Delta model 31-396 edge sander ( belt troubles..)

larry merlau

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Location
Delton, Michigan
Ok here is what i am incurring, i wanted to to sand the edge of a board and be square when done both in thickness and width, but with the belt being bubbled or not tight against the platen its not going to happen.. even on the long way its going to sand a concave area..


woodshop pic 230.jpgidle lft
woodshop pic 231.jpgidle ctr
woodshop pic 232.jpgidle rt
woodshop pic 233.jpgleft platen
woodshop pic 234.jpgctr platen
woodshop pic 235.jpgrt platen
woodshop pic 236.jpgrun left
woodshop pic 237.jpgrun ctr
woodshop pic 238.jpgrun rt

if anyone has a edge sander and can help i am all ears,, have talked with a couple of you and it seems i need more belt tension, but this thing tilts the head to make it oscillate and therefore it basically is loosening up and the tightening back down,, to me the belt should be flat against the platen when running, in order to sand flat anything ,, as it is the part gets sanded before it ever puts pressure against the platen.. if you or your neighbor has one of these test it out for me or see how theirs works.. becasue this one seems to have issues or the operator needs to read some tech manual:)
 
I will do some pics after work and post them . . . Later that day . . .

Before you drive yourself nuts, pull the belt and put a straight edge on the platen to assure it is flat.

Here is the spacing from my add-on table to the belt under tension. All my belts stay flat against the platen when tension is on however, they were all bought new from Klingspor except for the Klingspor belt that came on the machine. The platen has graphite material on it. I have some 6" peel and stick graphite cloth but don't recall where I got it. If your machine does not have this I can dig up the source. It was pretty inexpensive.

Sander Pics for Larry (1).jpg


Here's an overall shot. The table comes off with a spin-tite to loosen the recessed bolt heads. The little white bumps on the left edge are nail-on feet that keep it off the concrete when I store it over by the spindle sander. Since I leave the auxilliary table on most of the time, this may have been overcautious :eek::

Sander Pics for Larry (2).jpg Sander Pics for Larry (3).jpg

I used the t-nuts supplied for an accessory fence with the sander. The fence is a laminated pair of 3/4" BB ply strips milled square and attached with a fixed through bolt at the platen end and a "loose" through bolt at the operator end for adjustment. I just hold a machinists square against the paper/platen and square the fence to that.

Sander Pics for Larry (4).jpg Sander Pics for Larry (5).jpg Sander Pics for Larry (6).jpg Sander Pics for Larry (7).jpg

Here's a shot of the tension on and off as well as a shot of the motor mount (the oscillator is at the idler end on this model).

Sander Pics for Larry (8).jpg Sander Pics for Larry (9).jpg Sander Pics for Larry (10).jpg
 
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More pics . . . . Here's a shot with the back guard off, you can see the oscillating mechanism in the lower right of the pic. There is also a shot of the really simplistic adjustment mechanism for table height and belt tilt.
Sander Pics for Larry (12).jpg Sander Pics for Larry (11).jpg

Here's the tension on and tension off view from behind:

Sander Pics for Larry (13).jpgSander Pics for Larry (14).jpg

You can see that there is only about 1/2" of travel between loose and tight on the belt but, it seems adequate. When tight there is a reasonable bit of motion in the handle so that as the belt stretches, tension is maintained.

Sander Pics for Larry (15).jpg

I hope some of this might help with your troubles.

P.s. Here's how I quickly set the table to platen gap and square the fence when I re-install the table.

Sander Pics for Larry (16).jpg Sander Pics for Larry (17).jpg
 
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thanks glenn for all these shots and your trouble.. on mine the oscillator is on the motor side, will do as you suggest and replace the belt.. also will take some pics of my setup later.. thanks again..!!
 
Have you tried a new belt? I have noticed that as belts wear they stretch and can "puff" out in the middle. I have a homemade edge sander, it does not oscillate but I built it with the platen just proud of the drive and idler rollers to ensure that the belt stays flat against the platen. Is there an adjustment for the platen position (out /in) or can the rollers be adjusted? I would check with a straight edge to see if the rollers are behind the plane of the platen and if they aren't start looking for places to make adjustments. If there are no adjustments to be made adding some graphite cloth will help move the platen plane out.
 
well thanks to Dave and Glenn for there help in this and i was able to get this setup and running as i thought it should be.. here is where i am now and that seems to be close enough for what this tool is expected to do..
sander fix pic 001.jpgsander fix pic 002.jpgsander fix pic 005.jpg
sander fix pic 003.jpgsander fix pic 004.jpgsander fix pic 006.jpg

now a couple questions first,, how long before the belts go bubbly, and 2, should i detention the belt when not in use
 
well thanks to Dave and Glenn for there help in this and i was able to get this setup and running as i thought it should be.. here is where i am now and that seems to be close enough for what this tool is expected to do..
View attachment 80326View attachment 80327View attachment 80330
View attachment 80328View attachment 80329View attachment 80325

now a couple questions first,, how long before the belts go bubbly, and 2, should i detention the belt when not in use

It will last as long as the grit is good and I never did loosen mine and never had an issue :thumb::wave:
 
Larry do you think it might have been caused from the conditions where the sander was stored before we picked it up? Moisture in the air?

that did enter in to my head charles,, probably was alot of it.. we will see how it works in my conditions:)

I'm hoping Charles is right. I have not had mine all that long but, I have worn out a couple of the finer belts (or worn them to where they are not suitable for what I use "fine" belts for). I have seen no bubbling. I still couldn't tell from the pics Larry but, if your platen doesn't have a graphite pad on it, this stuff is pretty reasonable. It will make the belts run cooler by lowering friction quite a bit.
 
I can't say how long belts last before bubbleying, if that's a word. I never really paid attention to life span, I've just noticed that the old ones are usually bulging slightly. It may be due to the crowned roller stretching it more in the center of the belt. I would guess that you have a crowned roller. I know the belts track much much better with even a slight crown.
 
glenn, i do have the graphite layer on the platen. and jay, i understand bulging belt in old age but in my case i am shrinking:) everything is gettin thinnner my hair and the rest of me.. dont dare go ut in high winds anymore for fear of being wizked away with toto somewhere:)
 
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