Bandsaw refurbishment - advice needed!

[RichardSmith]

Hi Wood Experts,

I recently acquired a Dewalt DW3401 bandsaw from a neighbour who is downsizing and no longer has the space to keep it in his new garage. I've removed the blade, disassembled, oiled and reassembled all the moving parts, but while I'm no bandsaw expert (this is the first I've owned and the sum total of my knowledge has been gleaned from Steve Maskery's DVD series) there are a few things that didn't look right to me that I wanted a second opinion on before going further:

1. Both the top and bottom wheels have no rubber tyres on them, and seem to have been wrapped with some sort of plastic tape that is torn in places and uneven. The wheels have a raised lip on each edge, and the tape sits below the level of that lip, and in some places rides up onto the lip. I'm assuming this is the result of someone bodging a fix when the original types expired, but is this some sort of alternative approach to bandsaw tyres that I'm not familiar with? Should I be looking to purchase some replacement tyres? I've seen suggestions about using cork such as that sold on the Scott and Sargant website that seems significantly cheaper - is this a viable option?

2. The adjustment screw that alters the angle of the top wheel doesn't look original, and even when everything is tightened there is some play in the top wheel about a vertical axis. Does anyone have a similar machine that they could take a couple of close-up photos of so I can see what this assembly is supposed to look like?

3. When I switch the machine on, with no blade installed, the motor seems to run fine but I get quite a bit of vibration. Is this normal for a bandsaw of this type, or should I be checking whether the lower wheel is unbalanced in some way?

While I'm happy to attempt to fix these problems, and indeed relish the challenge of getting this machine back to its best, I guess I'm wondering whether this will be worth my while or if this machine is a lost cause and I would be better saving for a cheap benchtop bandsaw like the Scheppach Basato 1 instead?

All advice gratefully received!

Cheers,
Rich

 

[Steve Maskery]

Hi Rich

the sum total of my knowledge has been gleaned from Steve Maskery's DVD

What more could you want?
OK, I admit it doesn't go into rebuilding an old machine.

First of all, it probably is worth sorting out. My first bandsaw was that model and it is OK. The fence is rubbish but the rest is OK. Not great, but OK.

1. Are the wheels alloy or plastic? There was a phase of them using polypropylene bandwheels and they were truly awful. I sent two pairs back in the first few weeks and eventually got them to supply proper ali ones. That bandsaw is still running nicely 25 years on. My brother has it.

It sounds like the tyres are long gone. You must get replacements. But they are not expensive. Eric the Viking recently bought some for his (SIP, I think) machine from Axi for just £3-something each. Give them a shout.

2. I can't remember what the tracking mechanism looks like on those, but there is supposed to be adjustment, so I wouldn't worry about that at this stage. Can you post a pic of what looks like a replacement, maybe that will jog my failing memory?

3. What parts vibrate? You can check the balance of the wheel easily. Remove the blade and drive belt and spin the wheel by hand a few times. Does it always stop in the same position? If so, it needs balancing. If not, it's OK.

S

 

[RichardSmith]

Hi Steve,

The DVD is excellent - just need a working bandsaw before I can start applying all I have learned!

The fence being rubbish shouldn't be a problem, as my secondhand model is missing it's fence! If I can get it running well my plan was to construct a rail and fence from mild steel - I have a similar project underway to replace the fence on my tablesaw.

1. The wheels are alloy. I'll give Axi a call as you suggest - the prices I saw on various websites made me think I would have to pay £20+ per tyre, but hopefully I can get them for significantly less.

2. I'm struggling to get a clear pic, but what looks like a replacement is basically just an M5 bolt with a square head (the square head is all that is visible on the outside of the case, no adjustment knob or anything), with 3 square nuts on the inside. One of these locks the bolt to the case (it looks like the case has a recess for a hexagonal nut, which is one of the things that has made me suspicious) and the other two lock the arm connected to the top wheel in place. This system seems to do a good job of keeping the arm a fixed distance from the case, but I'm worried that the original mechanism also played a role in preventing the arm twisting, which the current system does a poor job of.

3. I removed the belt, and when firing up the motor it runs almost silently (I had to peek inside to check that anything was actually moving) so the drive pulley would seem to be ok. The bottom wheel wasn't spinning freely, but after a good clean and a little WD-40 I have it spinning reasonably well (it still doesn't rotate silently and take ages to come to rest like the top wheel). The bottom wheel definitely seems to be out of balance, as after 20 or so spins all my pencil marks are in the same quadrant of the wheel. Upon removing the tape from the top wheel, it has a 5" section of the rim missing and is therefore significantly out of balance. Any advice on how I should go about balancing up the two wheels?

Thanks,
Rich

 

[Eric The Viking]

To be fair, I *guessed* that tyres for the Axi machine would fit mine. And they did.

Meanwhile... DeWalt: Miles Tools and Machinery Centre in Yeovil keep DW spares, and have an exploded diagram/parts list for your machine that I just found on-line via Google:

.

The tyres you need are probably #29 above (assuming the wheel is the same diameter as on yours). Your exact saw doesn't seem to have tyres listed...

... but the wheels are already crowned, I expect, inside the rims. Thus any tyre that's the right overall circumference will probably do, as long as it's close to fitting. You might even risk cutting a larger one and glueing it back together to fit. Mine have no glue, just the 'elastic band effect' to hold them on. Superglue with activator, possibly to join the ends together, or bicycle puncture repair glue?

Miles Tools have been very helpful in the past when I've called them. Get the diameter of the wheel, and give them a ring, but it's best done after lunch on a Wednesday or Thursday, when things are quietest

If you get a tyre, clean the wheel thoroughly before fitting it: no lumps of old tyre; no sticky stuff from that tape. Tyre perishing is partly biological, I think, and remnants will encourage the new one to perish faster, never mind make the blade wobble. Oh and when you find it does fit, buy two more!

E.

 

[Lons]

Hi Rich

I have the 3501 which is the variable speed version whilst yours the 3401 is 2 speed but otherwise identical.
I bought mine 20 odd years ago as I couldn't afford the startright model I wanted but it's served me very well indeed with virtually no problems.

It doesn't have the largest capacity, isn't the most rigid, (mine has plastic wheels), fence is poor etc. but with a decent blade and a little care, it isn't a bad machine and worth restoring imo. From memory, they were around £395 retail all those years ago!

I do have the original 2 booklets supplied, instructions / parts list and happy to scan or copy them if needed.

regards
Bob

 

[RichardSmith]

Eric - many thanks for the tyre advice, I will try Miles if I don't get anywhere with Axi. With regard to cutting down larger tyres, I wondered if it would be just as good to buy a roll of rubber strip from these guys: http://www.rubber-strip.co.uk/ and glue that to the wheels? The only thing I don't know is how thick the rubber strip should be - I'm assuming I would want it to come flush with the rim or slightly higher to prevent the blade catching the rim?

Lon - Good to know that a similar model has worked well for you over such a long period! Copies of the booklets would be great if you have the time to scan them, as would a close-up photo of the top-wheel adjustment mechanism.

Thanks,
Rich

 

[MickCheese]

I wouldn't even attempt to balance the wheels until the tyre are fitted. (sorry not trying to teach you to suck eggs and all that)

I have the Elu equivalent and its a good little saw, persevere.

Mick

 

[Eric The Viking]

Several follow-on comments:

1. I think the point I was clumsily trying to make about Axminster is that they don't sell DeWalt bandsaws. I guessed about mine, based on what I know about mine (SIP) and Axminster's product lines. It's not really fair to ask them to sell you stuff for completely different machines, unless you're happy to take the risk and are certain of the fit.

2. I'd be *extremely* surprised if they have anything to fit, as I don't think their saw range recently has gone down to that size of wheel. I'm often wrong, but see (1) above.

3. Regarding rubber strip: Does yours look like this in cross-section?

If so, you need the diameter of the wheel and the space between the flanges, to get the tyre dimension. The tyres are just rubber (or similar artificial material). If you can get the diameter of the belt, you can cut the tyre to width with a jig. You might even get away with an inner tube from a child's bicycle, at least for the top wheel, as that tyre gets little stress compared to the other one. If as diagram above, you want a FLAT profile tyre, not a crowned one. The crown (which is absolutely necessary) is provided by the wheel itself - the tyre stretches over it.

As I mentioned, if fitting a 'foreigner' subtract a bit of diameter (say 10%) to get the right fit. If it is a stretch-over, type I wouldn't glue it, but use something like a pair of very clean cross-head screwdrivers as tyre levers. Talc or tyre chalk will aid the sliding, without attacking the rubber.

I suggest you get the measurements, then try Miles first. If there have been several iterations of similar DeWalt bandsaws, they'll probably all have the same tyres, or nearly so. Also, try looking on-line in the States - not for purchase as it's probably too expensive, but for information.

Hope that helps a bit.

E.

 

[RichardSmith]

Mick - thanks for the advice, I'd seen suggestions both to balance before putting on the tyres, and after, so it's good to have a definite path to follow. No need to worry about teaching me to suck eggs - Steve doesn't seem to have a DVD on that, so I know even less about it than I do about bandsaw repair !

Eric - turns out Axi were prepared to recommend me a replacement tyre - their AWHBS310N has the same diameter wheels, so I've ordered a couple of those tyres for £3.30 each. My wheels look just like the ones in your cross-section diagram. I've read conflicting advice regarding whether to glue the tyres on - some horror stories of tyres and blades flying off and others saying glue isn't necessary. I'm hoping that as long as the tyre is difficult to stretch over the rims I should be ok, and the flanges should at least stop the tyre coming off under load.

Thinks,
Rich

 

[Lons]

Lon - Good to know that a similar model has worked well for you over such a long period! Copies of the booklets would be great if you have the time to scan them, as would a close-up photo of the top-wheel adjustment mechanism.

Thanks,
Rich

Shouldn't be a problem Rich but might be the weekend before I can sort it out. send me a pm with your email address or to bob(dot)lonsdale51(at)btinternet(dot)com

Bob

 

[Eric The Viking]

Mine weren't glued on. I haven't glued the replacement tyres, either. It's not going at great RPM, anyway.

 

[RichardSmith]

Many thanks for all the help and advice from everyone so far. Thanks to Lons I now have a copy of the original manual and photos of the top wheel adjustment mechanism, and understand the modifications that had been made, and have ordered a couple of replacement parts from Miles Tools to get it back closer to its original state and functioning.

I spent an hour or two today cleaning the bandsaw wheels with Isopropyl Alcohol, a scraper and a wire brush and manger to remove almost all the glue, epoxy and rubber stuck to them. The replacement tyres from Axi seem to be a really good fit, slotting between the flanges perfectly and stretching tight over the wheels by hand without needing to get the tyre irons out. My bandsaw wheels now look a lot more like what I expected from Steve's DVD! However, I now have a couple of additional questions:

1. My bandsaw wheels have regular raised ridges running across the width of the face in contact with the tyre. I assume these are there to help grip the tyres, but because the tyres have a fixed thickness along its length, when they are fitted the same regular pattern of raised ridges can be seen in the surface of the tyre, meaning that it isn't perfectly round but more like a many sided polygon. My question is - will this cause problems, and should I be trying to cut grooves into the underside of the tyre somehow to match? I worry that if the surface of the tyre isn't a perfect circle the blade will vibrate left and right when running, but perhaps it won't be an issue in practice.

2. With the tyres attached, I'm now in a position to balance the wheels. The wheels have holes with a semicircular cross section at regular intervals around the rim, and I'm assuming balancing involves filling the holes closest to the 'light' side of the wheel. However, I'm not sure what I should fill them with and the process for working out exactly how much weight to add in each position, so any advice on this would be appreciated.

Thanks,
Rich

 

[Eric The Viking]

Before worrying much about either of those things, I'd try running it to see what vibration you get.

1. Finding where any vibration is coming from:

Put a dot of paint or marker pen or Tipp-Ex on the rim, and check if any vibration you get times-in with the revolutions of the bandwheels.

THE NEXT BIT IS POTENTIALLY DANGEROUS: You don't actually need a blade on the machine to get the RPM: assuming the bottom and top wheels are the same diameter, you can run the bottom one (marked-up) to get the RPM on its own - the no-blade speed will be very close to the no-load speed in use. If in any doubt, don't do this.

SAFETY NOTE: Obviously you need to be able to watch the wheels when it's running, and that might mean playing with interlocks, for example taping them or wedging them* so you can run the machine with the casing open. This is dangerous with a blade mounted. ONLY, EVER, DO IT FOR THAT FIRST OBSERVATION. Set the machine up to run properly, as normal, and CHECK IT'S RUNNING PROPERLY FIRST. Then, and only then, open the casing to make your speed observation. As soon as you're done, restore the interlocks to normal.

No part of the balancing needs to be done with the interlocks disabled. As I said, you should NOT need a blade mounted to do this, and it's much better not to have one.

If you think it's bad enough, then take off the blade.

Spin the wheel by hand with a finger resting on the end of the shaft: if you can feel grinding or crunching under your finger, the bearings are iffy/knackered. If you just feel a slight wobble, it's only out of balance. If you want to fix the balance, you need good bearings to start with, otherwise the bearing will define the behaviour, instead of the weight distribution.

2. Actually balancing it

Usually in the factory these things are quickly balanced by drilling the heavy side (no extra bits needed). Mine has factory-fitted steel clips on the rim instead. I'm sure it will help, but it's probably already in pretty good balance (drilling is permanent), unless it's been really clobbered by something.

If you're dead keen, scraps of roofing lead cut into really narrow strips and folded over the casting (or thick copper wire wound round a spoke near the rim) will do. The nearer you get to the centre, the heavier the balance weight can be, but the real advantage of lead sheet and wire is that you can trim them with tin snips - infinitely variable!

There are several processes for motorcycle wheels (Google "static balance" in that context), the most sensitive of which is probably holding the wheel horizontal on a conical pivot, slightly above the wheel's centre of gravity, BUT that doesn't address concentricity (can be a nuisance for bikes!). I reckon for this purpose, it's as easily done with the wheel in situ (but no blade).

Spin it ten times and note where your marked spot stops each time (for the driven bandwheel, take the drive belt right off first). If there's no obvious pattern, it's in balance and can be left alone. If it VERY SLOWLY spins down and always stops near one spot, it's probably not worth fussing with (even if it reverses at the end to get there). If it stops fairly quickly**, reverses quickly, oscillates and always stops in the same place, it's probably out of balance enough to merit attention.

Mark the point that ends up at the top most often, and add weight on that radius. If you wrap round a spoke, mark the distance out from the centre, as the nearer the rim the greater the effect. Adjust until ten goes don't give much consistency. If you secure your weight with a blob of Araldite (say), don't forget a balancing blob diametrically opposite!

I don't think the ribs will matter - the tyre is compressible. It will compress more over a rib. If you think it's causing vibration, you could file them off, but it's a bit of a faff. The top wheel doesn't need any at all, as it's not pulling the blade round.

Hope that gets you started.

E.
*or clamp a block of wood to the frame to simulate the closed door.

**Theoretically, of course, an out of balance wheel will take exactly the same time to become stationary as a balanced one - it's the bearings' friction that determines it, not the balance - but in practice the time it takes will be a measure... I think !

NOTE: I edited this a few times to try to describe a safe procedure for checking where vibration comes from. I'm not happy it's idiot-proof even now. If you don't feel comfortable maintaining moving machinery, don't try the RPM measurement at all, just do the balancing.

 

[RichardSmith]

Hi Eric,

Thanks for the detailed balancing advice. I checked the vibration without the blade in place, and it was pretty bad and appeared to be timed with the rotation of the bottom wheel. When I run with the drive belt removed there is no vibration at all, so I'm assuming that means my bottom wheel is out of balance. Spinning it ten times results in it settling consistently in one place and on most occasions 'falling back' to this position. The top wheel has sustained some damage to the flange on one side, possibly due to a blade slipping off when running, and about a five inch section is missing, and as expected this missing section is always at the top after spinning this wheel and as it settles I get a pendulum effect.

I tried to describe in my previous post the balancing holes around the rim (at least that's what I think they are), but here is a photo:

I was assuming there was something I should be putting in those holes to balance the wheel, which might be better than either drilling or attaching additional weights, but can't figure out what... I wondered about filling with flexible filler, but getting the exact right amount seems a bit hit and miss, and I'm not sure it would be heavy enough to correct the seriously out-of-balance top wheel.

Thanks,
Rich

 

[Eric The Viking]

The bottom wheel and its bearings take the bulk of the wear. Did you try the check to see if you can feel a worn/broken-up bearing grinding? I think those holes are a function of the casting process, rather than anything more useful.

Given the weight of it overall (i.e. relatively massive for its diameter), I'd drill a small hole in the flange/web, say 4mm, on the radius that settles uppermost, fairly near the inner edge of the web, and fold some lead sheet over it, held in place with washers, a bolt and a nyloc nut (or just Loctite). You can easily trim it to exactness with tin snips. It won't shift out of place, as centripetal force pushes the flange into the fold of the lead. To get a rough idea of how much, use a bulldog clip to hold the lead in place temporarily.

I doubt the top wheel is a total disaster, you might balance that in the same way, but I would check it out carefully for bearing damage and cracks in the casting near the damaged area. As you suggest, I also assume it's the result of a blade coming off/breaking, and the sudden change of tension might have hurt something. It also might have pulled it out of true, so check both for front-to-back wobble. If they do, assuming the bearings are sound, then replacement is probably the only option.

Cheers,

E.

 

[Lons]

I'd drill a small hole in the flange/web, say 4mm, on the radius that settles uppermost, fairly near the inner edge of the web, and fold some lead sheet over it, held in place with washers, a bolt and a nyloc nut (or just Loctite).

The alternative is to nip in to a local tyre fitting centre and beg a few of the self adhesive wheel balance weights.

I would stick one temporarily to the wheel with selotape which weighs virually nothing and clip bits off until you can balance the wheel by hand then stick it properly with the adesive tape supplied already fitted to the balance weight.

Bob

 

[Eric The Viking]

Lons' idea is much better than mine!

 

[thedax]

Hi Guys I know this thread is a couple of years old but I have a problem with the adjuster on the top of the machine, I believe its a Elu 3401 not sure how you tell I think the previous owner put the wrong size blade on it as the last blade snapped and the adjuster will loosen but not tighten just clicks. first off how does it come apart !!?? Been trying for ages and I am no afraid I will break something as the usual pulling and pushing is getting me nowhere any ideas how to strip it please. thanks guys

 

[Steve Maskery]

That was my first BS. Nice little machine, IIRC.

If it is clicking and not tightening, it sounds as if the thread is stripped. I can't remember the constructional details of it, but on most BSs you can remove the adjuster just by continuing to slacken it off. It sits in a moulded hollow in the frame and an alloy leg behind kicks the wheel back and forth as you adjust the tracking knob at the back.

It should take a 1/2" blade happily enough. Wider than that and I think you are asking a but much.

 

[thedax]

thanks Steve Ive unwound and unwound just spinning and not moving but if thats how it comes a part I will work on that area, I have just bought a a 5/8 blade hope its not too much for it 82 1/2 5/8 10 tpi