The NEW Build Your Own Arcade Controls

Main => Woodworking => Topic started by: DaOld Man on September 02, 2017, 08:31:16 pm

Title: How can I round this sharp edge?
Post by: DaOld Man on September 02, 2017, 08:31:16 pm
I am working on a control panel made of 1/2" MDF.
I cut two pieces at matching angles and glued them together, to form a CP with the front attached.
This resulted in a sharp edge, which I would like to "round off".
Due to the steep angles of the two pieces, I cant really use my router with a round over bit.
Any ideas how I can accomplish this?
See the attached crummy drawing to give you an idea what Im doing.
Title: Re: How can I round this sharp edge?
Post by: PL1 on September 02, 2017, 09:21:58 pm
I am working on a control panel made of 1/2" MDF.
I cut two pieces at matching angles and glued them together, to form a CP with the front attached.
This resulted in a sharp edge, which I would like to "round off".
Due to the steep angles of the two pieces, I cant really use my router with a round over bit.
Any ideas how I can accomplish this?
Look for "Round Over Bowl" bits like this one (https://www.amazon.com/Freud-85-001-2-Inch-Round-Router/dp/B00004T7L0/) (15 degrees) or one of these (http://www.routerbitworld.com/Round-Over-Bowl-Bits-s/271.htm). (some are only 10 degrees)

(https://images-na.ssl-images-amazon.com/images/I/31NWATJ2X3L.jpg)


Scott
Title: Re: How can I round this sharp edge?
Post by: DaOld Man on September 02, 2017, 10:01:39 pm
Due to the steep angles of the two pieces, I cant really use my router with a round over bit.
Title: Re: How can I round this sharp edge?
Post by: PL1 on September 02, 2017, 11:09:51 pm
Due to the steep angles of the two pieces, I cant really use my router with a round over bit.
How about a concave sanding block or pads like this set (https://www.amazon.com/Concave-Sanding-Pads-Set-4/dp/B003A07V4A/) or this set (https://www.amazon.com/Large-Contour-Sanding-Pads-Set/dp/B003A09N8C/)?

(https://images-na.ssl-images-amazon.com/images/I/712HRYIBK0L._SL1500_.jpg)

You could even make one using a piece of cove molding (http://www.homedepot.com/catalog/productImages/1000/d4/d4b9e0c9-0144-49c4-a146-9fb2e1f13ec0_1000.jpg).

(http://www.homedepot.com/catalog/productImages/1000/d4/d4b9e0c9-0144-49c4-a146-9fb2e1f13ec0_1000.jpg)


Scott
EDIT: Added cove molding image link since the image wasn't showing up.   ???
Title: Re: How can I round this sharp edge?
Post by: DaOld Man on September 02, 2017, 11:40:05 pm
I like that idea. Might just work.
Title: Re: How can I round this sharp edge?
Post by: lilshawn on September 03, 2017, 01:38:39 pm
Due to the steep angles of the two pieces, I cant really use my router with a round over bit.

but that bit has an angled bearing surface to work on angled (not 90 degree) pieces.
Title: Re: How can I round this sharp edge?
Post by: DaOld Man on September 03, 2017, 04:42:03 pm
Hmmm, hadnt noticed that, but 61 bucks brings out the tight wad in me. LOl
Title: Re: How can I round this sharp edge?
Post by: PL1 on September 03, 2017, 05:23:41 pm
Hmmm, hadnt noticed that, but 61 bucks brings out the tight wad in me. LOl
Then cove molding is the way to go.  :lol

Forgot to mention that you'll probably need to trim the molding (red lines) since the angle between the CP and front (yellow lines) is over 90 degrees (blue arc) -- otherwise the corners will hit before you reach the desired curve profile. (white arc)


Scott
Title: Re: How can I round this sharp edge?
Post by: jennifer on September 04, 2017, 12:35:28 pm
Hmmm, hadnt noticed that, but 61 bucks brings out the tight wad in me. LOl
Then cove molding is the way to go.  :lol

Forgot to mention that you'll probably need to trim the molding (red lines) since the angle between the CP and front (yellow lines) is over 90 degrees (blue arc) -- otherwise the corners will hit before you reach the desired curve profile. (white arc)


Scott
   I just never seem to ever learn that, just this morning Jennifer messed up that cut :-\....It seems getting it to fit and then cutting it to size works best for me, That way you get a few tries at it before you run out of wood.
Title: Re: How can I round this sharp edge?
Post by: DaOld Man on September 04, 2017, 11:12:37 pm
I had a wild idea. I used a round over router bit and scraped the edge with the cutting radius of the bit. I held the router bit by hand and dragged it across the corner.
It might work, but I did scratch up the flat area on either side of the corner, hopefully a little sand paper and elbow grease will fix that.
Title: Re: How can I round this sharp edge?
Post by: DaOld Man on September 05, 2017, 06:38:24 pm
Well, the rounded corner looks pretty decent, but the scratches are pretty deep. Tried filling them with wood glue but that aint gonna work.
I have 3 options that i know of:
Try bondo on the scratches (might work).
Scrap it and start all over (lot of work and I will still have the rounded corner problem on the new piece.)
Cover it with laminate. I like this idea, but the laminate I have will not bend that sharp. Tried heating it but it still cracked around the bend.
Anyone have any suggestions on bending laminate? Is there a special type you have to buy?
Title: Re: How can I round this sharp edge?
Post by: DaOld Man on September 05, 2017, 06:57:38 pm
One other option could be thin sheet metal?
Im not used to working with metal, but Im not dead yet so it's not too late to try I guess LOL
Title: Re: How can I round this sharp edge?
Post by: morton on September 05, 2017, 07:22:15 pm
That bit that PL1 posted is wicked cool.

Same situation as you... I just used sandpaper on mine to take the edge down. I have almost the same angle. You'd need an eagle eye to tell that it's done by hand. Just go slow and patient and don't rush.
Title: Re: How can I round this sharp edge?
Post by: PL1 on September 06, 2017, 01:03:23 pm
Here's another approach using the "Angle Cut Tool for Table Saw Sled" shown in the video here (https://www.youtube.com/watch?v=3SuGxQ2XBlg).

Angle Cut Tool for Table Saw Sled (http://www.youtube.com/watch?v=3SuGxQ2XBlg#)

1. Start with the control panel top piece

2. Use a properly adjusted router table with fence and roundover bit to round the edge.

3. Use the adjustable angle table saw sled (yellow) shown in the video to cut off the red.

Position the piece horizontally so the edge of the cut is exactly the radius of the curve from the edge.

4. Flip the piece over, change the sled angle so the cut is horizontal, adjust the fence position/blade depth to cut a groove.

5. Without adjusting the fence, cut a groove in the vertical board (blue) -- same distance from blade to fence for both groove cuts.

6. Cut a piece of wood (green) exactly the width of the groove and glue everything together.   ;D


Scott
Title: Re: How can I round this sharp edge?
Post by: bperkins01 on September 09, 2017, 10:44:47 am
Bondo will fill the scratches..
If you make a long sanding block - you can sand east-west to smooth the curve.  Its called longboarding in boat building.
If you are really finicky you can cut a profile template and check the shape at intervals along the edge.

A vinyl wrap could cover it all too.
 
Title: Re: How can I round this sharp edge?
Post by: jennifer on September 14, 2017, 12:30:33 am
   Its so fun your back at the workbench (not dead yet, Whatever ::)) Jennifer has to make an observation however, 1/2" seems a bit thin (IMO) 3/4" with holes recessed from the back would give more substance to it. #2, capping it with steel would (again IMO) be quite obvious as a Band-Aid solution, However.... If you look @ PL1s spreadsheet, Fig#6 if recessed back a bit would allow for a steel insert panel on the front, (would leave a bit of overhang also but you get the idea right? would give it a fun interesting intended metal/wood look, and finally #3, +1 on the bondo.... Hope this turns out awesome like your last one. ;D
Title: Re: How can I round this sharp edge?
Post by: DaOld Man on September 16, 2017, 05:41:52 am
Thanks Jenn, naw I aint dead yet but sometimes I wonder what them buzzards circling my house are up to. LOL.
I have since used bondo on the scratches and its looking pretty good, but I need to go back and apply some more, not quite warm and fuzzy about the texture yet.
I havent worked on this project at all in over a week now. I worked 12 hours each last Saturday and Sunday, then 54 hours through the week after that. (Im getting too old for this bovine excrement).
I'm off this weekend and they are saying the weather is going to be good so I'm hoping I can get some more done.
Title: Re: How can I round this sharp edge?
Post by: jennifer on September 16, 2017, 08:59:28 pm
      Glazing putty is a lot easier to use, and allows for small bit of flex without cracking, it mixes like putty but sands easier (more fore finish coat and pinholes).... Buzzards like cold pizza, go out in the middle of the road and wave some around, and lure them in. (giggle) >:D