> Hrappur hleypir fram fyrir og dúði spjótsprikuna er hann
> hafði í hendi og lagði fram fyrir sig og kvað þá vera allt
> mál að reyna sig.

> Hrappr gallops forward before and shook the spear-head
> which he had in hand and stabbed forward before himself
> and then said is all a case to experience oneself.

> Hrapp ran forward ahead and shook the spear point which he
> had in hand and thrust forward ahead of him and said then
> to be high time to prove himself.

> Hrappr gallops-swiftly in-front and shook the spear-prick
> (head, tip) which he had in (his) hand and thrusts (it)
> forward before himself and declared then (it) already (or
> altogether, allr, Z5, or allt, Z3) high-time (mál, Z2) to
> be proving oneself.

Like Grace, I think that the entire phrase <allt mál> can
reasonably be translated 'high time'.

> Verða þeir Helgi þá eigi fyrr varir við en þeir Þorgils
> taka á þeim selið.

> They don't become aware of Helgi before that they,
> Thorgils (and the others) themselves touch the hut. (?)

> They, Helgi (and co) did not then become aware and they,
> Thorgils (and co.) reach? the shieling.

> They, Helgi (and co) became (were) not then on-their-guard
> against (it) before they, Þorgils (and his co) reach
> the-shieling with them (?).

<Þeir taka á þeim selit> is a bit of a puzzle. This is not
<taka á e-u> 'to touch something': <selit> is accusative,
not dative, so it can’t fill the <e-u> slot, and if dative
<þeim> is used to fill it, there’s no place for <selit>.
Kålund, the editor of my other edition, and MM&HP agree that
it means 'they surround the shieling'; one possible more or
less literal reading is 'they take to themselves the
shieling', which I guess isn’t an unreasonable way to
express the notion of surrounding something.

> Helgi svarar: "Fyrir það mun þér ganga sem sá sé nokkuð
> skæður er hér býr inni að hann muni bíta kunna nær
> greninu."

> Helgi answers: "Before you will go as they are somewhat
> dangerous who live inside here that he would know (how) to
> harm nearer the lair."

> Helgi answers, “Because (of that) it will go for you as
> that were something noxious here inside (the) farmhouse
> that he will know to bite near the lair.”

> Helgo answers: “That will go forward for (That will
> present itself to) you that that-one (ie he) be somewhat
> noxious who here resides inside (such) that he will
> be-able-to bite (strike) near the (ie his own) fox-hole.”

The finite verb must be the first or second element of the
sentence. In <Fyrir þat mun þér ganga> the finite verb is
<mun>, so <fyrir þat> must be a single element, and the
subject of <mun> must be unexpressed. It must be something
like ‘[It] will go for that to you [i.e., you will discover]
that he who lives inside here is somewhat dangerous [in]
that he will know [how] to bite near the [= his] lair’.
<Kunna + infinitive> meaning 'to be able to X' seems to use
the full infinitive with <at>, so I chose to translate
<kunna> as 'know'.

> Þorsteinn svarti stóð fyrir selsdurunum og Sveinn son
> Dala-Álfs en þeir aðrir förunautar rifu af ræfrið af
> selinu og höfðu þeir þar skipt liði til.

> Thorstein Black and Svein, Dala-Alf's son, stood before
> the hut's doors and the other companions tore off the roof
> from the hut and they had there divided (their) troops.

> Thorstein the black stood before the shieling doors and
> Svein, son of Dala Alf and those other comrades tore off
> the roof from the shieling and they had there divided (the
> company) to (the work).

> Þorsteinn (the) black stood before the-shieling-door and
> Sveinn son-of-Dala-Álfr (Álfr of the Dales) but (and)
> they, (the) other travelling-companions tore off the-roof
> from the-shieling and they had there divided the troop
> thereto (ie for that task).

I think that <þeir> in <þeir aðrir förunautar> is the
demonstrative pronoun, not the personal pronoun: 'the other
travelling companions, those other travelling companions'.