[Suresh Stephen]

Originally Posted by SPIKE ARRESTOR

Can anyone elaborate, what hardening is being referred here?

Spike

Dear Spike,
I had an axle set like Santhosh had in the FFRA set up and I also has an LSD in the rear. After an OTR in Munnar I found that my axles were twisted very badly. When I checked the hardness it was around 20 HRC whereas for a properly heat treated shaft, I will expect an minimum of 35HRC( depending on the material and heat treatment). I have then got a pair of axles manufactured using EN36 steel and got a proper hardening and tempering done which gave I think about 40 HRC. It was a pain to establish the manufacturing process and i have lost at least some four pairs before establishing the right process. especially which quenching, the shafts used to distort. I have introduced straightening after then with the reference of the splines idone a grinding operation which has removed all the distorsion and also improved the sealing on the axle. Now the axles are working fine But the drive flange spline was eaten away. I have now done an argon arc welding on the axles and drive flange.
Santhosh,
You may not require the thrust spacer. What is required is to ensure that the splines in the inside and outside is properly meshed. Ask Raju to locate axle in the correct distance , cut the extra bolt length and clamp it right other wise you may have oil leaks.
Suresh

[svsantosh]

Originally Posted by Suresh Stephen

Santhosh,

You may not require the thrust spacer. What is required is to ensure that the splines in the inside and outside is properly meshed. Ask Raju to locate axle in the correct distance , cut the extra bolt length and clamp it right other wise you may have oil leaks.

Suresh

Thanks Suresh sir... Sivakumar (chennai) was right when he warned me to check something regd custom axles that you had hand crafted... I will also check with Raju on the above quote. I will call you later in the day to learn more. Welcome back...

[SPIKE ARRESTOR]

Originally Posted by Suresh Stephen

Dear Spike,
I had an axle set like Santhosh had in the FFRA set up and I also has an LSD in the rear. After an OTR in Munnar I found that my axles were twisted very badly. When I checked the hardness it was around 20 HRC whereas for a properly heat treated shaft, I will expect an minimum of 35HRC( depending on the material and heat treatment). I have then got a pair of axles manufactured using EN36 steel and got a proper hardening and tempering done which gave I think about 40 HRC. It was a pain to establish the manufacturing process and i have lost at least some four pairs before establishing the right process. especially which quenching, the shafts used to distort. I have introduced straightening after then with the reference of the splines idone a grinding operation which has removed all the distorsion and also improved the sealing on the axle. Now the axles are working fine But the drive flange spline was eaten away. I have now done an argon arc welding on the axles and drive flange.

Hello Sir,

Thank you for your reply, although I know hardening and heat treatment processes for axle and its components, i wanted to know which hardening was being referred to here by Arka and Santosh, and hence the query. I would like to add on:-

1. As you have used EN36 steel what kind of heat treatment was done (single quench/double quench followed by tempering?)to obtain a particular carburised depth.

2. I will tell you the procedure with EN8D optional SAE1541.
Metallurgical process- Hot forging followed by Normalising to core hardness of 197 BHN then shot blasting. Induction hardening and tempering is done to achieve the following:-
a) Surface hardness 54-60 HRc
b) Effective case depth at 40 HRc 4.3 to 5.6mm
c) Total case depth at 20 HRc 7.2 to 8.5mm
Core hardness of 197 BHN is checked at the end of the total case depth and surface hardness is maintained +-1 HRc up to minimum depth of 3mm from surface.

Spike

P.S. BTW what kind of spline does it incorporate?

[svsantosh]

Originally Posted by SPIKE ARRESTOR

....i wanted to know which hardening was being referred to here by Arka and Santosh, and hence the query..

Pratheesh - Dont count my name in the 'referred to here' list. I have no clue what Arka, Suresh and you guys wrote above. I am calling Suresh sir right away!!! This is too much input into my finance brain!!

[Suresh Stephen]

Originally Posted by SPIKE ARRESTOR

Hello Sir,

Thank you for your reply, although I know hardening and heat treatment processes for axle and its components, i wanted to know which hardening was being referred to here by Arka and Santosh, and hence the query. I would like to add on:-

1. As you have used EN36 steel what kind of heat treatment was done (single quench/double quench followed by tempering?)to obtain a particular carburised depth.

2. I will tell you the procedure with EN8D optional SAE1541.
Metallurgical process- Hot forging followed by Normalising to core hardness of 197 BHN then shot blasting. Induction hardening and tempering is done to achieve the following:-
a) Surface hardness 54-60 HRc
b) Effective case depth at 40 HRc 4.3 to 5.6mm
c) Total case depth at 20 HRc 7.2 to 8.5mm
Core hardness of 197 BHN is checked at the end of the total case depth and surface hardness is maintained +-1 HRc up to minimum depth of 3mm from surface.

Spike

P.S. BTW what kind of spline does it incorporate?

Dear Pratheesh,
En 36 is not the best steel for shafts. It is a gear steel. Since I was not sure regarding the the hardness of the internal splines in the LSD, I have not case hardened the splines. En 36 is closely eqivalent to AMS/ SAE 6260 and 16 NCD 13 gear steels. It gives an Ultimate tensile strength of about 1300 Mpa. I had a quick check on the spline stresses before deciding on the material and found En8 ( UTS of EN8 is around 500 MPa)was on the margin ( dont forget, I did not want to case harden the spline ends). I have only through hardened this steel . Typically it will be heated to 800+ deg followed by oil quenching. which gives about 340 to 410 BHN( 36 to 44HRC)
May be En 24 / SAE 4340 was a better and cheaper option since I have opted for through hardening.
The splines were involute side fit. I think it was 1 or 1,25 module 30 deg pressure angle( I forgot). It was generated by shaping using a "fellows" shaper.
If iam case hardening this spline, I will have about 0.2 to 0.3 mm (max)with a maximum hardness of about 60 RC and the depth of case hardenening will be defined at about 55HRC.
Regards,
Suresh

[SPIKE ARRESTOR]

This is reasonable and good enough, now i understood why you selected EN36 steel. Your splines are being eaten up, does that attribute to the material properties inherent to the LSD?

Spike

[Suresh Stephen]

Originally Posted by SPIKE ARRESTOR

This is reasonable and good enough, now i understood why you selected EN36 steel. Your splines are being eaten up, does that attribute to the material properties inherent to the LSD?

Spike

Pratheesh,
I lost the female splines of the outer drive flange which was obviously soft. LSD side is fine.
Suresh

[svsantosh]

Suresh Sir, Are you referring to two different issues here?

1) OE Axle itself loosing its structural integrity and bending.
2) The above led to the outer flange loosing its female splines?

Did (2) lead you to welding the axle to the outer flange?

[Jaggu]

Half of this went over my head! but its good to know that axles can be made (i mean its not impossible, though it sure sounds close to being so). I was always worried about the situation when we run out of first and second hand spares.

[Sutripta]

Originally Posted by Suresh Stephen

The splines were involute side fit. I think it was 1 or 1,25 module 30 deg pressure angle( I forgot). It was generated by shaping using a "fellows" shaper.
Regards,
Suresh

Sir, any thoughts on generating the involute profile on the spiders for one offs (No broaches etc).

Regards
Sutripta

[Suresh Stephen]

Originally Posted by svsantosh

Suresh Sir, Are you referring to two different issues here?

1) OE Axle itself loosing its structural integrity and bending.
2) The above led to the outer flange loosing its female splines?

Did (2) lead you to welding the axle to the outer flange?

Dear Santosh,
1.When I converted to FFRA I have used a "Talbros" make axle which is supposed to be a good make. It is this axle which has twisted
2. I have made new axles with improved hardness and they have killed the female spline of the outer drive flange and hence I have a decided to weld the two together.

Originally Posted by Sutripta

Sir, any thoughts on generating the involute profile on the spiders for one offs (No broaches etc).

Regards
Sutripta

Dear Sutripta,
It is possible to make internal splines in a spider by using a shaper. you need to plan at least two sets to cater for rejection. Small quantities will normally be expensive due to initial toolings/ setting costs
Suresh

[Sutripta]

Originally Posted by Suresh Stephen

Dear Sutripta,
It is possible to make internal splines in a spider by using a shaper. you need to plan at least two sets to cater for rejection. Small quantities will normally be expensive due to initial toolings/ setting costs
Suresh

Thanks for the prompt reply.

The tool will have to project quite a bit from the ram. Will it be rigid enough.
What do you think of machining the inner splines on a VMC with a small dia cutter?

Regards
Sutripta

[Suresh Stephen]

Originally Posted by Sutripta

Thanks for the prompt reply.

The tool will have to project quite a bit from the ram. Will it be rigid enough.
What do you think of machining the inner splines on a VMC with a small dia cutter?

Regards
Sutripta

No I don't think you will have execcessive tool projection. Are you trying to make a form cutter and rely on the indexing accuracy of the machine?. It is a feasile solution provided the machine is good. You can also consider EDM also as option but then you need to generate the correct tooth profile from first principles and make the tool with it
Suresh

[svsantosh]

Originally Posted by Jaggu

Half of this went over my head...

Slightly OT -

My dad is visiting bangy (lucky for me) and when I was busy comprehending this thread, he offered me a 1hour session on his engineering experience. I now totally understand EACH word Suresh and Pratheesh sirs' are talking here...

He worked with a (1 Company all his life) OE Clutch supplier to M&M (&TATA, Maruti, Ash.Ley, Bajaj, Mazda etc) for all his life since grad school TILL Retirement. He patiently explained the process of cold Vs hot forging, types of steel, (medium/high carbon etc), different standards of steel Ex, Exx, SAExxx, etc etc, tempering, quenching (oil, water, salt), HARDNESS Vs FLEX Vs STRENGTH... Man - I lost my sleep, this talk went on till 12 in the night!!

[Sutripta]

Originally Posted by Suresh Stephen

...
Are you trying to make a form cutter and rely on the indexing accuracy of the machine?. It is a feasile solution provided the machine is good. You can also consider EDM also as option but then you need to generate the correct tooth profile from first principles and make the tool with it
Suresh

Hi,
You're right.
For one offs one can even use EDM for cutting out the entire shape. Of course, offends ones sensibilities in using an essentially toolroom process as a manufacturing process.

Regards
Sutripta