# New router , old dovetail jig



## kdr152004 (Feb 29, 2016)

Dear router forum, 

I recently picked up an old craftman dovetail jig model # 315.25790 on craigslist, only to realize that it’s design to be used with a ¼’’ shank router (and 7/16’’ guide bushing), thus it’s incompatible with my DW618 Dewalt ½’’ shank router. 
Can anyone offer me any advice for how I can modify the jig to accept my router without breaking the bank? I know I could get a shank adapter and ¼’’ dovetail bit, but that would run me much more than I paid for the jig in the first place, and I’m not even sure if it would work. 
Thanks, 

-kdr152004


----------



## DonkeyHody (Jan 22, 2015)

Didn't your router come with a 1/4 inch collet as well as 1/2 inch? If not, consider the 1/4 collet a long-term investment, not just something you need for your dovetail jig. You'll find lots of the smaller bits are hard to locate in 1/2 inch shank. 

This entire hobby is one big snowball. Everything you bring home somehow leads to another purchase. I see no end in sight. If you wanna dance, you gotta pay the fiddler.


----------



## kdr152004 (Feb 29, 2016)

Oh yeah, I do have the 1/4'' collet!

So for a 7/16'' guide bushing, should I use a 5/16 'large diameter' dove bit (1/4'' shank)? 

Thx, 

-kdr152004


----------



## Nickp (Dec 4, 2012)

Your manual cites needing to use router bit 26319 and 26318 for 1/4" and 1/2" dovetails (does not give dimensions). To be positively sure, you should get dimensions and angles of the Sears bits before trying other mfg's bits.

More directly answering your question...it depends on the side to side clearance between bushing and template.


----------



## kdr152004 (Feb 29, 2016)

I'm planning to cut 1/2'' dovetails, but sadly I cannot find any dimensions on the 26318 bit . It must be smaller than 7/16'' otherwise it will not fit through the guide bushing hole. This is rather confusing


----------



## Nickp (Dec 4, 2012)

You might try contacting Sears or Ryobi (as identified by the 315 in the Sears part #)...


----------



## kdr152004 (Feb 29, 2016)

Yeah, Sears was not helpful at all. I'm hoping someone on the forum has more info.


----------



## Nickp (Dec 4, 2012)

kdr152004 said:


> Yeah, Sears was not helpful at all. I'm hoping someone on the forum has more info.


With the 7/16 bushing in the template, measure the side to side clearance...if it is 3/16, the 5/16 bit should work...total of clearance plus bit size equal 1/2"...as doublecheck also measure template finger...in this case it should be 1/4...bit should be 1/2" tall...


----------



## kdr152004 (Feb 29, 2016)

Dear Nickp, 

I was able to find some info! The manual calls to use a craftman 25531 which is a 1/2'' dovetail bit (1/4'' shank) with a 7/16'' OD guide bushing. This make sense as the distance between the fingers and the finger width are both 7/16'', leading to 1/2'' dovetails with a 1/2 inch bit. 

I was confused , as the cutter (1/2'') is larger than the opening on the guide bushing - but , only the 1/4'' shank has to fit through the bushing to install the bit, correct ??? Thus I would just need a long-enough bit to fit into the router so that the cutting surface clears the guide bushing. 

Thanks again, 

kdr152004


----------



## Nickp (Dec 4, 2012)

Correct...just make sure the collet is adjusted all the way down to get the maximum amount of the shaft inserted. You may be better off with a bearing guided bit rather than bushing...

As the distance between fingers is 7/16, yes a 1/2 bit is necessary with a 7/16 bushing...

Remember to back out the router before lifting...


----------



## kdr152004 (Feb 29, 2016)

I got the setup working with a whiteside dovetail bit (1/4'' shaft, 14 degree, 1/2'' cutting length, 2 3/8'' length) . To get good fitting tails, it seems I need to lower the bit as far as possible, to the point where it's about 1/32'' away from hitting the inner part of the guide bushing...... I'm wondering, would the carbide cut the brass, or vice versa?


----------

