I just discovered that I have a problem with my wide belt sander. I think I know what the problem is as well as the solution, but it wouldn't be the first time I've been wrong so thought I'd get a second opinion.
So I run a 77' 43" Timesaver with an 11-1/2" rubber covered drum, no platen. I was sanding a 40" wide 1-1/2" thick oak top yesterday and seemed like the machine was working too hard. Several passes at the same height would still tax the machine. After a full hour of sanding this beast I finally got it flat....or so I thought. Looking at it standing on edge I thought I saw a slight bow in the middle. Grabbed the straight edge and sure enough the middle was a bit high. Worse yet it's high on the bottom as well! Maybe a 16th on each side. So I figure either my drum is flexing, (unlikely), or my machine is showing signs of close to 40 years of use....I think my table is dished!!!
Now it's a great machine and a real workhorse, but it's up there in age. Pulling the table, (assuming it is dished for now), having it machined flat and re-installing is going to cost some cash. At that point I'd have to buy a new feed belt as well. Not sure if it's like an old truck where at a certain point your throwing good money after bad? Or if it's worth it since an affordable entry level sander won't come close to the quality? I guess I'm just looking for advice from the group on how to choose a direction.
Jeff, is this something that suddenly showed up, or you just noticed it? Has the sander been producing consistently sized parts across the bed width?
It would seem that the problem must be due to a worn contact roller, a worn conveyor belt or a dished table. Can you loosen the conveyor enough to get a straightedge under it to check the table?
I guess you are in the best position to evaluate the costs and benefits of tearing down and rebuilding vs. new. I will say that when we were in the same position we went with a remanufactured Sandingmaster from Woodshop Specialties in Rutland, VT. It cost us about as much as a new SCMI at the time, but we felt we were getting a very solid and simple machine. It might be worth a call to the owner, Mike Shahan. He is a very good tech and a straight shooter and probably has worked on old Timesavers like yours. I think he might give you some good perspective on the repair vs. new decision
The drum and conveyor are both wear prone . No matter how good your operator the parts always overlap in the middle so the conveyor wears more there. The drum can too over time.
I absolutely hate dressing drums inside machines. You put sandpaper/wood on your worn conveyor and grind that wear pattern into your drum. No one ever levels the drum first. They end up cone shaped. Once you remove rubber the spin balance is lost and it starts to chatter.
If you see multiple passes at the same height unloading more pressure onto the product then you are most likely taxing too fine a belt. Many passes with a fine belt are very bad for color consistency and quality. It is much better to grind a surface with 80 or 60 grit than to do 10 more passes with a 150 grit. Much less pressure accumulation.
I suggest checking the flatness under the conveyor, but I bet simply dressing the conveyor will fix you right up.
Hi Adam, I was using an 80 grit belt to flatten the panels. Except it just wasn't flattening them as I expected.
If I were to try and tune up the sander do you have any advice where to start? You say you don't like truing the drum in the machine, so do you send it out to be trued? There's no way to inspect the table without removing it and the belt. At which point I'd want/need to install a new one, existing belt is pretty thin. Then if the table is out of flat I'd have to deal with finding a place that could grind it back to flat. After which I'd have to re-address the drum which is mostly flat across it's width, but does flare out roughly .004 at the very ends.
Trying to come up with a game plan as it seems as though it's an all or nothing type of situation.
Has there ever been anything done to your rubber drum, dressed, changed out, ect? If not then you have a few options. 1. you can remove the drum and send it out to be ground and dynamically balanced (balancing is critical). I would recommend replacing the bearings at the same time. OR 2. you can attach 2-1" thick pieces of MDF together along with a 80 or 60 grit sandpaper glued to it and dress your contact drum while in the machine. Why so thick of a dressing board? Because if you are unsure of any wear that may be in your bed plates, the thickness of the two pieces of MDF together will be rigid enough to minimize the wear in your bed plates by not allowing the dressing board to bend/conform to the wear pattern in the plates, provided you are using light sanding pressure to dress the drums with. Our website has a section on how to dress a contact drum that may help as well.
FORUM GUIDELINES: Please review the guidelines below before posting at WOODWEB's Interactive Message Boards(return to top)
WOODWEB is a professional industrial woodworking site. Hobbyist and homeowner woodworking questions are inappropriate.
Messages should be kept reasonably short and on topic, relating to the focus of the forum. Responses should relate to the original question.
A valid email return address must be included with each message.
Advertising is inappropriate. The only exceptions are the Classified Ads Exchange, Machinery Exchange, Lumber Exchange, and Job Opportunities and Services Exchange. When posting listings in these areas, review the posting instructions carefully.
Subject lines may be edited for length and clarity.
"Cross posting" is not permitted. Choose the best forum for your question, and post your question at one forum only.
Messages requesting private responses will be removed - Forums are designed to provide information and assistance for all of our visitors. Private response requests are appropriate at WOODWEB's Exchanges and Job Opportunities and Services.
Messages that accuse businesses or individuals of alleged negative actions or behavior are inappropriate since WOODWEB is unable to verify or substantiate the claims.
Posts with the intent of soliciting answers to surveys are not appropriate. Contact WOODWEB for more information on initiating a survey.
Excessive forum participation by an individual upsets the balance of a healthy forum atmosphere. Individuals who excessively post responses containing marginal content will be considered repeat forum abusers.
Responses that initiate or support inappropriate and off-topic discussion of general politics detract from the professional woodworking focus of WOODWEB, and will be removed.
Participants are encouraged to use their real name when posting. Intentionally using another persons name is prohibited, and posts of this nature will be removed at WOODWEB's discretion.
Carefully review your message before clicking on the "Send Message" button - you will not be able to revise the message once it has been sent.
You will be notified of responses to the message(s) you posted via email. Be sure to enter your email address correctly.
WOODWEB's forums are a highly regarded resource for professional woodworkers. Messages and responses that are crafted in a professional and civil manner strengthen this resource. Messages that do not reflect a professional tone reduce the value of our forums.
Messages are inappropriate when their content: is deemed libelous in nature or is based on rumor, fails to meet basic standards of decorum, contains blatant advertising or inappropriate emphasis on self promotion (return to top).
Libel: Posts which defame an individual or organization, or employ a tone which can be viewed as malicious in nature. Words, pictures, or cartoons which expose a person or organization to public hatred, shame, disgrace, or ridicule, or induce an ill opinion of a person or organization, are libelous.
Improper Decorum: Posts which are profane, inciting, disrespectful or uncivil in tone, or maliciously worded. This also includes the venting of unsubstantiated opinions. Such messages do little to illuminate a given topic, and often have the opposite effect. Constructive criticism is acceptable (return to top).
Advertising: The purpose of WOODWEB Forums is to provide answers, not an advertising venue. Companies participating in a Forum discussion should provide specific answers to posted questions. WOODWEB suggests that businesses include an appropriately crafted signature in order to identify their company. A well meaning post that seems to be on-topic but contains a product reference may do your business more harm than good in the Forum environment. Forum users may perceive your references to specific products as unsolicited advertising (spam) and consciously avoid your web site or services. A well-crafted signature is an appropriate way to advertise your services that will not offend potential customers. Signatures should be limited to 4-6 lines, and may contain information that identifies the type of business you're in, your URL and email address (return to top).
Repeated Forum Abuse:
Forum participants who repeatedly fail to follow WOODWEB's Forum Guidelines may encounter difficulty when attempting to post messages.
There are often situations when the original message asks for opinions: "What is the best widget for my type of shop?". To a certain extent, the person posting the message is responsible for including specific questions within the message. An open ended question (like the one above) invites responses that may read as sales pitches. WOODWEB suggests that companies responding to such a question provide detailed and substantive replies rather than responses that read as a one-sided product promotion. It has been WOODWEB's experience that substantive responses are held in higher regard by our readers (return to top).
The staff of WOODWEB assume no responsibility for the accuracy, content, or outcome of any posting transmitted at WOODWEB's Message Boards. Participants should undertake the use of machinery, materials and methods discussed at WOODWEB's Message Boards after considerate evaluation, and at their own risk. WOODWEB reserves the right to delete any messages it deems inappropriate. (return to top)
Forum Posting Form Guidelines
The name you enter in this field will be the name that appears with your post or response (return to form).
Personal or business website links must point to the author's website. Inappropriate links will be removed without notice, and at WOODWEB's sole discretion. WOODWEB reserves the right to delete any messages with links it deems inappropriate. (return to form)
Your e-mail address will not be publicly viewable. Forum participants will be able to contact you using a contact link (included with your post) that is substituted for your actual address. You must include a valid email address in this field. (return to form)
Subject may be edited for length and clarity. Subject lines should provide an indication of the content of your post. (return to form)
Thread Related Link and Image Guidelines
Thread Related Links posted at WOODWEB's Forums and Exchanges should point to locations that provide supporting information for the topic being discussed in the current message thread. The purpose of WOODWEB Forums is to provide answers, not to serve as an advertising venue. A Thread Related Link that directs visitors to an area with inappropriate content will be removed. WOODWEB reserves the right to delete any messages with links or images it deems inappropriate. (return to form)
Thread Related File Uploads
Thread Related Files posted at WOODWEB's Forums and Exchanges should provide supporting information for the topic being discussed in the current message thread. Video Files: acceptable video formats are: .MOV .AVI .WMV .MPEG .MPG .FLV .MP4 (Image Upload Tips) If you encounter any difficulty when uploading video files, E-mail WOODWEB for assistance. The purpose of WOODWEB Forums is to provide answers, not to serve as an advertising venue. A Thread Related File that contains inappropriate content will be removed, and uploaded files that are not directly related to the message thread will be removed. WOODWEB reserves the right to delete any messages with links, files, or images it deems inappropriate. (return to form)
The editors, writers, and staff at WOODWEB try to promote safe practices.
What is safe for one woodworker under certain conditions may not be safe
for others in different circumstances. Readers should undertake the use
of materials and methods discussed at WOODWEB after considerate evaluation,
and at their own risk.