I have a question about taa and kaaf...

ssalamu 'alaikum wa rahmatullahi wa barakatuh

I have a question about taa and kaaf. Both have the quality of ash shiddah and strong reliance on the makhraj but both also have al hams, the letters of which have a weak reliance on the makhraj.

Looking at the letters of al hams the taa and kaaf seem to be the odd ones out. Are they included due to al hams being the mechanism by which the problem of sound being imprisoned behind the makhraj is resolved for the taa and kaaf?

How is the strong reliance of ash shiddah and the weak reliance of al hams being present in the same letters reconciled?

Jazakallahu khairan

Wassalamu 'alaikum wa rahmatullahi wa barakatuh

Wa alaikum assalaam wa rahmatullahi wa barakatuh,
A very good question, masha' Allah.
You are correct, that the present in the  and  helps them get rid of the pressure built up at the makhraj due to the characteristics of .  The other letters of rid of the pressure by qalqalah,  with the exception of the hamzah which for some of the qira'aat has the pressure released by changing the hamzah. 
The pressure built up in the letters of is especially noticeable when the letter is saakin.  In this case,  the and which are saakin have the shiddah occurs first, and the hams after that.  This is the only case when the sifaat are not applied simultaneously, so this reconciles the two characteristics as they are not applied at the same time.
When the letter is voweled, the pressure build up for the characteristic of   is not  as strong and there is not a problem applying both and at the same time.

Please also see:

Wa iyyakum.
Wa assalaam alaikum wa rahmatullahi wa barakatuh