Crazy (Christmas) Project - Belt Sander

[wobblycogs]

I don't want to waste anyones time so I'll state up front this project is probably crazy but I fancy giving it a go and if nothing else I'm sure it'll provide some amusement.

A while back, like many people here, I watched / read about this project to make a wooden bandsaw http://woodgears.ca/bandsaw/build.html and ever since seeing it I've fancied making one of my own. I could probably afford to buy a bandsaw but I'm fascinated by the idea of making my own machines if I can.

Anyway, I'm still comparatively new to woodwork so I've been trying to think of something that I could make that would use similar principals but be less likely to take my head off if it went wrong. The idea I've come up with is to make a belt sander a bit like this http://www.axminster.co.uk/axminster-axminster-awebds46-mkii-belt-and-disc-sander-prod725061/. This idea was finally cemented when I visited our local B&Q the other day and found a load of belts for £1.

So, my first question: do you think, broadly speaking, it's possible? Assuming it is what do you this tricky bits will be?

I plan on doing a full sketch-up plan but there are some bits that I currently know nothing about. One such area where I lack knowledge is with the axles, do I need bearings or would a friction bearing be sufficient? Due to how long the axles are likely to be rotating on a good sanding session I'm guessing bearings are a necessity but what type and where from? I'm also clue less when it comes to power transfer. I'm guessing a belt drive is the best option? I've Bobs workshop motor document a while back, think I'll go and have another read.

Ok, I've waffled on for long enough. I've got a load of time off over Christmas and my plan is to get this project completed by New Year if possible. I will, of course, do a WIP thread for everyone to point and laugh at

Thanks for any help.

P.S. Hopefully by posting my intention here it will also shame me into actually making something...

 

[Dibs-h]

Ok, I've waffled on for long enough. I've got a load of time off over Christmas

Don't mix it with the vino!! :wink: :lol:

 

[Titus A Duxass]

I have a Shop Notes article describing how to build a Belt Sander (also one for a disc sander and one for a mini lathe).

They are fairly straightforward but need a reasonable level of skill and access to some engineering parts (bearings & axle).

I going for a disc sander as my first project as it is a simpler build.

I'll get you some details of the bearings and axles if you wish.

I won't be doing a Sketch-Up of the project as Sketch-Up doesn't play with Linux.

 

[monkeybiter]

You will definitely need bearings, ball will be fine. I think the 'table' under the belt will need to be a polished metal plate, wood would heat and burn from friction.
Sounds like a fun project

 

[wobblycogs]

Thanks guys. I started doing some proper research last night and came to the conclusion that four 20mm pillow bearings with the axles sticking out to one side for the belt is the way forward (if the makes sense). I'm interested to see what your plans recommend though Titus both in terms of design and bearings.

I also had a look for motors on ebay. I had assumed that the motor would be so expensive it would be cheaper to buy a sander but I was pleasantly surprised at how cheap a second hand motor is. I was thinking of going for about 500W.

From an engineering point of view the thing giving me most concern is tracking and tensioning. From what I can see looking at plans for real belt sanders they don't have crowned wheels so the belt must stay on purely because of the tracking (perhaps the crowning is very slight and I can't see it). I think technically this will be the most difficult part of the project.

Thanks for the advise on the table. I couldn't decide whether to try wood or go straight to metal so I think I'll just go metal on that part.

 

[Titus A Duxass]

I have seen some plans where the drive is through bicycle sprockets and chain.
The plans that I have use 19mm BB ply all round, no metal work other than the axles.

 

[CroppyBoy1798]

Thanks guys. I started doing some proper research last night and came to the conclusion that four 20mm pillow bearings with the axles sticking out to one side for the belt is the way forward (if the makes sense). I'm interested to see what your plans recommend though Titus both in terms of design and bearings.

I also had a look for motors on ebay. I had assumed that the motor would be so expensive it would be cheaper to buy a sander but I was pleasantly surprised at how cheap a second hand motor is. I was thinking of going for about 500W.

From an engineering point of view the thing giving me most concern is tracking and tensioning. From what I can see looking at plans for real belt sanders they don't have crowned wheels so the belt must stay on purely because of the tracking (perhaps the crowning is very slight and I can't see it). I think technically this will be the most difficult part of the project.

Thanks for the advise on the table. I couldn't decide whether to try wood or go straight to metal so I think I'll just go metal on that part.

I'm hoping to make a drum sander soon, theres a thread in this form about it somewhere from a few months back. Anyway, I have a lenght of 20mm axle and two 20mm pillow block, the only problem being that I cant seem to find a 4" pulley with a 20mm bore, I think 20mm was hard to come by in general, they were all 19, 21, etc. Just something to keep in mind as you'll be using pulley and belt. Gonna hve to have the end of the shaft turned down to 19mm.

 

[wobblycogs]

Many thanks for that info CB. As per the wooden bandsaw I was planning on making the larger pulley out of wood so I should only need to find a metal pulley for the motor end assuming the motor doesn't come with one. I haven't yet come up with a way to fix the wooden pulley to the metal shaft though...

I have a variable speed woodworking lathe and I think if I drop the speed right down I could probably just about turn aluminium so if push comes to shove I could probably reduce the size of the shaft at one end.

Good luck with the drum sander. I found the thread for that last night while looking to see if anyone else had made a belt sander. Looks like a complex build.

 

[SammyQ]

Wobbley? British Blades Forum; search "Aly" and his range of grinders. They're simple, tested and easy to emulate. PM me if you can't find him; I've got a set of downloaded pikkies and details somewhere in the 'tuit' files...

Sam

 

[wobblycogs]

Wow, those grinders Aly makes are top notch pieces of kit. I don't think I'll be able to emulate that build quality for this project as I have no metal working kit. While I would love to get a welder I think that's a step too far for now. Some good ideas there though, cheers.

 

[SammyQ]

Cheers. Just remember, you don't need a welder to build a look-a-like. Tapped holes and nuts/bolts will suffice, given you are not putting massive tension on the belt. Also, look at the VERTICAL sanders, not the big wheel HORIZONTAL ones. The square bearing plates are cheap as chips on the web and the basic frame is quite simple. (Ses he, who knows all this and hasn't bothered his rear end doing anything about it...).

Sam

 

[CroppyBoy1798]

Wow, those grinders Aly makes are top notch pieces of kit. I don't think I'll be able to emulate that build quality for this project as I have no metal working kit. While I would love to get a welder I think that's a step too far for now. Some good ideas there though, cheers.

While most of the bits and bob I've got out of Aldi over the years has been rubbish, one of the best buys was the arc welders that they sell from time to time. Well worth picking up if you see them come up again. The rods they sell are rubbish, but the welder is fine and has done a heck of a lot of work for me, from making gate/door frames to heavy shelving and brackets.

 

[kirkpoore1]

From an engineering point of view the thing giving me most concern is tracking and tensioning. From what I can see looking at plans for real belt sanders they don't have crowned wheels so the belt must stay on purely because of the tracking (perhaps the crowning is very slight and I can't see it). I think technically this will be the most difficult part of the project.

The drums on belt sanders are crowned. It is slight, so you have to put a straight edge on one to see the crown, but it's definitely there. You will still need to adjust the tracking, however. I can try to dig up the pictures of my Powermatic belt/disk sander restoration to give you an idea of the mechanism, if you want.

For the platen, I would have originally said metal, but now I think you can get aways with hard wood or even thick MDF. Whatever you use, get some graphite fabric to glue down on it. It cuts down on the friction and when it shows real signs of wear, you can take it off and replace it. That way your platen will not get worn out.

Kirk

 

[wobblycogs]

Pictures of the tracking and tensioning system would be interesting but don't worry if you can't find them straight away. I've grabbed a copy of one of the Jet belt sanders manuals which has a pretty good diagram. My plan currently is to mount the free running wheel in such a way that it can be tensioned and adjusted by turning two or three bolts.

Never heard of carbon cloth before, I'll have a look for some tonight. Starting to put together a shopping list now. Found some cheap bearings earlier - they'll probably break down in no time but I think I'm going to have to treat this project as a learning exercise...

 

[kirkpoore1]

Never heard of carbon cloth before, I'll have a look for some tonight. Starting to put together a shopping list now. Found some cheap bearings earlier - they'll probably break down in no time but I think I'm going to have to treat this project as a learning exercise...

This is the sort of stuff you're looking for:
http://www.abrasivesupply.com/Stroke_Sander_Graphite_Cloth_s/288.htm

Note that the price is by the yard, but of course that will give you enough for several sanders.

Kirk

 

[xy mosian]

.... I'll state up front this project is probably crazy ....

Yeah you're probably right . So what, you'll learn a **** of a lot and enjoy yourself, well some of the time anyway. All power to your elbow.

Some years ago I designed and built a powered fretsaw/ scrollsaw. I'm now on version 3 or 4. Now it doesn't get used a lot, which is why I built rather than bought. Yesterday, in use, the top blade holder came loose on the blade, first time, and as there was no method to constrain it, it shot up to the ceiling in the loft bounced off the kingspan and departed to another galaxy. So do I spend twenty years looking for it? It's about 16mm diameter and 18mm long. Or do I make another, if so now where are all my taps etc. Still, Hey Ho.

Belt tensioning and tracking. Off the top of my head how about tensioning each bearing of the trailing roller separately? That way you can use the same arrangement for the tracking.

HTH
xy

 

[wobblycogs]

Right then, some frantic research later I've started the design but I seem to have run into a dead end so I'm hoping to get some suggestions . Note that it's far from complete (loads of supports etc missing) but I wanted to get the difficult bit, tensioning and tracking, nailed first. So, here's what I've got so far:

Front

Back

Everything was going fine until I went to insert the platen and realized that I didn't have space for it hence the over lap on the right hand red bolt. The carriage that carries the idler wheel is held down by the blue bolt which runs in a slot on the base plate, a wing nut on the under side locks the idler carriage in place once it's running true. The two red bolts are used to adjust the tension and tracking while the blue is slightly loose. Do you think this will work?

I'm a bit concerned that if I move the right hand red bolt over it will have too course an action to set the tracking correctly. Two bolts for tracking and tensioning also feels like it will be overly complicated to adjust. Presumably I could replace one of the red bolts (the right hand one I think) with a spring but that feels like I'd be complicating the design even further.

On to motors now. I've never bought a motor before but I've finished Bobs guide and a few other resources and I'm thinking a .55kW 4 pole foot mounted singe phase motor is the way to go. I currently have 10cm belt wheels (are these called pulleys too?) on the design which my calculations indicate will give about 450m/min at 1400 rpm. Sound about right? Can anyone recommend a good motor that fits this spec or would I just be better going for a cheap one from eBay?

And there was me thinking this was going to be an easy first project...

 

[xy mosian]

How about moving the right hand, fouling, bolt to be in line with your clamping nut and bolt. This for the tension. Then make the left hand bolt captive in the slide so that its movement 'rocks' against the clamping bolt for the tracking?
HTH
xy

 

[wobblycogs]

Thanks for the idea XY but I decided to bite the bullet and go with a sprung design as seen below. I'm pretty happy with this design now. It looks simple enough to build and should be adjustable enough - I realized that commercial designs have the tracking bolt right next to the wheel so mine should probably be more accurate.

There's a problem though, I've priced up the parts and it's only worth building if I'm doing it for fun / learning. Once I've added in all the bearings, pulleys, bushes, motor, nvr switch and countless other little bits and bobs the price comes to about £200 which is the same as a really nice belt sander from Axminster. The only way I can really justify the build is if I can buy parts that will be useful on other projects so...

Bearing in mind that I want to build a bandsaw (that cuts wood and metal) and a CNC machine at some point I'm going to need an inverter. Searching on ebay I found item number 230493817712 (just stick the item number in the search field), a 2.2kW inverter from Hong Kong - Part No Huanyang HY02D223B. Reading 9fingers induction motor document this is, I believe, what I need to run a three phase motor with variable speed. The added advantage of an inverter, of course, is that three phase motors seem to be a lot cheaper and more reliable.

So my (dumb) questions are:

0) Does this inverter convert single phase 230V to three phase (230V)? Pretty sure that's what it does but I just want to check
1) This inverter is 2.2kW (output presumably) can I power a much smaller motor with it? I would like a 0.55kW motor on the belt sander but (probably) a 2.2kW motor on the bandsaw and about 1.5kW on the CNC machine.
2) Can I fit a standard three phase industrial socket to the output so that I can easily switch the inverter from one machine to another?
3) How easy do you think it will be to switch from one machine to another, will it require a lot of re-programming? I read a thread on a CNC forum where people were talking about manual programming that was needed to run the router motor - these are very high RPM motors though so perhaps they are outside the standard settings.

I've got a manual for this range of inverters which I can supply if it helps. Many thanks again folks.

 

[9fingers]

So my (dumb) questions are:

0) Does this inverter convert single phase 230V to three phase (230V)? Pretty sure that's what it does but I just want to check
1) This inverter is 2.2kW (output presumably) can I power a much smaller motor with it? I would like a 0.55kW motor on the belt sander but (probably) a 2.2kW motor on the bandsaw and about 1.5kW on the CNC machine.
2) Can I fit a standard three phase industrial socket to the output so that I can easily switch the inverter from one machine to another?
3) How easy do you think it will be to switch from one machine to another, will it require a lot of re-programming? I read a thread on a CNC forum where people were talking about manual programming that was needed to run the router motor - these are very high RPM motors though so perhaps they are outside the standard settings.

I saw the beginning of this thread and considered the OP to even more eccentric than me and did not read on. In response to a PM I now see that the op is still digging. I have to admire the enthusiasm but still doubt the sanity :lol:

My thoughts on the questions:-

0) Yes - therefore the motors you buy MUST be dual voltage 230/400 types with 6 terminals and need to be wired in delta (230 volt) mode

1) The inverter should be able to be programmed to say 125% of the current ratings on the motor plate. This will need to be changed every time you swap motors. Motor inverters will measure the stator resistance each time it is switched on.

2) Using a plug and socket connection is potentially risky as it could be possible to damage the inverter if the motor is unplugged without the inverter being switched off AND the motor being allowed to come to a halt. Also it would be easy by mistake to connect a low powered motor when the inverter remains programmed to a higher power setting. This means the motor is not adequately protected and could be damaged if there was a mechanical overload.

3) I think this is covered mainly above. In addition programming usually needs many key pushes and entering of motor specific data.

Yes it is possible to just use a single inverter but will need self discipline to avoid problems.

Although more expensive I would always advocate separate inverters matched, programmed and hardwired to each motor.

I do have one installation with a single inverter switched between two motors but these are equal power motors and the changeover switching can only be achieved when the power is switched off. It is almost impossible to get this wrong.


hth

Bob