calcualting length of paper on drum sander

[allan kuntz]

I am just about ready to pull the pin and purchase the cx504 craftex drum sander. I want to convert this to hook and loop and would like to prepurchase the material. Can anyone tell me how many feet of vlecro I will need or provide a formula to figure it out. I know what PI is. The drums are 6" x 26" and want to use 3" velcro
Here is what I come up
6" drum x 3.1416=18.85" x 26"=490"divided x 3" width of velcro= 163.36" div x 12 =13.61 ft
Am I close
thanks
Al

[Mike Chalmers]

I am interested in this concept. Do you install the velcro over 100% of the surface area? Doesn't the velcro crush and cause unevenness in the finish?

[Jerry Bruette]

My math says you're close. But are you going to spiral wrap the velcro or are you putting separate strips alongside each other?

[John TenEyck]

If the velcro has much thickness to it you probably need to account for that. We generally used 1/2 the thickness of the material when figuring the wrap distance around something. So instead of your drum being 6" in diameter, it would be 6" + the thickness of the velcro (1/2 the thickness on each side).

John

[Lee Schierer]

For a spiral, you would need to know the diameter and the length of the drum and how many wraps are going to be around it.

[allan kuntz]

Mike I have a 28" shop built drum sander with hook and loop and I have never noticed any uneven spots.
Jerry yes it will be spiral wrapped. I don't want to come up short so I think i will order a couple extra feet just to make sure
Lee the diameter is 6" and the length is 26" and the velcro is 3" wide and i don't know how many spiral wraps it will take
thanks guys
Al

[Lee Schierer]

This Spiral length link (http://www.apogeerockets.com/education/downloads/Newsletter304.pdf) will tell you how to determine the length of material you need. The site is for making your own paper rocket tubes, but the math is the same for what you are trying to do.

Lee

[Yonak Hawkins]

I am just about ready to pull the pin and purchase the cx504 craftex drum sander. I want to convert this to hook and loop and would like to prepurchase the material. Can anyone tell me how many feet of vlecro I will need or provide a formula to figure it out. I know what PI is. The drums are 6" x 26" and want to use 3" velcro
Here is what I come up
6" drum x 3.1416=18.85" x 26"=490"divided x 3" width of velcro= 163.36" div x 12 =13.61 ft
Am I close
thanks
Al


You need to add one extra wrap for the tapers at each end. I come up with 15.7'.

[Dave Richards]

I figured it out graphically in SketchUp and get about 15'6-1/2" with allowance for the taper at the end. Instead of 26 in. of spiral wrap, you'd need 29 in. SketchUp made it simple and fast with no need to do any math. Basically the same as Yonak.

https://farm8.staticflickr.com/7457/16275730398_0e25065688_n.jpg (https://flic.kr/p/qNenBm)

[Chris Padilla]

But math is more FUN, Dave! ;) All those sines and cosines and such...whoo hoo!!! :D

[glenn bradley]

Doesn't the velcro crush and cause unevenness in the finish?

The difference would be like when hand sanding with a soft block versus a hard block. I thickness figured woods with my sander so a hard drum and feed belt are a must to maintain accuracy. This is not a requirement for everyone.A flexible abrasive will leave an uneven surface when sanding materials that have soft and hard characteristics like red oak, fir, etc. However, it would be no different that a ROS with a medium pad on like materials so if you have had no trouble there in your work, I would not be concerned. Some drum sanders offer a flap or brush option to sand without greatly altering the presented surface so this can be specifically desirable depending what you are doing.

[Dave Richards]

But math is more FUN, Dave! ;) All those sines and cosines and such...whoo hoo!!! :D

Chris, that is true. Math can be kind of fun especially with all those trig functions. :D

[allan kuntz]

Thanks Dave that's what I was looking for. Math might be more fun but for some one who doesn't understand what all those guzintas are for. This sure made it easier. After all isn't that what these forums are all about
I just ran some rings through my shop built hook and loop drum sander and after checking 9 rings with a light and a straight edge some sides were flat and some were not.
If i do purchase the CX504 I will be trying it first without the hook and loop
Does any one use a drum sander for flattening rings and if so do they come out perfectly flat or do you still have to flatten them and is your drum sander steel or hook and loop
Thanks
Al