MadModder

The Shop => Tools => Topic started by: boxcarmj on September 30, 2010, 12:07:07 AM

Title: Building a Quick Change Gear Bow, need help.
Post by: boxcarmj on September 30, 2010, 12:07:07 AM

Is there a relationship between the spindle gear (40T) and the leadsrcrew (12TPI)? Is there a formula I need to work out? Thank-you Mike.

Title: Re: Building a Quick Change Gear Bow, need help.
Post by: John Stevenson on September 30, 2010, 04:11:48 AM

Yes that ratio is what makes the threads.

You have a 12 tpi leadscrew and 40 T spindle gear, if you fit a 40T to the leadscrew it will cut 12 tpi as it's a 1:1 ratio
Fit an 80T and it now cuts 24 tpi as it's slowed down by a 2:1 ratio

In a straight drive train, i.e. just one row of gears any idlers in the middle run don't count as they cancel out.

John S.

Title: Re: Building a Quick Change Gear Bow, need help.
Post by: boxcarmj on September 30, 2010, 09:46:05 AM

Thank-you John.