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large curved profile bit

8.7K views 42 replies 20 participants last post by  bobditts  
#1 ·
Having a very tough time finding a bit to make the curve as shown in the picture below. Keep in mind that the full curve in the example picture is about 6". So im looking for a bit with a 3" long shallow curved cutting surface. Can anyone locate such a bit for me? Or possibly there is a better way of doing this without 18 years of sanding? Thanks!

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#2 ·
Hello and welcome to the forum.Bob
 
#3 ·
that's done w/ a reverse profile drawer cutter on shaper....
maybe a finger or thumbnail bit might work for you...
ready made molding comes in that profile...
 
#5 ·
rough hand plane or spokeshave it and sand to finish profile..
 
#6 ·
Hi Bob,,,,just checking. Are you talking about the curve on the box end or the profile on the lid?
 
#7 ·
sorry for the confusion. The curve on the box. I have the MLCS furniture maker bit (item #8592) but it is not nearly large enough and leaves a large flat spot in the profile of the box.
 
#35 ·
I just saw this thread, and followed up on Doug's suggestion. I found this on the Magnate web site:

7586: Cutting Diameter:3"; Shank Length:2"; Shank Diameter:1/2"; Radius:3-3/16"; Profile Height:3/8";
Our Price: $71.74
 

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#11 ·
You could build a curved router jig similar to a jig to plane a board flat only with the curve for which you are looking. That way you would be starting with the same curve for all sides. After that sanding would be required to get the proper finish.

Buck
 
#12 ·
This can be done with a router.
You would build a jig that moves the wood in an arc across the end of a straight bit.

When I made my stave drum shell, I built a jig that rotated the entire shell. The jig for this profile would be similar but only needs to move wood in a 6" arc.

Like the swinging pendulum movement that a grandfather clock has.
 
#13 ·
A while back I did a few boxes with curved sides, (not as acute as those you're looking at, but the same process). Hand planed and block sanded to final form. If reasonably proficient with a hand plane, not as bad a task as you may think...sanding down to proper final form took a little time.

http://www.routerforums.com/twoskies57-gallery/35209-latest-batch-boxes.html

The type of wood you choose to go with will dramatically impact the whole process.


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#14 ·
Make a jig that mounts the box on a pendulum arm at each end. The length of each arm will determine the radius. Then swing the box back and forth over a straight bit on a router table. You'll still need to do some scraping, planing, and/or sanding but not as much.
 
#18 ·
if you hog w/ the table saw you should be able to more than halve the time...
 
#19 ·
Bob I can see that you want to make more than one of these so a router can work, your profile is large so I would get a cutter made for use in a router table, a half cutter, a cutter that does this in one pass would be every large and thin in the middle with a lot of top weight, to hold it together then the middle would have to be very strong and I don't see how that could be made in an affordable way but a half cutter would work, big at the bottom and thin at the top so you would do the cut in a few passes as there is far too much wood to take off in one pass, I would set up to take it off in several passes with the last one the thinnest, the only reason to get a cutter made is that you want to make a hundred of them, making a few, then I would first make the box and then plane it off with the box in a vise, use a profile guide to get them the same. N
 
#20 ·
Hi all, thanks for all the replies. Didnt realize all the activity this thread got. The subscription email feature couldnt keep up I guess. To update everyone, I have a request in to a couple companies to see about getting a custom router bit made. Hoping they come back with some good news.

I do like the idea of creating a jig to use if the custom bit route doesnt work. My biggest obstacle with this whole project is my lack of certain tools (lathe, band saw) and my lack of ability with a hand plane. I am attempting to create several of these projects with uniformity which is why I am seeking the router bit direction. Ill keep everyone posted and again, thanks for all the replies with great information.
 
#21 · (Edited)
To update everyone, I have a request in to a couple companies to see about getting a custom router bit made. Hoping they come back with some good news.
TBH Bob, a 3in router cutter is going to be weak, it will undoubtedly flex when making heavy cuts and probably be a bit of a danger to life and limb - a 1-1/2in cutter run from both sides would make a lot more sense to my mind. (I use 4in long deep pocket mortise bits on a plunge regularly and they can flex if you aren't careful). Even with a router cutter it is still going to be a much safer operation to hog away the waste with something, anything (from a spokeshave to a Surform to a wood file to a power planer....) before you start to work with the router cutter. It's always the heavy cuts where there's the greatest danger of climb cuts and kickback

Regards

Phil
 
#22 ·
Hi Phil. The bit I am currently using has a 1-1/4" cutting surface. Since the lumber (mahogany) is 6" wide, there is a 3-1/2" flat spot in the middle of the piece so I dont get that full curved surface look. I will wait a few days to see what the custom bit companies respond with. If it ends up to be a safety issue, Ill probably just make a jig. I had planned on making several light passes if a 3" bit is doable. Im all about safety with a router (they scare me more than any other tool I own. Definitely use any piece of safety gear when I can. Fingerboards, fence shield, face shield, eye protection, hearing protection, small parts shield, etc...
 
#23 ·
Bob
I can't tell exactly how much is coming off but if you have access to a planer you may be able to get cutter knives ground to that profile. This would only pay if you want to make a bunch but would certainly make the whole process go a lot faster.
Dennis
 
#25 ·
Stick486,

if I had $2400 I would buy this in a heartbeat. Ive been researching all of the info everyone has been suggesting include shaper knives. I have been unable to locate a knife the would do what I am seeking to do. So far, the jig would be the most practical way for my end result with my budget and skillset. I am still waiting to hear back from the custom router bit companies and will post up what they say. Keep the replies coming. I appreciate all of the responses. This forum is awesome!
 
#27 ·
here is the response I got from carbideprocessors.com

Good Day – Thank you for taking the time to contact us.
$345.00 each
Lead time 2-3 weeks
Please let me know if you have any further questions I am happy to help.

Router Bit Specifications
Router Type:
Table Router
Shank Diameter:
1/2
Cutting Diameter:
1 1/4"
Cutting Length:
3"
Hand Rotation:
Right Hand
Number of Flutes:
2
Will Bit be used for End Plunging?:
No
Is Ball Bearing required?:
Yes
Additional Information:
MLCS #8592 is exactly what I need, just much larger.
Router Bit Application
Power Feeding:
No
Material Thickness:
1"
Type of material being routed:
hard woods
Will workpiece cope to another piece?:
No
Please include a sketch or drawing if available:
Quantity:
1
 
#42 · (Edited)
These are the facts regarding commercial production, you really have to be making a lot of something to justify the setting up costs, you have to test your market and then decide if the product will sell and how much money you will put into making it, for what it's worth I like your box design, sadly many persons will not pay what an item is worth and they just want the cheap thing, me, I am not disheartened by that, I am convinced that there are still many persons who will pay more for an item that is made very well, you have to look for these customers and I think that if you do any item 'nicely' then they will sell, your boxes will sell. Have a look at this thread, "New release - SUV" I am sure that if these SUV's were made in large numbers they would sell, so the cost in setting up to make them should pay off. N
 
#28 · (Edited)
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Hi Bob

$345 for a router cutter is fairly heavy. Maybe it's time to think laterally. There are a number of copy router jigs out there, such as this one which are designed to copy 3D objects. That one's $1000, but a simpler version can be built a lot cheaper. With the help of bandsaw or a jigsaw it should be possible to produce a full size template of the cross section of the sides. The cheap router copier jig could be made up with a long bar stylus in place of the point stylus to allow a long length to be copied from a relatively narrow template. Using a relatively low cost ball nose cutter the shaped sides could be routed out to the point where relatively little sanding would deliver the desired result. There are obviously a few issues to iron out to parallelism of the guide bar, but I also have an alternative which I'll post later after I've done a few sketches

Regards

Phil
 
#29 ·
Hi Phil, I completely agree. Definitely not willing to fork out $345 for a single bit. $150 would be my max. The jig is a realistic short term solution that I will most likely pursue.
 
#30 ·
What you could look at is one of these: 72025250 CRAFTSMAN CRAFTSMAN ROUTER CRAFTER Manual | SearsPartsDirect.

Sears made them years ago and you can find them on used tool sites for +/- 50$. I have one that I bought new a long time ago (it scares me to think how long) and have used it to great advantage for some special pieces that would have been awkward on the lathe. I made a jewelry box that was about 5" high from a 6" cylinder. I had to cut off the corners on the bandsaw to get it to fit and then rounded and fluted it (this was before I obtained my lathe). I belive that there is a company that makes a similar devise still and then there is the machines from Phantom Tools, but if 2400$ is somewhat steep...

Otto