Hemingway Knurling Tool

After the success with boring the 5/8” hole between the 2 arms, today I decided to use a sacrificial piece of steel to bore the 5/8” hole on the top arm. I made up a 5/8” brass plug to gauge size. I really need to get a set of bore gauges.

I also got the bottom arm drilled and reamed out 1/4”

After using the bore gauge, i used part of it to make a centre for my fixture plate, just a plain centre, drilled and reamed 6mm for use on the next operation, rounding off the ends of the arms.

Cheers

Mark

I made a start on the ends tonight, changed the vice out for the rotary table... again... and got set up. I’m going to take it down to .25mm with the rougher then take the last bit with an end mill and see how that works out.

Cheers

Mark

Edited By Mark Elen 1 on 10/12/2018 21:56:41

Tonight I’ve got all of the radiused ends done on both arms.

Here is my method of centering parts. I turned up a central spigot, as the locating holes in the arms were 6mm, it’s really just a 20mm extra thick washer reamed 6mm in the centre. I also turned up a 6mm silver steel rod with a point.

With the part free to move and the pointer chucked up in a collet, the pointer was fed through and located in the spigot, then the arm was clamped down and a 6mm screw is fed through the centre of the table and threads into the MT2 stub arbour that the sub-plate locates on.

It all worked a treat and I’m happy with the results.

Cheers

Mark

Nice work mate.

Thanks Ian,

Tonight I made a start on the slots in the arms where the wheels fit. The slot needs to be .188” or 4.775mm in my money. So I thought I would use a 4mm end mill and offset it .38 either side once I had got to depth. It would have worked, except the slot needs to be 15 odd mm deep and my 4mm end mill only has 11mm usable length in the flutes before it flares up to the 6mm shank.

I used my cutter to make a start and ordered a ‘long series’ to take the final 4mm or so out.

As it was all set up, I left the mill and started on the bottom pivot on the lathe. I did have a go at the silver steel with a carbide insert, but I think I was taking it too easy and the silver steel seemed to be work hardening and at one point the cutter wouldn’t cut. I changed over to hss and made this:

Both ends need facing off to length, but I’m pretty happy, the lathe is cutting it nicely with a bit of cutting fluid and both ends mic up at 6.35mm and are a nice sliding fit in a 1/4” reamed hole. I took them down to 6.4 and then finished them off with an emery board.

Cheers

Mark

Edited By Mark Elen 1 on 12/12/2018 22:28:14

I made my slots 1/4" wide to permit a far wider, and more importantly, cheaper choice of knurls. 1/4" wide is a very common size, ie 0.250 x 0.250 x 0.625 or 3/4" knurls.

I was a bit wary with the thickness either side of the slot, but the tool has been used in anger now for several jobs with zero problems.

Hi Thaiguzzy,

Thanks for your comments. I have considered opening out the slots for the knurls and it makes a lot of sense. As I bought both the fine straight and fine diamond set with the kit, it would mean me making up washers to space these correctly.

I have decided to build to plan, but keeping in mind that if I need to, in future, I can open up the slots to take the wider knurls.

I have got a bit more done this week, and I’m going to take lfoggy’s advice and harden the pins that the knurls run on.

Apart from some cosmetic work to tidy them up, all holes are now reamed to dimensions and the arms are finished.

Cheers

Mark

Those pin keepers were about the most difficult thing on the job......

Bloody tiny and too tiny for what i'm used to.

I dunno how model engineers do it with M2 and 8BA screws and tweezers..... Drive me potty with an eye glass and my podgy fingers...

Kudos.

Yes, I know what you mean. They weren’t too bad, but I much prefer bigger chunks and big cutters.

I managed to swing a day off work today so between deliveries of Christmas presents and having a smart meter fitted, I managed an hour or two on the knurling tool.

I made a start on the side plates, squaring one edge up, using this and an edge finder to set up the DRO, then spotting all of the holes, followed by the necessary drill/ream/tap/countersink.

It all worked out pretty well, it’s not far off as it all fits together. Now I just need to remember to bring the other edge square and to final dimension (both plates were supplied ~5 mm over length)

I have decided that it makes more sense to do all of the milling operations that need doing with the vice, and then swap over to the rotary table and mill all of the curves.

Cheers

Mark

The workshop has taken a back seat this week due to a family bereavement. I did manage to get an hour or so today, I have found being busy has taken my mind off things somewhat.

Today’s jobs were to mill out the slots and drill the ends 6 mm for location on the rotary table on the adjuster side plates, I will use the 6mm holes and my 6mm silver steel to relocate these in the vice to finish off the holes to correct dimensions once the ends have been rounded off.

I also made a start on roughing out the side plates, in the photo below, all dimensions are .25mm oversize, I’ll bring them into final dimension with a standard cutter.

Cheers

Mark

I managed to get a little more done this afternoon. Changed out the vice for the rotary table and sub plate and got the adjuster arms milled round and the spacer done as well.

Just the 2 main side plates to round all of the corners off and I can get the vice back on and take all of the holes to final dimensions.

Cheers

Mark

Got a bit more done today, all of the rotary table work is now complete.

I set set up a couple of ‘fences’ so that the side plates could be located on each corner and checked location using the end mill before changing for the rougher and taking most of the meat before changing back to take the last .25mm.

Lots of tool changes and set up work, I couldn’t resist putting all of the bits together to see how it looked.

Cheers

Mark

During the adverts of the Star Wars film tonight, I ran up the 3/8” BSF adjuster screw. Had to fit the 127 tooth change gear, I’m happy with how it turned out. First imperial thread cut and a die runs down it nicely.

Please excuse the state of the lathe. It needs a clean.

Cheers

Mark

Nearly finished! Congrats.

I find most of the Hemingway Kits workshop tooling projects interesting to make and useful additions to the workshop.

Hi Thaiguzzy,

It’s certainly coming along. One of the problems with buying the mill first, is that I’m much more confident on it than I am on the lathe. It’s probably why I have done most of the milling jobs first. I’m going to have to bite the bullet now and get on with the round stuff.

All the best for the new year👍

Cheers

Mark

I'm the other way round.

The round stuff has always been far easier to machine (accurately) than the flat stuff.

All the best.

TG

Thanks TG,

I got a bit more done this morning, starting with the adjuster nut. All went well, but what a nightmare to tap. I used a 3/8 BSF HSS tap, brass is not like tapping steel. I took it steady and it worked out ok.

Cheers

Mark

Excellent work Mark👏

Can recomment their kits.

Geoff - Need to decide Workshop or Austin Seven?

Thanks Geoff,

Are they your spare knurls bolted to the sides near the adjusting screw?

First day back at work today, and thankfully, I got done early, so on with the project. I managed to get the trunnion milled into shape, it nearly broke my heart taking a stone to the new 3/8” drill to break the sharp cutting edges to drill brass, but as I’m all metric, I figured ‘it’s only an imperial drill, it’s not going to get much use’😂

Tapping the small M4s was a joy compared with the 3/8 BSF

It all works nicely, and I can run the adjuster by hand to both extents by just holding the threaded part. I’m happy with that as my first real fitting project.

Cheers

Mark

Edit: doh. Read the words Mark, don’t just look at the pictures...

Edited By Mark Elen 1 on 02/01/2019 22:30:21

Nice job Mark! That will be handy in future!