No. You can only take deductions for giving money to recognized charities. You can never deduct the value of items or cash given to family members, unless they are being paid to work for your business (i.e. not a personal thing).

If you give more than the annual gift limit to a single person in one year (currently, $14,000), you have to file a gift tax return.

https://www.irs.gov/businesses/small-businesses-self-employed/frequently-asked-questions-on-gift-tax...

If the grandchildren are still young, you might want to consider a 529 plan to help them save for college. Your state may allow a benefit to you, and the benefit to your grandchildren may be great.