Saturday, 29 June 2019

Pillar Drill

I've had a small pillar drill for about a year, and pretty cr@p it is too - but it was very cheap and it's a whole lot better than what I had before, which was a hand-held power drill in one of those bench stands.

This one works well enough, it has the usual stack of five pulleys and belt drive, belt tensioner, convenient power switch etc and you can set the table at an angle. But it is very flexible - the base and the table are pressed steel and the pillar is very thin - the whole thing will bend when you put any feed on.

The spindle is mounted in sealed bearings but once the quill descends it has quite a lot of play.

Here's the depth gauge and guard - this is hard plastic and broke almost the first time I used it. The depth gauge requires you to fiddle with those two nuts:

I decided to make a new mounting for the guard and depth gauge, but mostly because I want to do some boring in a big-end type arrangement (like a locomotive eccentric strap). The new mounting is made from two lengths of 10 x 30 mm aluminium bar, screwed together with two M4 screws and shaped to match the old one. Here, I am aligning the components with the lathe centre prior to drilling and boring a 40 mm hole to suit the journal on the pillar drill. The two halves of the clamp are spaced 1 mm apart, so they clamp securely to the drill:

Here it is in place, along with the broken bits of the original:

Thursday, 27 June 2019

Mini Lathe Updates

Readers might be interested to know that the mini-lathe page:

has been updated this week, with a few new bits:
  • a 3D printed apron gear cover
  • a modification to the tailstock die holder
Thanks for reading, and I hope you find it useful.

Dry Build - Siting the Oil Filter

These plain journal engines run close tolerances and need a decent oil filter. Modern oils keep the dirt in suspension and if there is no filter, the oil becomes contaminated very quickly.

The SQ4 has a Norton commando oil filter, like this one, fitted under the gearbox where:
  1. you can't see it
  2. you can get to it easily
  3. it doesn't ground on kerbs
We'll need a similar site for the filter on the FH.

There's a lot of space behind the engine, between the engine/gearbox plates - but not for this filter, which is marginally too big for this location.

Beneath the swinging arm and in front of the mudguard is a likely location used by many FH owners. I'll need to find a location where I can easily mount the filter and where the oil lines will be able to get to and from it without kinks - and it must also fulfil the other criteria I listed above.

This is probably no good - there is nowhere to mount to and the oil line routing could be a bit tortuous:

This is an example of a mounting used in that area:

This one is on AOMCC forum member Steve Carter's Ariel Cyclone.

And another - this is AOMCC Kieth Mettam's filter:

Another one from Steve Carter, this well used Huntmaster carries a Morgo filter - these are smaller than the Commando filters and easy to place - but they are quite expensive and it makes sense to me to use a unit I already have elements for, commonality of spares and all that:

This is my choice. I'm using a mock-up bracket, made from a bit of 20 swg sheet, welded to an old footrest bar sleeve nut and placed in the sidecar lug beneath the swinging arm:

It's too far back, and the oil lines foul the gearbox casing:

Time to cut it up and shift it around:

To become this ugly but effective thing, including a bit of butt welding practice:

Also pictured is the beginning of a special bolt that will locate the filter bracket in the sidecar mount.

This is better. It's further inboard to allow the oil lines to pass the gearbox outer casing, and further forward to guarantee the filter clears the mudguard and rear wheel:

The next step is to replace the bracket with one made from 3-4 mm sheet, and finish the special bolt that holds it in place. I'll use the same old sleeve nut, but I will probably machine a journal in it to fit in the hole properly.

Here's the finished bolt:

It's in the wrong side, but I'm just testing for fit. I wanted to make it look like the swinging arm nuts.

I'm tubing up using a mixture of Huntmaster and BSA A10 oil lines. The long A10 lines stretch from the engine right around under the gearbox to the oil filter:

I've spent a long time faffing around with these connections, even considering moving the filter altogether. In the end, after a session mulling it over one night in the workshop with my son, we concluded we could get it all in there if we modified the fittings:

I've shortened the unions in the lathe and gained about 5/16" which is enough to give the gearbox it's full range of adjustment. This allows the gearbox to move and the oil lines to follow the routes I'd laid out. A minor problem is that the return to the tank is touch on the long side and the route has to cover a 120° bend on top of the gearbox, which is a bit unsightly.

Tuesday, 18 June 2019

Brown Trouser Moment

I've had a few nervous moments in SQ4 ownership, shared by several co-owners if the stories on the AOMCC forum are anything to go by. Not least of these are the few occasions where oil pressure has suddenly and completely disappeared, accompanied by a more or less continuous return flow to the oil tank.

Fortunately, the first time this happened was on start up - or at least, that's when I noticed it. Investigation was interesting - removing the front main bearing cover to look at the oil pressure relief valve revealed that the spring had become caught in the split pin, and the split pin was now part way down the spring, preventing the spring exerting any pressure on the ball and allowing to come off it's seat.

I put it back, noting that the direction the spring was wound in would always allow that to happen and wondered if original springs are would in the opposite direction.

It happened twice more - once outside a smoke house along the coast. Knowing what it was, it was any easy fix if a little nerve racking - everything was rather hot, and I was nervous of losing small parts in the dirt. However, I was buoyed up by another motorcyclist stopping to see if I was OK.

The next morning, the same thing happened - very low, but not zero, oil pressure on start up. It had happened again.

I needed to do something. The spring lives in a bore which is a little over 6 mm - I can't measure it, but a 6 mm drill is a rattle fit while a 1/4" drill won't go in. The spring is about 5.5 mm OD and 4.5 mm ID:

I planned to make a brass cap to house the end of the spring, preventing the split pin from coming into contact with the coils.

However, I came across this cable ferrule which fitted beautifully. all I have done with it is to drill it out to 3.5 and use a needle file to open it a little more - all the relieved oil has to pass through this hole:

This works perfectly, and makes it much easier to get the split pin in.