Thread: Hafco Disc Sander

Ok, tried removing the screw but it's stripping so forget that option.

I can either turn the thing on and scrape the disc down until it's true, or stick a thin wooden disc on it and turn that down to true. I'm concerned if I do this it will unbalance the disc though and cause vibration. Any thoughts?

I doubt I can return it for warranty now that the screw head is stripping away. If I'd realised how difficult it would be to remove I'd have left it. I'm certain if I could remove the screw I could reseat the disc and all would be well but at this point I'd have to drill it out.

I'd return it regardless the head of the screw stripped because you were trying to rectify a problem. One of course that shouldn't be there.

Good point. I get the impression after googling the problem that I might go through 3 or 4 machines before I find one that is accurate. Apparently this is rather a common issue with generic disc sanders, and the wobble I'm seeing may actually be considered within normal specifications in any case.

I've tried it and it does work effectively. At the speed it runs at, the wobble isn't as noticeable. If it does get on my nerves it would take very little effort to square the disc by either building it up with a timber disc or scraping away some of the aluminium. I'm concerned that if I build it up with timber, the glue may fail at some stage when it's running. Scraping the aluminium away will weaken the disc. Taking it back will likely end with me spending more money on a machine that is accurate out of the box, rather than taking pot luck on a cheap machine. I guess that's the nature of cheap tools. If I'd spent hundreds on it I'd be upset, but it was a VERY good deal.

If I decide to glue a disc of wood on and true it up, can anyone recommend a good glue? Preferably one that will handle the obvious heat build up that these machines get while running?

In my opinion, Id return it and get another, it should be fine out of the box, Ive had the woodfast disc sander for 3 years now and its never missed a beat and was fine out of the box, and that should be the same even with a cheaper version.
Also it sounds like alotta work to glue a piece of wood onto the metal face plate and then turn it till its perfectly flat with the chance that something could do wrong and you damage the machine more... also I assume you going to be using the velcro system to replace the discs etc and that sticks directly onto the metal face plate.

You have to remember when looking online about problems with tools or products that even if there are a few threads around various forums talking about a problem,you have to remember the large number of people who dont have problems and never needed to actually post anything online about an issue.

If you have an issue about getting another dud, why dont you ask to spin up the replacement at the store to make sure its working to your expectations, it cant hurt to ask.

Ok I might give it a go. It's so frustrating because I can actually see what's causing the issue but the central screw simply won't budge. If I removed it I could absolutely square the disc on the shaft. 5 minute fix and no travelling to archerfield.

Hopefully h and f will let me return it, stripped screw and all. If not, I've decided to drill the screw out and do it that way. It's a pretty standard size so replacing it will be easy.

Success! I called Hafco today and confirmed at least that the screw is DEFINITELY not a left hand thread, so I was at least turning it in the right direction. Found a slightly bigger bit and gave it a crack and miraculously it caught and the screw gave way. Screw has come out now and I didn't have to drill it out.

I haven't removed the wheel yet (too late for today, maybe tomorrow) but it appears outwardly that as soon as I removed the screw and washer, it is spinning closer to true. It isn't exact but a lot better than it was.

At a glance it seems the spindle may be slightly off, but even if it remains as it is I've taken the wobble factor down by well over half. I suspect it may be within normal tolerances now.

If I find the spindle isn't quite straight I'll return it, however if it is I'll just try reseating the disc onto it and get it as square as possible.

Lesson learned: Always check before leaving the store. Although I do love a challenge....

Update: spindle appears straight. Washer is extremely inaccurate (too thick on one side) so I've discarded it and replaced with a new washer. It still has some run out but it's not too bad. If I wanted to I could just sand the high point down until it was ok.

Googling this has shown it isn't uncommon, even in some of the expensive models. What is considered a normal tolerance for these discs? Are we just being too picky or are manufacturing standards getting worse?

How far was the runout you are talking about? and what is it now?

It's hard to measure because I don't have a dial indicator but it was originally over 1mm. It's now far less, a bit under 0.5mm. This is measured as near to the edge of the disc as possible.

I used a very inaccurate way of measuring this but basically put a block against the wheel clamped to the table at high point, spun the disc to low point, inserted thin shim of approximate gap size into gap, measured said shim with calipers.

An update for anyone who may be interested.

I've looked into this some more and it seems the runout is considered excessive, so I've started sanding the disc down to true it.

The velcro backing will likely make absolute accuracy impossible but it needs to be closer than what it is. The spindle is true, as is the disc. When I fasten the disc to the spindle it throws it out of whack. I've replaced the washer and it helped a lot so sanding it should just about do it.

I looked at a range of sanders before getting a Jet, definitely seemed to have more runout in the cheaper machines however the velcro adds some inaccuracy anyway. If you advance the wood slowly the job will get done but you won't use the full area of the sanding disc!

The jet one looks nice but their prices are getting very high now.

I've reapplied velcro to the disc and it looks a lot better. I need a new sanding disc now to test it out but the wobble seems virtually gone, or at least negligible.. I would have sanded more of the disc away but it was starting to get unbalanced and this will hopefully be a nice compromise between two different problems. I'm not using it to accurately shape things, but rather to just flatten an edge down and remove saw marks.

I think next week you'll be very happy and have forgotten the little runout problem, congrats on your efforts!

I have an old Hafco Disc/belt sander that I acquired 2nd hand. Must have been lucky. it had no run out.

The folks at Hafco Brisbane are very good to deal with.