Lathe - tool storage

 In a bid to clear up the lathe area a bit, I bought a magnetic knife rack from Amazon. The magnets seem a bit weak but I suppose you don’t want to be struggling to pull a 9” carving knife off the rack and risk it flying across the kitchen.

As you see, it keeps the tool holders neat, tidy and accessible:

Lathe - cheap collet chuck

 I use my ER25 collet chuck quite regularly, generally because it's more accurate than the three jaw chuck. It's a morse taper fit in the lathe spindle and consequently has a very short capacity - you can't fit more than about 50 mm into the collet holder before the work bottoms out.

Therefore, I thought I'd buy a flange mounted collet holder which would allow me to pass the workpiece right into the lathe spindle. You can buy a lot of stuff online, usually made in China, for little money these days and to be honest that's what's enabled me to develop my machining skills without breaking the bank. However sometimes these things are not quite the quality you would want. 

Here's a little video. Look at the dial test indicator needle waving around all over the place:

The whole collet retaining assembly has a 0.4 - 0.5 mm runout compared to the spindle locating feature on the back. 

To fix this little problem I initially removed the collet nut. The first step was to rebore the 16° cone that receives the collet; that helped a little bit but didn't give me the accuracy that I was looking for. 

The cone in the faceplate is mirrored by another cone in the nut. The collet itself is suspended effectively between these two cones centralising the collet to the lathe, so the concentricity of the nut becomes critical - and was eccentric by something like 0.5 mm. I'd have to recut the thread and hope it would retain enough strength.

I used the Little Machine Shop gear calculator to set up the lathe gear train and set about cutting the thread. The first attempt didn't make enough difference - I still had something like 0.25 mm run-out.

I changed tools and turned the outside diameter such that it was concentric, taking the minimum amount off, and recut the thread again.

By the time I'd finished I had taken 0.5 mm out of the thread diameter, biased to one side as I expected. Another test showed it could be improved a bit more, and I removed another 0.05 mm to get this:

No runout at all. Better than I dared hope for!

FH - indicators

 I've decided, mainly at the behest my son that the Huntmaster is going to have indicators. I've bought some small circular indicators from eBay which will look the part but I'll need to make some stems to put them in the right place and to fit them to the bike. I made this drawing to show what I wanted to machine and I'll do that on the mini-lathe.

We'll start by cutting four blanks from 0.515" hex bar stock. This is EN1A.

With the first end faced and centred it's time to put some marking blue on the far end in order to turn all the blanks to length. We'll start drilling the 3 millimetre hole for the cable at this point as well. I've got some long series drills just for the purpose.

The next step is to face the ends to length, centre drill and drill 3 mm through the length of the blank. Then we'll turn the M8 thread for the indicator lamp and start reducing the hex to the final diameter for the stem. We'll do this in two halves because we'll want to switch ends in order to turn the 5/16 CEI thread that holds the stem to the bike.

With the outer end of the stem finished on all four examples it's time to look at the inner end. This has a 5/16 CEI thread to bolt into the original fastenings on the Huntmaster. In most cases there is sufficient hexagon left available for us to be able to hold the stems in three jaw chuck. 

First we need to use the height gauge to mark off the length of the 5/16 thread and the height of the nut that we will need to fit the stems to the bike. I painted all the stems with Dykem to facilitate the marking out.

I've got the 5/16 thread now on all the stems, and I've drilled through 3 mm for the wire to pass through from the indicator lamp. 

For the next step I wanted to hold the stems in the collet chuck to avoid damaging the fine 5/16 CEI thread. The next step is to finish the main stem length turn it to size and then to turn a feature in the end to give the stem a little more shape.

There are three examples of the finished article you'll notice the feature that I was talking about and you're probably also noticed that the hex element is not the same length in all of those examples -  we'll have to refine that later.

Here's one of the short stems fitted to the lamp and fitted the front of the bike - it's looking pretty good I think. 

Now, there's a bit of refining to do on the height of those hexagon sections but then we'll assemble these to the lamps, degrease them and paint them.

I'll use a little bit of wood as a jig while I paint them:

Not too shabby.

Charlie's Shed - clutch holding tool

 One of the problems that you can have when you're working on a bike is trying to undo nuts from components that spin around such as the clutch or the engine sprocket. 

Today I'm going to show you how I make a tool out of two clutch plates to hold the clutch in place while we undo the centre nut or conversely do it up again. 

Regular readers will know that I've built several clutches over the last few years and have a number of old clutch plates knocking about. To start with I've taken a friction plate and removed all the old worn cork inserts. Then I've added a plain plate and placed the two over the top of each other in the way they would appear in the clutch using the TIG welder to fasten them together.

Once you've got your two clutch plates together you'll need a handle - there's no point having the clutch basket and centre fixed together if it's still going to spin. In my case the handle is made from a piece of old door threshold - effectively a rough piece of 20 mm by 5 mm flat bar. I've used the TIG to place a fillet weld around the base of the flat bar and attach it to the clutch plate assembly.

I used the TIG torch to heat the handle and form a local bend as an experiment. The problem I have with forming hot bends by my usual approach - a MAPP torch - is that the heated area is so big, the bend is anything but sharp; OK if you want it like that, but this one needs to be in just the right place.

It's worked rather well I think. I'll show you how it works when I put the FH clutch together.

SQ4 - bushing the saddle nose

Updated: First published June 2021

Since I've had it on the road, the Square Four has felt a bit wayward around the rear end. Since I had rebuilt the rear suspension and knew that it had no wear, I suspected the tyre and wheel though they were both new and rebuilt - until I realised the problem was closer to home. Literally much closer, to my backside.

The saddle nose bracket on an Ariel frame is quite small, giving little bearing area. Coupled with a bolt with an over-long thread, used as a bearing surface produces this effect after a few years:

This picture shows the saddle removed, but with the bolt in position. The red circle shows a portion of the thread used as a bearing - a very poor idea:

So, the first job is to make those worn holes round again. The bolt is 5/16" (0.312", or around 8mm), and they are both worn to over 0.350". I used an adjustable reamer on them to remove the ovality.

Ovality in the frame holes is not the only problem - the holes in the saddle frame are also very large. I have another problem in this area in that the fuel tank has very little clearance around the saddle nose bolt and I have solved both these problems in one go. In this picture, the original bolt has had it's head thickness reduced to produce a shoulder which fits in the saddle frame hole with very little clearance, and the full nut used at the other end has been reduced to the thickness of a half nut, again with a shoulder. This enabled the bolt length to be reduced, to get more clearance for the tank, and removed the whole assembly to the right to move the thread out of the bearing area.

Next job was to make two shouldered bushes to fit in the holes:

The bushes pass right through the fixed frame lugs, to provide maximum bearing area; there is a minimal shoulder to allow the bush to be retained in place (or removed).

This repair has removed virtually all the play from the saddle nose bearing.

Three years after I wrote this, I sorted out another problem - that of the bushes coming out of the frame lug and all play returning. I made a spacer on the lathe:

It's just a bit of 1/2" round bar with a clearance hole for the bolt; it's relieved slightly in the middle as the pivot bolt is very close to the frame lug.

Posterior stability has been restored.