Anyone know how to make a convex profile?

[Derek Larson]

I have scoured the router bits on the Internet for a few days and i cannot find a bit that makes a long (about 1.5") shallow convex profile. The bits that I have found are too short about 3/4" convex profile and they also create a flat edge at each side of the profile which i don't want. Should I be looking elsewhere other than at router bits.

It might help to explain what I want to do, basically i want to cut a convex profile into rail and stiles, and then on each side of the convex profile there would be a simple beaded edge or something not sure yet.

The closest bit I found was actually provided to me by someone else in this forum for another project I have, it is close and will give you an idea as to what i am looking for I just don't want the decorative edge that comes with it.
http://www.sommerfeldtools.com/item....1010&d=102&b=1

Someone else mentioned a crown molding bit but again those all come with more decorative edging than I want. unless you can remove part of the crown molding bit?

Just curios if there was a bit or another method for doing this

Thank you

[Peter Quinn]

Does this bit in two passes help?

http://www.infinitytools.com/products.asp?dept=1078

Could get a custom bit made from Whiteside or amana.

[john bateman]

Youcan sorta do that with a thumbnail bit. It would require two passes with your stock face down. Do one edge, then the other. With the bit upside down in a router table, you'd raise it just enough so that the flat bead portion would not be formed.
http://mlcswoodworking.com/shopsite_.../bt_table.html

[Derek Larson]

Thank you peter that infinity bit just might work. The other bits that were similar to that all had a flat edge that I could not avoid. I will definitely check that one out.

Now has anyone ever had a custom bit made? is costly or hard to get it just the way you want?

Thank you

[Peter Quinn]

worked in a cabinet shop that used mostly shapers but had the occasional router bit custom made. Don't know the cost, but if you can draw it they can make it assuming the bit is safe to spin. Call whiteside, amana, cmt or I think infinity makes um too. wont cost anything to ask.

[Vince Shriver]

I would imagine that having a custom bit ground could get pricey. Sort of depends how much you would use it as to how expensive it is in terms of "cost per job". This is a small company in Calif and they are excellent; I'm sure they could make your bit if you decide to go that way. Paso Robles Carbide (805) 238-6144

[Jim Becker]

If I'm understanding the profile you really want, it sounds like it may be best done using a moulder rather than a router. Is this something similar to what you are looking for?

ScreenHunter_01 Feb. 07 11.50.gif

[Peter Quinn]

Deric...you might try sourcing the molding you need from a custom milwork house regionally or on the web. Seems like possibly a fairly standard profile. What species? Might be able to get an acceptible stock profile from some molding companies...or maybe now is the time to go for that Williams and Hussey!

[Derek Larson]

Jim that is about what I am looking for, not exactly sure what I would do after the convex profile, but yes something like that. Now you mention a moulder and I do not currently have the funds to purchase one, but that doesnt mean I can't start researching them. So I guess my question is does anyone know a good website or book that would be a good starting point that would explain the the basics of a moulder because I know nothing about them, other than that some look like planers.

Thank you

[Peter Quinn]

Derek, google Williams and Hussey for starters. Good web site. Small molder for the well financed hobbist or small pro shop. Can do curved moldings as well as straight, lots of stock profiles and most custom tool grinders make knives for them. Its the one Tom Silva uses on THIS OLD HOUSE. Shop fox makes a cheaper knock of I hear works great. Jet makes one too, no experience with it.

The idea is like a planer with edge guides and profiled knives which cut from above. You can do a lot of molding on a good shaper, but it can get scary.
For laughs google Weinig Group, check out a big 7 Head industrial molder ($75K-$250K). Worked in a shop with four of them running at once...those are for factories making moldings and flooring at the clip of 150,000LF/wk/machine.

If you google custom moldings there's lots of regional firms that stock many profiles in different species. Shop I worked in charged $150-$350 setup fee regardless of order size, $120/inch for custom ground knives. Mostly sold to builders/architects on $1mil÷ homes.

Some local craftsman placed orders and saved by waiting till a big order came in for that profile , the boss would just push their order through without setup fee, charge it to the big order. which worked if it was a popular profile that was ordered regularly. They had about 3000 different knives, some profiles more popular than others. They stocked popular profiles on a few basic species which was the cheepest way to go if it meet the need. Lots of these operations around the country, many will ship. Any one order is cheaper than a molder.

You can always do it by hand with a scratch stock if your total quantity is limited.!

[Peter Quinn]

running it through my head while my baby is sleeping, you can pull it off with the Infinity bit and a quirk bead bit on the router. Probably need 6-8 passes (2-3 light passes, increasing depth of cut each time for the convex, 1 pass for each bead). gotta have a router table setup that gives you proper height above the table, maybe the Extreme extension? otherwise you could glue the two beads to the convex center. Probably safer using 8/4 stock or a lamination, molding the edge, give yourself at least 6" width and extra length to keep your fingers clear of the cutter, use featherboards. Have to run and rip, safer to rip half the depth, flip and rip the rest. Safer still to rip on a band saw if you have one, then clean up back in 1-2 passes on jointer or rip over thickness and use the planer. I'm sure its doable, just take a few careful setups and a little sanding/scraping.