Another mobile base

[BobL]

I was just going to buy a standard mobile base but I need to move my new 145kg BS around on recycled/uneven brickpaving so I need a bit more height and bigger wheels than the standard bases provide.

So here it is. Angle iron from an old bed frame, some bits of 5 mm thick x 40 mm SHS from the scraps bin at work and the wheels from another old X-ray machine. Total parts cost was $11 for bolts and $7 for a can of blue spray paint.
http://www.woodworkforums.ubeaut.com.au/attachment.php?attachmentid=78359&stc=1&d=1216519580

The base lifts one side of the base and then the other using a simple removable lever, The base is held up by a couple of small bolts that pass through matching steel tags on the base and on the wheel brackets.
http://www.woodworkforums.ubeaut.com.au/attachment.php?attachmentid=78360&stc=1&d=1216519580

Here is the base on the machine with the base down.
http://www.woodworkforums.ubeaut.com.au/attachment.php?attachmentid=78361&stc=1&d=1216519580

Base up.
http://www.woodworkforums.ubeaut.com.au/attachment.php?attachmentid=78362&stc=1&d=1216519580

Seems to work OK. If they get in the way, the wheels,cross pieces and mounting brackets can easily be removed with the base down.

[DJ’s Timber]

Looks good Bob, well thought out and made :2tsup:

[Big Shed]

That is very well thought out, very nifty:2tsup: You got a good match on the colour too Bob.

How hard is it to get the wheels back up, is there much inertia to overcome?

Edit:

Any chance of that big brute of a bandsaw toppling over when you put the wheels up or down?

[Woodlee]

I like it ....I was going to build one for mine using hd castors and screw down feet ,
But I like your idea better.
I think your band saw is very similar to mine ,motor looks the same ,colour is different , mine is a Leda 19".
Mine's still sitting on the pallet that it came on .

Kev

[artme]

Much better and cheaper than anything available commmercially. Great job!:2tsup::2tsup::2tsup:

[BobL]

That is very well thought out, very nifty:2tsup: You got a good match on the colour too Bob.

How hard is it to get the wheels back up, is there much inertia to overcome?

Edit:

Any chance of that big brute of a bandsaw toppling over when you put the wheels up or down?

The lift is only on one side of the saw at any one time so thats only half the weight with each lift, so ~73.5kg. Then the leverage is 3.3 to 1 so that's about 23 kg force needed to lift one side - easy. If needed the lever could easily be made twice as long again.

In terms of tipping over most of the weight of bandsaws is in the base so you have to tip them a long way before they tip. The "lift" direction on my mobile base is also along the longer edge of the base so the chances of tipping are even further reduced. To get the BS around the back of the house I had to wheel it down a short steepish path - I was a bit worried at first by the whole thing went very smoothly and felt quite safe.

[joe greiner]

Best I've seen in a long, long time. And this design can accommodate just about any size wheels. Bed frames may not have metallurgy friendly to welding, but the way you've arranged the long pieces above the supporting pieces eliminates such a concern because all those welds serve for position only. The only precaution I'd suggest for frames 2.0 is to ensure that the vertical bars rely on vertical fillet welds or butt welds for sizing. Transverse loading on fillet welds is inadvisable, and/or forbidden by most codes. Still need those welds, though, for sealing.

Joe

[BobL]

Best I've seen in a long, long time. And this design can accommodate just about any size wheels. Bed frames may not have metallurgy friendly to welding, but the way you've arranged the long pieces above the supporting pieces eliminates such a concern because all those welds serve for position only. The only precaution I'd suggest for frames 2.0 is to ensure that the vertical bars rely on vertical fillet welds or butt welds for sizing. Transverse loading on fillet welds is inadvisable, and/or forbidden by most codes. Still need those welds, though, for sealing.

Joe

Thanks Joe. I have heard about the metallurgical problems with bed angle iron but I have never had a problem with it - maybe the Aussie stuff is different? I have a metal work bench and another angle grinder bench made out of bed angle iron that have been bashed around on a weekly basis for some 30 years and although the welds are as ratty looking as when they were first welded there are no cracks so far.

The 4 big pieces of angle iron that make up the main frame are welded on every side so they are not likely to be a problem especially as 99% of the time the thing will just sit on the floor. The vertical bars are welded right across and form an endcap on their respective SHS piece, so they are welded on all 4 sides of the SHS. I was going to weld on the inside of the SHS as well but I reckon she can take a lot more load than I'm putting on it.

The weakest link in this design is the bearing between the main frame and the SHS axes. The turning connection is a 5/16" tensile steel bolt which will be more than strong enough, but to make it easy to lift I wanted to reduce direct metal on metal rubbing so I inserted a 1" diam x 1/16" thick Telfon sheet washer. This stuff works really well in terms of low friction but I notice that after 12 hours, being soft it has already compacted down under the medium bolt tighteness, and flowed a little, and this has caused the axles to sag a little. I think I will retighten the 5/16" bolt one more time and if that does not work I will replace the teflon with some 1/8" HDPE sheet which is a lot harder.

Cheers

[joe greiner]

The precaution about welding bed angle iron was told to me by a young but retired welding instructor - has something to do with hydrogen embrittlement IIRC. I've had no dramas either, but he merely suggested mechanical connections for overhead support, i.e. don't rely on such welds alone hanging above.

There's something very tough about bed angle iron. Probably a combination of steel alloy and the cold-rolling process. The only way I've been able to drill it is with cobalt drills; ordinary drills have to almost melt their way through, to their detriment, similar to drilling stainless. Most of the original holes look like they've been punched.

The washer problem has me partially stumped. The bolts shouldn't be so tight as to crush the washer, or the mechanism would be hard to move. It's probably better to place the load on the wheels only for moving, and to lower the frame whenever it's stationary. I don't have reference material close at hand, but I don't think HDPE is a whole lot harder than PTFE; any plastic will creep under constant load, especially under the prying induced by the wheel supports.

Joe

[BobL]

There's something very tough about bed angle iron. Probably a combination of steel alloy and the cold-rolling process. The only way I've been able to drill it is with cobalt drills; ordinary drills have to almost melt their way through, to their detriment, similar to drilling stainless. Most of the original holes look like they've been punched.


Then we are really talking different steels. This steel comes from an old double bed frame I found by the side of the road. As I couldn't fit it into my van I had to cut the frame in 4 places and all I had was a hacksaw with a well used blade - I doubt it would scratch the sort of steel you are referring to. I have also drilled it relatively easily with regular HSS bits.

[joe greiner]

Then we are really talking different steels. This steel comes from an old double bed frame I found by the side of the road. As I couldn't fit it into my van I had to cut the frame in 4 places and all I had was a hacksaw with a well used blade - I doubt it would scratch the sort of steel you are referring to. I have also drilled it relatively easily with regular HSS bits.

Yours might be intermediate between hot-rolled and our stuff. I've cut ours with a hacksaw, >= purgatory. I now generally use a cutoff wheel in a right-angle grinder. I mark the line with masking tape and a witness mark or more tape on the good side for visibility (and to remember which side is the waste). With some practise, I can cut straighter and more accurately than with a hacksaw. This works particularly well for bevel or sloping cuts.

Joe

[BobL]

Yours might be intermediate between hot-rolled and our stuff. I've cut ours with a hacksaw, >= purgatory. I now generally use a cutoff wheel in a right-angle grinder. I mark the line with masking tape and a witness mark or more tape on the good side for visibility (and to remember which side is the waste). With some practise, I can cut straighter and more accurately than with a hacksaw. This works particularly well for bevel or sloping cuts.

I have a 30 year old 8" table saw that I run thin kerf metal cut off wheel on. Its a bit slower than an angle grinder but its much quieter, cooler (it has water cooling as well) and I can keep my hands well back if I want to although I feel I can get my hands much closer to the blade than I ever would on an angle grinder. I can rip, mitre etc with the fence. It's one of my most used tools in my shed.

[jerryc]

Bob,
Particularly like the parallagram system for raising the frame. Whole unit is extremely workmanlike and should give others an idea of what can be done.

Jerry

[BobL]

Bob,
Particularly like the parallagram system for raising the frame. Whole unit is extremely workmanlike and should give others an idea of what can be done.

Jerry

The parallelogram idea I got from TTIT's mobile base. His raises the machine in one go and to do that he links both parallelograms and then place a turning mechanism in the middle. I did think about doing this but it would get in the way of the door on one side or the motor on the other so I went for a simple two lift system.

[Bob38S]

Great design - I like the simplicity of it but realise that as with most things simplicity is hard work - you have done it very well - an idea I will file away for my own use - many thanks for the sharing.

[Carry Pine]

Love the design, Bob. And a lot cheaper than retail.

CP

[Caliban]

And i WAS SO PROUD OF THE modified Soundman's heavy mobile base http://www.woodworkforums.ubeaut.com.au/showthread.php?t=15179&highlight=machine+base
that I used. Rated to 1250lbs. Cost me $75 as opposed to $125 or thereabouts for one from carbatec. Like all great ideas they arrive just after the horse has bolted (to mix a few metaphors.
This is my longwinded way of saying well done.