Trepanning a deep hole in en24t

This topic has 12 replies, 7 voices, and was last updated 16 March 2017 at 10:08 by Chris Evans 6.

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15 March 2017 at 18:04 #288969
Windy
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@windy30762
I would like to trepan a hole inner Ø 65mm outer Ø 76 110mm deep in en24t.

When 110mm reached it would be parted off a Ø160mm billet x 160mm long

That would leave me a pipe to make my cylinder for my latest project and rest of the billet for a crankshaft.

Have found the en24t ideal for my flash steam hydro cylinder better than a cast iron liner (130+ mph).

It seems such a waste just machining the billet to crankshaft size.

I wonder if my Warco 600 would cope with a trepanning tool of the quoted size.

It would be a home made trepanning tool with either Brazed Carbide or HSS tips.

Any suggestions on a feasible design I have used a 50mmØ hole saw on stainless for a 25mm depth but this project requires a change of design.

The width of the cutter tips can be a lot narrower as dimensions not critical for the roughed out blanks.

Looking at commercial trepanning in the link seems a great deal of power required.

**LINK**

One half of crank roughed out other half to do yet then to finish to size.

Happy days after all those weeks in hospital also got hands oily helping my friend with his TR6 gearbox strip down.

At moment with my latest hair do I look more like Homer Jay Simpson as was told today the following picture was taken a few years ago.

Edited By Windy on 15/03/2017 18:05:43

Edited By Windy on 15/03/2017 18:17:13

Edited By Windy on 15/03/2017 18:19:13

Edited By Windy on 15/03/2017 18:36:12
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15 March 2017 at 18:04 #32925
Windy
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@windy30762
15 March 2017 at 18:22 #288973
HOWARDT
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@howardt
One big problem you will have is getting the swarf out. With carefully cutter design you can use high pressure coolant and get the swarf back out through the cutter. This would make rather a mess on an open machine. Power required would depend on how many cutting edges you can get in.
15 March 2017 at 18:32 #288979
John Stevenson 1
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@johnstevenson1
By the time you have made the tool, broke it and remade it you could have just bored it out. It's not like it's gold, you are not even saving pence on material given the time needed and mistakes made.
15 March 2017 at 18:39 #288980
Windy
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@windy30762
Posted by John Stevenson on 15/03/2017 18:32:11:

By the time you have made the tool, broke it and remade it you could have just bored it out. It's not like it's gold, you are not even saving pence on material given the time needed and mistakes made.

You are probably correct so will give it a rethink.
15 March 2017 at 20:45 #289017
HOWARDT
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@howardt
Why not drill a ring of holes as close together as possible and saw to join up, much easier for the cost of a couple of long drills.
15 March 2017 at 21:25 #289028
Ian P
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@ianp
Posted by HOWARDT on 15/03/2017 20:45:44:

Why not drill a ring of holes as close together as possible and saw to join up, much easier for the cost of a couple of long drills.

The mind boggles!
16 March 2017 at 00:50 #289047
John Ockleshaw 1
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@johnockleshaw1
Hello Windy,

Can you get access to a sink type spark eroder ?. Use a piece of copper tube for the electrode.

Regards, John
16 March 2017 at 00:59 #289048
John Stevenson 1
Participant
@johnstevenson1
A spark eroder will take a minimum of 5 hours to drop down 110mm. At a running rate of say £70 per hour that will cost you £350 to save a £10 piece of EN24.

Priceless – literally
16 March 2017 at 06:41 #289051
John Ockleshaw 1
Participant
@johnockleshaw1
To John Stevenson,

At my place the spark erosion would cost a few KWHr's of electricity. Almost priceless.

John
16 March 2017 at 08:10 #289054
Kettrinboy
Participant
@kettrinboy
I think the stress on both you and the lathe attempting something like this would take years off your life expectancy, as previously said the swarf off 24t is not that easy to break into chips on this type of operation and would wrap itself around in the groove and cause a jam up , better spend a bit more money on materials and make the parts the easy way.

regards Geoff

Edited By Kettrinboy on 16/03/2017 08:11:24
16 March 2017 at 09:49 #289080
Windy
Participant
@windy30762
Afraid it's the Yorkshire man in me i.e. a Scotsman with the generosity squeezed out trying to save money on materials.

So thanks for the suggestions but Johns suggestions to buy more material is the correct way to go.

Wish I could get my en24t at the price he said.

A trade price that my engineering business friend got me with no charge for vat 160mm Ø x 160mm long was over £50.

As an acquaintance from my past he used to watch me doing my thing at sprints and record attempts when he was younger he has even offered to pay for materials like when he got me two billets of 2014 for the crankcases.

I see his speed creations a lot machined on his CNC machines and just look in wonderment we both talk the same language so it's a none stop natter when we meet.

He his a gentleman to the speed scene and has helped many speed enthusiasts to fulfil their dreams.

Here are some of his projects he has done a lot of machining for.

**LINK**

His friends Gem turbine undergoing tests for a land speed motor bike project
16 March 2017 at 10:08 #289086
Chris Evans 6
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@chrisevans6
I buy offcuts from a local steel stockholder, depending on who serves me when I have found a suitable piece (which can be a few visits) the prices vary. On occasion I get lucky and someone will look at the piece and ask for say £10/15. Others will put it on the scales or calculate the weight and then give a cost. Last time I was given a cost was £30 on an invoice or £15 cash. Cash is King ! Having got to know the people at the stockholders does get favours where they will set up a saw and cut for me. This saves me hours over using my "Donkey" saw at home.
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