Alternatively, summon "Geargiano Mk-III" and use its effect to summon "Geargiano". You will be able to perform a Rank 3 Xyz Summon using up to three monsters, and/or you can use "Gearigano's" effect to revive another machine type monster in attack mode.
Use this card to summon "Geargiaccelerator" or "Geargiagear Gigant XG" from your graveyard for defense. If your opponent destroys this card first you can bring "Geargiano MK-II" back to your hand the moment the other card gets removed from the field. So you can repeat this combo over and over again..Of course you can add "Geargiano Mk-III" to this combo as well. If you allready have a second copy of this card in your graveyard, this combo cannot fail anymore.