Pillar Drill and hole saw

[jg]

As some of you may remember, i've got one of those homebase "powerbase Xcell" pillar drills. I was trying to cut out a 50mm circle in some 6mm MDF sheet a couple of days ago, while drilling, the saw snagged and stopped turning, I quickly hit the power button and stopped the drill. I tried again and was VERY careful to cut as slow as possible.

When the drill got stuck I think the motor was still turning, so the belt was probably slipping. The drill is set to the middle of 5 speeds, would it help if I adjusted the speed to a slower/faster speed? Should I have used some kind of lubricant while drilling?

If I need to adjust the speed, any ideas on how to do this? Do I just pull off the belt and put it on the correct pulley?(I didn't get any instructions with the drill as it's an ex-display model).

Thanks for any help.

[Norman Billingham]

You don't say what tool you are using to make the hole but I infer that its one of those hole saws with a drill in the middle and a tubular saw blade?

These are really designed to cut only very thin material and usually have teeth designed fro metal. As with any cutter, the sawdust you make occupies a lot more space than the original wood. For a hole saw, the teeth are all buried in the wood and the only place for the cut material to go is the gaps between the teeth. Once these are full (about 1 revolution if you are pressing hard), everything starts to jam up becasue you force sawdust sideways.

Use a low rotation speed to avoid jamming and burning, and go with a "pecking" action, bringing the blade out very often to allow the sawdust to clear. Don't expect a great finish to the walls of the hole. If its the hole you want rather than the disc that comes out, then a template guided router will do a much better job.

I don't know your drill but usually there is a means of sliding the motor forward a little to release the belt tension, so that you can move the belt to a different pair of pulleys.

For this job keep the belt not too tight - better to let the belt slip than to stall the motor.

[John Schmitt]

More likely either the chuck was slipping or the shaft of the holesaw was slipping relative to the body. V-belts, when they slip, tend to advise you of this fact by the odour of burning rubber. As another poster has pointed out these cutters are prone to "choking" and the sawdust/swarf needs to be cleared regularly.

Normally, (with the power off, naturally) you hand rotate the larger pulley the belt is riding on and "derail" it towards a smaller pulley. This allows you to select your desired drive ratio. As they say, assembly is the reverse of disassembly. Try to keep your fingers from being trapped. Perhaps an obvious point, but I am reliably informed that it hurts.

John Schmitt

[Ian White]

Which is short for "(with the power switched off in TWO separate places before you put your fingers in machinery)".

[John Schmitt]

Absolutely. Ideally keep the fuse (or MCB) in your pocket. In the 1980s I read about a man servicing a machine for shredding tyres. He climbed in without isolating the thing and exited in small pieces. Someone was kind enough to switch the machine on. Apologies to those who have just taken lunch.

John Schmitt

[Tony Williams]

In article , jg wrote: [snip]

Use the holesaw to lightly mark out the circle. Then drill a series of holes on the inside of the circle, nearly touching the circle and right through. The holes are outlets for the swarf to fall through. Set the pillar drill to the lowest speed, belt only lightly tightened. Now slowly go through with the holesaw. Woodpecker it... light cut, lift, light cut, lift, and so on.

[John Rumm]

I can't speak for your particular drill, but many seem to work in the same way. If you open the cover where the pulleys / belts are housed, there is often a diagram or table of the different speeds and the required belt positions to achieve them (failing that you can usually work out the relative speeds simply by looking at the sizes of the pulleys in use). Typically you undo a wing nut or two to allow the motor to slide closer to the drill body - this slackens the belts, which you can then derail and move about with a bit of manual rotation of the pulleys. Finally slide the motor away from the drill body and do up its retaining nut(s) to re-tension the belts.

[Chris Hodges]

This is of the reasons the pillar drill at work has a lockout. The other main one is to stop idiots using it.

[PC Paul]

Not as bad as the engineers servicing a conveyor fed bread oven. It came back on (timeswitch) and apparently it wasn't possible to get into them before they were very badly off. Supposedly all the people who knew how it worked well enough were inside it...

They practically tore the machine apart but couldn't get in.

[Owain]

[Dave]

On s similar theme.

I work at a school and occasionally have people working on the electric's. What is the best way to prevent anyone from turning back on a circuit breaker? The type I am talking about is like a switch on a panel and they have the current rating marked on them. I have discussed this with various electricians and no one has come up with a system that can be made fool proof. Note, the circuit breaker panels are in two rooms that the staff have easy access to, so I can't lock them out. Is there a device that can be attached to the breaker that will prevent any switch on?

Dave

[Ian Stirling]

Can you padlock the enclosure of the panel? If none, can you install such an enclosure?

You want an enclosure with multiple padlocks that go through the same bit, so if two people are working, you lock each lock it with your lock, and take your key with you.

A more trusting measure would be to tape a cardboard box over the panel, with "If you move this, you may kill me, with a picture of yourself". Not a good idea if not liked :)

[PC Paul]

Some main switches (but not really MCBs) have holes which line up when switched off so you can put a small padlock through it.

Otherwise put a *big* notice taped over the whole thing. If anybody ignores

*that* do them for atempted (or actual!) murder...

[Dave Plowman (News)]

I'd set it to the slowest setting and leave it there - since these low price pillar drills are rather lacking in power. But anyway, there's no need for a high speed with anything, IMHO.

It's likely the chuck slipped on its taper.

Really, the speed change and possible re-tensioning of the belt should be well and truly obvious when you do it.

[John Schmitt]

do a six point lockout, i.e. it will accomodate six padlocks while securing a lockable unit. Until all six keyholders have removed their padlocks, the unit cannot be opened. These can be daisy-chained, of course, so the number of workers is effectively unlimited.

John Schmitt

[Ian Stirling]

Seton, just the people I was thinking of. One of the cataloges that you leaf through thinking how useful it would be if you had any use for the stuff in it...

[Chris Hodges]

I'm sure I've seen them in RS as well. I would recommend RS's website,

but it's a horrible javascript thing that makes it hard to open lots of similar things in different tabs (or windows if you're stuck on ie) unlike their old site which was reasonably easy to use.

[Owain]

Taped notice not good enough. Any isolator not under the control of someone working on the wiring *must* be locked off - that includes bathroom fan isolators in houses, the MK ones at least come with the lock-off bracket.

If the main switch (MCBs are usually single-pole, so don't provide isolation) can't be locked off, then an electrician's mate should be paid to stand in front of the switch. (The problem then arises of what to do if the fire alarm goes off ...)

It should be borne in mind that someone who permits or authorises an unsafe system of work may be personally liable ...

Owain