I’m making a headboard out a 8/4 stock. The top of the headboard is an arc. I’ve marked an arc and cut it on my bandsaw, leaving a little material left to remove. I’ve removed the excess material with a drum sander on my drill press. I haven’t been able to get the top of the arc as flat as I’d like.
I’ve been using a 1 1/2 inch drum with 80 grit then 120 grit sleeves and I’ve been running my press at about 400 rpm. I’ve been feeding against the direction the drum turns.
Is there a better tool to use or can you give me some pointers on sanding with the drum sander?
Thanks in advance.
Replies
ZachA,
Why not make a pattern for the arc and use a router to cut the exact shape and then hand sand
ASK
ZachA,
I have smoothed out similar projects with arcs with my Stanley #20 circular plane. It works great and leaves a nice smooth arc. On thinner stock I will sometimes use my router's trim bit with a template.
Of course this solution would require the availability of a #20 or similar circular plane :)
Good luck on this project, there is nothing quite like a nice thick headboard with nice accents.
It's so much easier to get a smooth convex (outside) curve than concave curve. I make a curved sanding block for the inside curve to remove the little humps from the OSS. Use the largest drum possible on your OSS.
Hi Zack , Another way would be to use an edge sander , if that is not an option then a belt sander clamped down to a table on it's side will do a great job. IMHO the small drum sander is the wrong tool for the scale of the job you are doing.It would be like trying to sand a gymnasium floor with a 4" sanding disc attached to a drill motor , not the best application for the task .
good luck dusty
Zach
My preferred method for arcs is to cut a pattern with 1/2"or 3/4" MDF. Use a jig-saw or BS. Cut about 1mm to 2mm outside the actual line and then take the MDF down to the line with hand tools and sanding. If you foul up terribly, you are out little with MDF. Start over.
Once you have the perfect pattern, place it on top of the panel to be cut and clamp it. Use a over-head router pattern bit. The over-head bearing follows the perfect pattern on top and you get a perfect dupicated "living copy" under-neath. If you think you might duplicate the project, keep the pattern. If not, it becomes fodder for jigs and fixtures.
Have a good day...
sarge..jt
Ditto on Sarge's method. A palm ROS in a deft hand does a good job of fairing the curve. Use the largest OD pattern bit you can since it's bearing will be less effected by any imperfections in the pattern. Also watch the grain runout. Depending on the severity of the curve and the runout parts of the arc may need to be climb cut.John O'Connell - JKO Handcrafted Woodworking
Life is tough. It's tougher if you're stupid - John Wayne
Thanks, Sarge. I made a MDF jig. Then I made the cut on my bandsaw and trimmed the stock with my Router and a 1/2" straight bit and the MDF jig. Works like a champ!
Zach
Zach
Yes it does. Register that one and you'll be the one answering the question next time it's asked.
Regards...
sarge..jt
Put a 1/2" straight bit in your router. Make a trammel long enough for the radius. Fasten headboard down with clamps. You probably have to fasten one end of the trammel on a scrap board if the radius is larger than the headboard.One way to do this is to set up a pair of horses with three 2x4's screwed down to the horses.Lay headboard down on 2x4's and fasten trammel at the radius length on the middle 2x4.Make sure nothing slides around on you, headboard is clamped down , router bit is long enough to clean up in one pass.
mike
Zach,
I typically use a fairing board to finish convex shapes. Boat builder use fairing boards to (you guessed it) fair the shape of the hull. In your case all you need is a 2-3" wide piece of plywood or solid wood that can be bent to your desired shape. Put a strip of adhesive backed sand paper on one side and 2 handles/knobs on the other side and you should be able to fair the curve inside of 15 minutes. If I had several to do I would consider pattern routing it but for just one its not worth the effort.
Tom
Edited 11/7/2003 3:43:14 PM ET by TCALISTO
Belt sander. has a larger base than that drum.
Routing it can be a simple task, 8/4 will need low RPM's though. Make a pattern or make a jig that holds the router that you swing an arc with. I make curves all the time and I use both applications. You can figure the arc very easily too. You just need a place big enough to fit the jig. All kinds of materials can be used to make the jig also, then you will always have a tool that can be adapted to ANY project. Good luck....................
Last but not least a circle plane and fairing it will do also as described before in the forum.
Vine,
you said You can figure the arc very easily too. I'm having trouble with cutting an arc as well, could you explain? It's a very shallow arc, about 1 1/2" per 19", so I'm going to use a template. I'm having trouble just getting the arc right for making the template.
Thanks,
DP
Well I would like to say that I know this equation by heart, but I think Einstein said" I don't remember anything I can just look up". I usually have a book called the framers bible with me to tell me things like this when I get in a jamb. I looked for it franticlly this weekend and had lent it to a coworker to look at. This formula is also in a taunton book called, principles of construction I believe. Not sure about the title.
Anyways these two links both have drawings, formulas, and descriptions.
http://www.josephfusco.org/Tips/tip0018.html
This site above has drawings and formulas for both concave and convex curves.
This site below hasd an excell spreadsheet set up so you just plug the numbers in and it gives you your desired information for your arc. This particular site has some other usefull info for anyone who builds musical instruments and has tests one can use to test materials for acoustics. Incredibly informative and thorough I thought.
http://www.ukuleles.com/Technology/calcarc.html
To use the excell spreadsheet just click the link in the site.
I don't want to steal the thunder, someone worked very hard to get all the info on these sites.
You guys got to get a cad program and learn to use it. I am working on a tutorial for Quickcad which will be posted in the next couple of weeks, I hope.
Since every arc or part of an arc is part of a circle you can draw it and find the radius of the whole thing or any part of it.
What I do with such things is draw it on the computer and print in full scale and tape the 8.5 X 11 sheets together. It's great for patterns, marking etc
ASK
Hey Ask, Can you show me how to print out individual sheets to join up as a poster? Stein.
steinmetz,
If you are using Quickcad.
File
Pagesetup
standard page or printer page (set the page size to the same size as your printer uses: example 8.5" X11")
set the orientation (portrait or landscape)
tile (set the number of pages to the size you want the poster: example 2 X 1 in portrait will give you an 11" X 17" consisting of two pages, 3 X 2 will give you 25'5" X 22") The printer will print crop marks and you have to trim each sheet to make the sheets match up so the sizes end up a little smaller. about 3/8" along each edge
Set the margins to 0" along each side of the page.
While you are setting the tiling you should see the little screen to the right increase the number of pages.
hit enter
Depending on how the viewing options are set, you will either see the new enlarged sheet size with a colored background or the drawing area all the same color with a light dotted line where the page is and possibly light dotted lines showing each individual sheet of the printer page size.
I always have a white page with no background color since I sometimes do some drawing wich I don't necessarily want to print.
To set either the all white screen or show only the drawing page
View
options
on the top left of this dialogue either check or uncheck the page box.
If you want to see what the entire drawing will look like after you have drawn something go to
File
print preview
If yu only see one sheet (part of the drawing) hit tile in the upper left
Hope this helps. Let me know. And of course, if you have any other questions I'll be here
ASK
Ask, thanx for the info I don't have Quick Cad right now but I'll Google it up. Sounds like it's just what I need. Thanks again, Stein.
Stein,
Staples usually has it or CompUSA
ASK
Staples it is , thanx much .Stein And thanks to all of you who offered help .Stein Got 10 replys so far.
Zach, If the 'Arc' is a true radious of a circle, then use a circle cutting router jig.
If not (As I suspect,) Go the template route. Stein.
Zach
As a general rule use the spindle sander only for inside (concave) curves. Use a disc sander or belt sander, (one of the combo tools works good) to do straight lines or outside curves. It is quite easy to get a smooth curve with a disc or belt. When doing inside curves on a spindle the way to get smooth curves is to keep the stock moving at all times. Move it fairly fast and take many light passes. Also use the largest drum that will fit in the curve. Check it often and if you find a bump make a few light passes over that area untill it feels smooth then go back to full passes. It takes some practice but will come quickly.
Happy sanding.
Rich
The Professional Termite
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