Member postings for Roderick Jenkins

"JB weld-original cold weld steel reinforced epoxy" is the one you want. If I don't need the extreme heat resistance and grey colour then the original (blue) Araldite is as strong for domestic purposes. Remember that in all gluing situations, good surface preparation gives the best bond. Our adhesive specialists at work used to glue PTFE components together with Araldite. Mind you, they had to etch the surfaces with Hydrfluoric Acid

Rod

It's been a while. Hoglet and I fell out so I thought it would be better if we spent some time apart. We're communicating again now (all my fault). I had spent some time debating whether to use CNC or manual methods for the con rods. I'd assumed they were much the same so the same CAD drawing would do for both. For some reason I was completely blind to the differences in the plans. Made one con rod and had to rectify some issues with the CNC mill.

The blank was drilled and reamed on the manual mill for the big and little end pins, then profiled on the CNC

Moved to the manual mill to thin the shaft

and bring the end to the right thickness

I was not particularly happy with the way that plans use glacier type bearings so decided on some bearing bronze for the big end. Note the asymmetry in the bulge caused by a backlash issue on the CNC Y axis.

It turn out (obvious really!) that the forked con rod needs relief on one side to allow free movement of the other rod in the narrow V between the cylinders and some more meat at that end to allow for it..

Profiled manually

Little end thinned to 1/4"

After a little bit of titivating with files and scotchbrite

Rod

Cheers Baz.

Roger, here's a few more pics of the DRO. Z and Y are the standard glass scales but the X is a lower profile glass scale to stay below the table surface.

Options have changed a bit since I installed mine. Magnetic scales could be an option.

HTH,

Rod

I have a vague recollection that the Sharp machine was originally available as a set of castings.

Rod

Hi Baz,

Do you use oil or grease? I just give a few pumps of oil from my Myford gun. I don't recall any sophisticated route for getting grease into the bearings.

Regards,

Rod

Here's a random selection of photos of the mill taken from my various albums. I bought mine new from Town Bent and included the slotter and power feed. I have changed the drive to VFD with 2 pulley speeds which eliminates the rather noisy intermediate pulley. The DRO was fitted a few years ago and I had to sacrifice the stops on the X axis to fit the scale. Any more details that you need let me know and I'll take some more relevant photos.

Cheers,

Rod

The plans cost about £30 new from the various ME suppliers.

Rod

Those are the ones. I'll order a box of ten and we'll discuss who wants what when they turn up.

Cheers,

Rod

Any body else interested in sharing a box?

Rod

Good find but, sadly, need to be ordered in boxes of ten . I'm glad to see they are still available. I could do with a couple of spare tips. I'd be happy to buy a box of ten and split them at cost if anybody is interested.

Rod

Just to confuse the issue, I have one of the "pipless" slanted tips which has 4125 engraved on it.

I'm note sure if there was an official mk I or II designation. Back in 2018 Greenwood were advertising the new KIT-QD version. I approached Greenwood at the Midland show and bought a couple of the previous model (1125) tips for my KIT-Q-CUT. The Q cut works very well but e.g. ARC sell similar systems and they work fine for considerably less money. When my last Q cut tip dies I will transfer my affections to a cheaper system for my rear toolpost.

Rod

That went better than I expected

The 2 original black collars were both loose so I printed all 4. Took a few attempts to get the TPU parameters (nearly) right. I think my filament may be a bit damp but I'm happy enough with the result.

Rod

From a CuBe safety data sheet:

Rod

Edit for previous post "annealed" not "unhealed" (?!*?*!* predictive text )

Edited By Roderick Jenkins on 03/01/2023 17:45:55

I have this copy of a page from ME pinned to my copy of the book

Rod

Brass can be made springy by putting work into it. Half hard brass has been rolled to put some work in. More work makes it springier, annealing softens it. The traditional way to make brass springs is to hammer them. Too much work makes the brass brittle. Copper beryllium can be formed in the unhealed state and then baked at about 320C to promote the spring properties.

Rod

I was fortunate enough to be the only bidder for a 2-6" M&W micrometer on ebay. The blown plastic case liner is in a bit of a state

My 3d printer is not big enough to print the whole thing, so divided into 4 bits

Not sure now about the felt pad in the lid - might harbour damp. 2 of the collars for the standards where missing so I have printed those from PLA. The originals are rubbery so I will have a another go with TPU though not confident of success.

The ratchet thimble is missing from the micrometer head. Although I never use it, I feel it ought to be there. I guess I will have to make a matching ratchet to this

Happy new year folks,

Rod

There are rumours on the knife making forums that some files are case hardened mild steel rather than solid tool steel.

Rod

Niko,

I can't disagree with you from a pedantic viewpoint. However, if you look at the calculated results (Actual) of the Myford thread cutting chart, could a metric lathe of similar size cut a more accurate thread?

Regards,

Rod

Could they be from the Jacob's gear hobber?

https:l//www.collegeengineering.co.uk/product/gear-hobbing-machine-complete/

Rod