal with fine detail using an oxy set in a home shop environment.

If I can get this made by EDM does it mean I can eliminate the hardening process or does EDM also struggle with tool steel in its hardened state.
I can get this hardened by a professional company.
Thanks for your assistance .
 
how about just soft soldering the extension on with no internal spline?

It needs to be user friendly and simple . You must remember some homeowners sitting with this problem will have no idea how to soft solder. The problem with that as well is on some faucets it would be a problem getting the trim set off if you need to change a washer.
 
This happens in Hong Kong, too.

One buys the "stem extender" from the valve maker. Go ogle "stem extension" or "stem extender" and the valve maker's name, find this sort of goods:

Amazon.com : kohler stem extension

Stock item. No need to roll yer own. You were not the first person ever to have a need.

If no joy?

We simply demo the 'crete. Grout in a stainless bowl as resembles a flat-bottom ash tray with a hole in it at the proper depth. Tile & trim as needed

Now your operating handle may be a skosh recessed.

BFD. It's all stock parts.

And you don't need any magical resource but basic 'crete & tile savvy. Which is dead-easy to find, given the Chinese regard concrete as no more enduring than aged do fu. They seem to birth kids with a demo-hammer already growing out of their arm?

It's a living... Given how much of their shiddy 'crete was mixed with sea-water, they are accustomed to re-do in a New York Minute.

:(

No one makes this in South Africa. I am not trying to re invent the wheel. Buying premade extensions overseas is out of the question. Even the local tap manufacturer who has been in business doesnt make extensions for these faucets. And they make a bloody good quality product. Unfortunately they have closed their local production plant down after being in business for 60 years and their stuff is now made in China.

I am really trying to just find how to go about making these broaches ,not how to shop online at Amazon and ebay because they dont deliver to S Africa.
If I can buy a pre built rotary broach and I know it will work I would consider that. Hopefully a bought broach will work in my home made rotary broach because I dont think you realize how costly things are here in S Africa.
 
It needs to be user friendly and simple . You must remember some homeowners sitting with this problem will have no idea how to soft solder. The problem with that as well is on some faucets it would be a problem getting the trim set off if you need to change a washer.

I don't get it. Who is the customer? If this is for the homeowner to apply, then sell them an extended faucet stem, already soldered on. If it is for a plumber to apply then sell them an extension kit with multiple adaptor extensions so they can apply at point of fitting. No problem to change the washer, but if the faucet stem needs replacing they will have to buy a new stem assembly, so double bonus to you.
 
There is another part to this extension. Its to accommodate the trim set.Now this varies according to the style of faucet.
There must be a gazilion different splines shafts. 16 teeth 20 teeth twenty two teeth and then different sizes as well. In S Africa most headparts use the twenty tooth ,7,7 mm OD. It seems less popular overseas. I appreciate the help but cant you just teach me how to make a broach rather than try to teach me to be a good businessman.I am never going to be good businessmen.
This is what I get asked to make. It will be small quantities. But when you get this problem it is far cheaper to use an extension rather than chop tiles and redo.
broach 1.jpg
broachh2.jpg
This is the attempt at making it myself. It works but I like making good stuff and it can be better. You can see the male broach on the left and the female broach I made on the far right. So my question is can the female broach be successfully wire cut in harden steel and can wire cutting make a male broach . There was a company specializing in making different end mills etc but I cant get hold of them. Its possible they were effected by our July riots which as you know were the worlds largest riot ever. So they may have been burnt down.
 
Since you are a plumber rather than a machinist I suggest you try and find a shop in your area that can make these in batches.

Update: My apologies to plunger.

I posted without reading through the whole thread and didn't realize he had already made a broach and extensions. Since you do indeed have the skills I suggest that instead of using the lathe to broach the teeth you make a simple hand shaper and indexing fixture so cutting the splines will be quicker. Plenty of plans on the internet but basically similar to a tailstock with a lever instead of a screw.
 
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Since you are a plumber rather than a machinist I suggest you try and find a shop in your area that can make these in batches.

Yes I am a qualified plumber but was a qualified tool ,jig and die maker thirty years ago. I have a pretty well equipped workshop and use a cnc shop down the road for repeat jobs.My niche is making obsolete parts and solving plumbing problems for the industry.
In terms of machining I wont deny Im a hacker and learn something new every day. I wasnt in the trade long enough to get skilled at it. But thats really besides the point .My question here was how to go about making a broach for this application. Either by making it myself or getting someone to make it for me. But I thought the idea of a forum like this is to learn and share ideas.

Thats why Im here.
 
I am starting to wonder if I need to be patient and wait for more advice .Or if you guys just dont know how yourselves.The tool I made works and works properly but is a ball ache to set up. I have to smack the female broach off and have made a stripper plate to get the male out. I never allowed any relief for this and stayed clear of trying the rotary broach style simply because at that stage I never made myself a rotary broach.
I am not going to deny I am bad at maths and clueless at drawing so if anyone here can suggest how to measure such a small broach I would be interested to hear how.?
As I said I made these broaches on a lathe by racking it .I am tempted to try this in my milling machine using a dividing head this time but am not sure how to make the cutting tool. ? Do I make a single point flycutter or should I perhaps make a cutter on the lathe and then slit it similer to the flutes in a tap.

Come on guys show some Good old american hospitality. Not sny remarks like go make lemonade. :)This is a site the whole world looks at.If you asked this on a S African forum people would fall over each other trying to help you.We are quite a friendly bunch.Implmex seemed to know how to go about this.
 
Hi again plunger:
You wrote:
Marcus remember I am a plumber so dont fully understand the available technology out there. So if I say something silly please forgive me. Could this whole setup be made by wirecutting. Can wirecutting do such small profiles . I understand wirecutting can make the female broach but how would it make the male broach. ?I will need to make a male,female extension and being a blind hole the broach will be limited in its stroke.
If I made a male part in copper or graphite and gave it too a company that does spark eroding could they burn a broach into a piece of hardened steel which would then become the female broach.?Can wire eroding cut the male broach and if it can be pinned to a holding tool would that work. ?
Not having the ability to CAD draw and having the ability to measure the angles and profiles accurately its hard to know exactly what the angles and profile is.

I made broach out of silver steel by making an indexing plate on the back of my emco v13 lathe using a 100 tooth gear and using a racking tool I made by converting my top slide . It worked but I would like to get it more user friendly .Its difficult to harden metal with fine detail using an oxy set in a home shop environment.

If I can get this made by EDM does it mean I can eliminate the hardening process or does EDM also struggle with tool steel in its hardened state.
I can get this hardened by a professional company.
Thanks for your assistance .


So to answer some of your questions:
Yes wirecutting can make extremely small things and this broach (both male and female) is well within its capabilities.
The only thing is that the wire has a certain diameter, 0.25mm is the most common size and this will leave a radius on every internal corner.
It will be a bit bigger than 0.125 mm.
Although it's an academic question for your circumstances (wire work is very expensive...you'll spend at least ten times what you would do to have it shaped on a gear shaper), the male broach is made by wire cutting most of the way around the profile on a slight taper, leaving a tab so it can be skim cut to precise dimensions (VERY precise dimensions...within microns), then it is chopped free of the stock with the wire, a holder is wire cut precisely so the almost finished punch can be dropped into it and then the tab is trimmed to blend perfectly into the rest of the contour.
Last a slightly smaller broach holder is wire cut on the same taper and the tapered broach is dropped in with Loctite to hold it so the business end is sticking out.
It can be cross pinned or a setscrew can be run in so it's held in tightly against the withdrawing force when it is being pulled back out of a broached hole.

A female form is much simpler to make...a start hole through your block is all you need and you just keep running around the profile until it is the size and surface finish you need.

Reverse burning on a sinker EDM involves wire cutting a copper or graphite female shape then dropping it over a punch blank to burn the male punch.
Below is a picture of a punch made this way.
Again, it's kind of an academic dissertation; no way can you justify all the expense of doing it this way, and you've expressed a desire to roll your own rather than taking it to an outside source to have it made.
BTW, yes these processes work just fine on hardened steel...EDM doesn't even notice the steel is hard.

With regard to what you CAN do at home in a decently equipped shop...you've found a way to make a decent male broach on your lathe, so a thing to consider changing is the steel you make it from.
The ones I recommended above (A-2 or D-2) are "air hardening" steels often used to make punch dies.
Both need to be professionally hardened to get properly hard and properly tough, but they will produce a tougher, longer lasting punch and because they both quench in air, the details will be better preserved and there will be much less distortion.

However, silver steel (W-1) properly handled will also produce a perfectly acceptable punch for broaching brass.
You need to do better than cooking it with the torch till it's kinda red and then tossing it in a bucket of water or motor oil.

The best way forward is to have it professionally hardened.
The next best way is to buy a little temperature controlled kiln and some foil wrap to shield it from excessive oxidation when it's heated.

The third best way, and the one most appropriate for you if you want to do it yourself with what you have is to put your broach into a short section of close fitting iron pipe with end caps. cook the whole works with the torch until a magnet won't stick to the pipe anymore, heat soak it for a bit at that temperature, and then quench the whole works in a super fast quench like brine.
You MUST have a close fit between the pipe and the punch...silver steel needs a fast quench to harden properly so you want heat transfer through the pipe and an air gap slows the quench down.
You can also pack the pipe with spent (cooked) cast iron chips to help with the heat transfer.
You can also try to fake it with A-2 this way...A-2 is air hardening so you just need to get it hot enough for long enough and then you can just let it cool in still air.
It won't be as good as the steel is capable of but it will still be pretty good.

Another way forward with the quench is to use an old blacksmith's trick for making edged tools and that is to heat to the critical temperature, then quench only the business end, descale it quickly while the shank is still hot and watch the tempering colours run until correct then quench again, descale again , watch the colours again and then do a final full quench in warm oil.
This gives you a graded hardness and toughness from the business end into the shank...perfect for your needs.

To make a female broach; the traditional way of course is to make a male first, harden it, and then force it through a soft female blank with a hole in it, then harden the female.
Depending on the size and number of the teeth it may take a huge amount of force...more than you can generate in a typical home shop and more than a silver steel punch can take.
If you don't have a press and don't want to risk pulverizing your beautiful, just made punch, the traditional way is to drill a hole in your blank, bore it to minor diameter then rig a single point shaper tool and shape it tooth by tooth just like you did for the male.
It's laborious, it's a pain in the ass, but you only have to do it once, it takes only gear you already have (plus a little creativity), and it works.

So that's it in a nutshell...have a look at the reverse burned punch picture below just for fun, and go to town with what you have.
Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com
 

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