Finger-joint router bit?

[Essex Barn Workshop]

Advice please.
I have a router table (Trend) and have been asked by another tenant at the place my workshop is to use his Rockler finger-joint jig (this one)
https://www.rockler.com/router-table-box-joint-jigto make some small boxes for him. He gave me his home made router table, with installed bit to use.
The supplied bit is an edge trimmer, complete with bearing on top, and the supplied table doesn't have mitre slots for the jig so I will be using my table and bits.
The width setting blocks that come with the jig are imperial, and all of my bits are metric.
So I need to buy a 1/4" router bit to make finger joints, but I don't see any future use for it so it must be cheap. It'll only be going through thin, soft wood so needn't be the highest quality.
I should add I did make my own setting block from a scrap of hardwood to fit the jig and be the same width as my 6mm bits, but I don't think it will stand the test of continued use as well as the supplied metal blocks.
What do you recommend please?

 

[Doug B]

Surely you just need a straight router cutter the diameter being the width of the fingers you want to cut, it certainly seems that way from Rocklers instructions http://go.rockler.com/tech/rockler-router-table-box-joint-jig-instructions.pdf
I made my own jig years ago & just used a straight 1/4“ bit they can be picked up for under a tenner.
https://www.wealdentool.com/acatalog/Online_Catalogue_1_4__Shank_237.html

 

[Essex Barn Workshop]

Surely you just need a straight router cutter the diameter being the width of the fingers you want to cut, it certainly seems that way from Rocklers instructions http://go.rockler.com/tech/rockler-router-table-box-joint-jig-instructions.pdf
I made my own jig years ago & just used a straight 1/4“ bit they can be picked up for under a tenner.
https://www.wealdentool.com/acatalog/Online_Catalogue_1_4__Shank_237.html

Thank you, the instructions also say for best results use an up-cut spiral bit, and the collet is 1/2" if that helps

 

[Doug B]

Spiral bits will give a cleaner cut but tend to be expensive, if you’re using a backing block (item 10) on the jig you you shouldn’t get any breakout with a standard double flute bit.

 

[AFFF]

Agree, spiral upcut bit would be my recommendation. Anything else will end up with tearout. It wouldn't be wasted anyway as you could then use it for superior dado and rabbet cutting