need help with rail and stile cabinet doors with adjustable router bit

[Jean Galluccio]

I'm new to this website and thought it would be a good place to get some advice. I am trying to make rail and stile cabinet doors with 1/4" plywood panel and maple frame. I purchased Freud adjustable rail and stile router bits, so I could adjust for the plywood panel, which is slightly less than 1/4". I made a practice door before starting, and everything worked fine. The rails and stiles fit snuggly, but not tight, after I adjusted the bits. For this door, however, I used poplar, since I had some on hand, and didn't think this would make a difference. Today I worked on making 2 doors, using maple now, however, but I was having problems with the rails and stiles being loose when put together. I hadn't adjusted the rail and stile router bits since making the practice door from the poplar, though. I then tried adjusting the bits using the shim/spacer, but adding one shim (the thinnest one) to the bit which cut the tongue to make it thicker, and did a practice peice to check the fit. Now the tongue was too thick for the groove. So I have a few questions:
1. Would router bits work any different on maple than on poplar in terms of the loose fitting rails and stiles with maple?
2. The thinnest shim/spacer is not thin enough to adjust the router bit so the rails and stiles fit comfortably - snug, but not tight. Can someone recommend how to move forward? I love the router bits, aside from this issue right now.
3. If I were to assemble the doors when the rails and stiles fit loose, would they hold?
Thanks for any input!

[jack duren]

Most of those cutters are fairly acurate but not tight. when you put the stile/rail together they shouldn't wiggle around but should close on the top and bottom gaps. Whats in between should be snug but not too tight....

[Peter Quinn]

Poplar tends to shred a bit on the cross grain milling where maple mills much cleaner, so poplar could easily feel a bit more snug. The difference between a good fit and one that is too loose/tight is only a few .001's of an inch. I'm not sure what size shims your bits came with, but you should be able to make precise adjustments for a just snug fit (leave room for glue!). I have a few amana router bits that are adjustable, and the bits came with shims but not a wide enough variety of the smaller sizes for my liking. I ordered a few bags of precision washer/shims from McMaster Carr, they were sold in bags of 50 and were metric IIR, the same ID and OD as the originals. I got .002", .005", .010" and something close to .025" (again, these are my SAAE translations of metric shims, they were sold in MM). Life time supply, not very expensive, now I have complete control over stacked router bits. I use dial calipers to measure both the tongue and groove on a sample, then adjust one or the other with the shims (using the calipers to measure those too) so the tongue is about .005" less than the groove.

In your case you want to adjust the groove to the plywood panels then the tongue to this groove, I think your on the right track there. I use mostly shaper at home and at work, with shapers its pretty much understood that most sets are adjustable, a good shim kit is invaluable there, and IMO also quite handy for the router table.

[Jim Hager]

Most 1/4" plywood is too thin for a regular style and rail set. I don't do any of mine with a router but shapers. I have a special slot cutter and rub collar for my shaper to get the plywood to fit more snugly in the slot. On all my flat panel doors I use MDF core plywood which is much more the correct size for the 1/4" groove. I have had no issues on 1000's of doors I put out of my shop using the MDF. I use the fiber core plywood on all my custom kitchens for either door panels or end skins for the cabinets. Sorry I don't run the router to make doors and can't really give any up to date advise on adjusting the cutters. However you may think that the tongue should fit more tightly than it has to. My stuff slips together pretty easily with several thousands room for glue. I don't know how many but I'd say easily .005 maybe more. Gotta have room for the glue.

[jack duren]

"Gotta have room for the glue" Not really, you'll crack the rail or couldn't get it in before you wouldn't have enough room for glue.