Author Topic: By Jupiter  (Read 40103 times)

Offline Vixen

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Re: By Jupiter
« Reply #300 on: May 02, 2019, 03:08:10 PM »
Jason, Roger, Mike

Thanks for your input and encouragement. Sometimes we all need a boost from others.

It's encouraging to hear that Jason does tapered keyways in much the same way as I tried. i.e tapered guide, drill press and no tilting of the workpiece. The only difference being cast iron vs mild steel.  Unfortunately I am forced to remove some of the teeth to clear the cone seating at the front of the hub. However I can leave more of the land below the ground off teeth to act as a guide or sole.

From what Jason and Roger say, every effort must be made to stop the first tooth or two from tilting and digging in. Now that I am aware of this real and present danger, I can be on my guard and take steps to stop a dig in, because once a dig in occures you have little option but to push that oversize chip all the way through.

Mike, Thanks for the suggestion to use the CNC mill as a slotting head, I had thought about it but worried about the high loads causing damage to the small diameter ball-screws on my EMCO F1 Mill. I suppose I could start with an undersize single point cutter and increase it's width in stages finishing off with the broach. Food for thought.

Stop Press.............Another friend, who is not a MEM member, has just offered my the loan of an arbour press and also a small hand shaper. I will collect them over the weekend and see if they are big enough to use. The arbour press, if it is tall enough, could be a better alternative to my drill press. I could also add an angled fixture for the hub.

Thanks again for all your support.

There is hope yet

Mike

It is the journey that matters, not the destination

Offline mikemill

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Re: By Jupiter
« Reply #301 on: May 02, 2019, 03:14:29 PM »
Mike

I think you misunderstand; I am suggesting you mill the slots i.e. the shaft is in the x axis thus no abnormal loads on your machine!

Mike


Offline kvom

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Re: By Jupiter
« Reply #302 on: May 02, 2019, 03:14:49 PM »
Assuming a rotary table is available, I'd use a carbide endmill to rough. each slot.  Either tilt the rotary table or the mill head the angle needed and feed in the X axis.  After the forces on the broach will be much smaller.

The Z axis of most mills are much stouter than the X and Y if you choose to use the head as a press.

Offline Vixen

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Re: By Jupiter
« Reply #303 on: May 02, 2019, 03:33:33 PM »
Mike

I think you misunderstand; I am suggesting you mill the slots i.e. the shaft is in the x axis thus no abnormal loads on your machine!

Mike

Mike, the splines already exist on the shaft. I am trying to make the female splines in the hub. The only access is through the end of the hub

Cheers

Mike
It is the journey that matters, not the destination

Offline Vixen

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Re: By Jupiter
« Reply #304 on: May 02, 2019, 04:00:09 PM »
Assuming a rotary table is available, I'd use a carbide endmill to rough. each slot.  Either tilt the rotary table or the mill head the angle needed and feed in the X axis.  After the forces on the broach will be much smaller.

The Z axis of most mills are much stouter than the X and Y if you choose to use the head as a press.

Hi kvom,

If I understand you correctly, that would mean an end mill of 3/32" (2.39mm ) diameter or smaller,  to rough out the slots each 0.5" ( 12.7mm) long.

Mike
It is the journey that matters, not the destination

Offline Jo

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Re: By Jupiter
« Reply #305 on: May 02, 2019, 06:19:19 PM »
What make was that broach Mike?

We know someone with a slotting head ;)

Its strange how people seem to remember the tools they have seen in your workshop :noidea:

What diameter is the hub Mike? I assume it is bigger than 30mm which is the biggest collet I have for Tgs' Hardinge indexer, so the Theil one would need to be used. It would need a suitable slotting tool made  :thinking:

Jo
« Last Edit: May 02, 2019, 06:22:52 PM by Jo »
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Offline Vixen

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Re: By Jupiter
« Reply #306 on: May 02, 2019, 08:04:36 PM »
Hello Jo

The broach was a 3/32" size A, from Amadeal. It's exactly the same as the Arc Euro ones, except Arc only do metric sizes.

The main cylindrical part of the hub is about 26mm, it mushrooms out towards the rear, where the rear drive flange is welded; so either the Hardige or Teil indexer should be possible.

I don't know anything about your slotting head, what it looks like or even how it works. I guess seeing it in the flesh would save hours of forum time. Perhaps we can get our heads together and discuss the job. I would be very grateful if you could help.

Cheers

Mike
« Last Edit: May 02, 2019, 08:19:01 PM by Vixen »
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Offline Jo

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Re: By Jupiter
« Reply #307 on: May 03, 2019, 04:57:10 PM »
Looks like Mike has two possible ways of doing his splines and they don't involve the excitement of setting up and trying to use my slotting head  :paranoia:

Jo
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Offline kvom

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Re: By Jupiter
« Reply #308 on: May 03, 2019, 07:31:21 PM »
When I bought my Bridgeport it came with a slotting head on the back of the ram.  Definitely seemed an exciting tool to use, so I sold it asap.

Offline Vixen

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Re: By Jupiter
« Reply #309 on: May 03, 2019, 07:44:07 PM »
Looks like Mike has two possible ways of doing his splines and they don't involve the excitement of setting up and trying to use my slotting head  :paranoia:

Jo

Thanks Jo

It was good to be able to discuss the problem with you and Eric and identify alternative ways of achieving the same result. That slotting head for Jo's machine was huge, the size of a small shed. It would have taken ages to install and set up. It looked to be an evil contraption, perhaps an invention of the Devil himself.

Thanks again

Mike
« Last Edit: May 03, 2019, 09:33:30 PM by Vixen »
It is the journey that matters, not the destination

Offline Vixen

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Re: By Jupiter
« Reply #310 on: May 18, 2019, 01:36:56 PM »
After the first disastrous attempt to cut the tapered splines in the propellor hub, I took some time out to discus the problem on the forum and to visit my friends Jo and Eric. My original plan was to machine the hub out of EN3 mild steel and weld on the large diameter rear flange plate. As I found to my cost, EN3 is not a very nice material to machine; it would have been better to use free machining EN1Apb. EN1Apb is alloyed with lead to improve machinability and is a joy to machine. Unfortunately the lead content prevents welding. Eric came to my rescue by providing a length 4.5 inch EN1A free machining steel bar (but without the added lead) so that the complete hub could be machined as one piece.

Another friend kindly provided the loan of a rather substantial arbour press and a large hand shaper. I now had the material and the means to produce the propeller hub by two different methods.One was a better way of applying controlled pressure to the keyway broach, the other would allow the keyway splines to be individually planed on the shaper.

I decided to make some small test pieces from some smaller diameter EN1A before tackling the 4.5 inch bar. The test piece would show whether the keyway broach method could be made to work and would also help with achieving the correct fit of the male and female splines.

A 1.8 degree angle plate ensured the force applied keyway broach was always vertical. The three jaw chuck provided a stable platform to hold the propeller hub. The index plate attached to the propeller hub accurately indexed the tapered broach guide inside the hub taper. The first tapered spline hub showed that this method could work.

The first test piece also showed that the the female splines need to be slightly larger (10 thou) in diameter to fit the tapered propeller shaft correctly.









I now felt confident enough to have a go at the real thing. The 4.5 inch diameter bar was turned to the rough outline of the propeller hub to make it lighter and easier to handle. The EN1A proved to be a nice material to turn. A continuous stream of short, blue chips,  flowed from the insert tip lathe tool thanks to the choice of EN1A







Here are the test piece and propeller hub showing the tapered female splines. Together with the special shortened keyway broach and indexing plate. The replacement broach had to be shortened to 8 teeth to avoid damaging the cone seating at the front of the hub. The 8 teeth cut a total depth of 14 thou. So I used several shims in 10 thou increments to achieve the desired depth of spline.







As you can see, the finished female tapered splines are beautifully even and perfectly formed. The fit of the female splines onto the propellor shaft is also 'spot on' with the correct amount of spline engagement. All that remains to do now is to finish machining the outside of the propellor hub. That can wait until another day



My thanks go to all the MEM members who contributed and especially to Jo and Eric who provided wisdom and encouragement. My thanks also to Stephen who loaned the big Arbour Press and the shaper. Sadly I never got to use the shaper, it looks to be a very useful and fun piece of kit. Perhaps another day.



Jobs a good 'un

Stay tuned.

Mike
« Last Edit: May 19, 2019, 12:17:25 PM by Vixen »
It is the journey that matters, not the destination

Offline Jo

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Re: By Jupiter
« Reply #311 on: May 18, 2019, 03:04:59 PM »
Pleased that worked Mike  :ThumbsUp:

You will have to bring the indexer and test piece along to the Guildford show to show people how you cut the splines  :)

Jo
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Offline Vixen

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Re: By Jupiter
« Reply #312 on: May 18, 2019, 03:29:28 PM »
Hello Jo

That's a good idea.  :ThumbsUp: :ThumbsUp:

I have requested six tables and chairs and also the engine running cage for the Guildford open day 6/7 July. So I hope you and Jason and anyone else who is available,will turn up for one or both days, with a collection of engines to display.

Cheers

Mike
It is the journey that matters, not the destination

Offline Roger B

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Re: By Jupiter
« Reply #313 on: May 18, 2019, 03:36:03 PM »
Excellent job  :praise2:  :praise2: team work is always good  :)  :wine1:
Best regards

Roger

Offline Vixen

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Re: By Jupiter
« Reply #314 on: May 18, 2019, 03:42:42 PM »
Roger,

Yes, Nothing works better than some team work and some controlled violence

Mike :wine1: :wine1:
It is the journey that matters, not the destination