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Member postings for Roderick Jenkins

Here is a list of all the postings Roderick Jenkins has made in our forums. Click on a thread name to jump to the thread.

Thread: HSS or CS taps and dies
20/05/2019 13:32:33

All the above is true. I am a great believer in CS taps but there is no doubt that they are generally more brittle than HSS so are more inclined to break in the smaller sizes. This happened to me recently with an M3 tap into mild steel. The lump was awkward to hold in my tapping guide so I was doing the job by hand in a vice. The plus was that because the tap was CS I was able to heat the whole assembly up to red heat and drill out the now softened tap. Mind you, when I bought a replacement tap it was HSS.frown

I've never claimed to be logical.

Rod

Edit: Why am I so crap at proof reading my own work?

Edited By Roderick Jenkins on 20/05/2019 13:34:20

Thread: indexible internal thread cutting tool
19/05/2019 23:52:53

I use exactly the same tool from RDG. Generally I get good results, usually winding the spindle by hand. Tougher materials like silver steel do tend to have a burred up finish which needs a bit of work afterwards to clear up the crests with a file. I suspect it is your hydraulic tube that is causing the problem. As has been suggested, you may need a rather more frightening speed to get a good finish straight from the tool. Perhaps the in to out reverse method as advocated by Jason may be the answer.

Rod

Thread: stamford show vandals
19/05/2019 17:32:56
Posted by Plasma on 19/05/2019 17:12:13:.

One can only hope they get their just desserts in some other way.

I don't think they deserve pudding wink

Some people just can't stand to see others achieving something. How sad.

Rod

Thread: Nickel Plating Brass
19/05/2019 16:50:34

My attempt a nickel plating was all done at room temperature with distilled vinegar from Sainsbury's and some sheet nickel from ebay.

The driver was this ebay purchase. Sadly I didn't take any before pictures but this is the ebay pic.

lorch slide before.jpg

About 50% of the plating was falling off and much of the metal underneath was rusty so I scrubbed as much as I could off and then dunked the major component parts in Evaporust. A further scrub and wash before plating which worked fine even going into the pits left by the rust removal. The handle went particularly well. It has all been buffed.

lms3.jpg

The new milling spindle was fabricated from a piece of steel plate (probably EN3B) and a length of FC mild bar.

lms1.jpg

These 2 bits were silver soldered together and then dunked in brick cleaner (HCl) to remove the flux and scale. After that they were plated in the Nickel Acetate solution

plating.jpg

I was interested (and slightly annoyed) to see that the flux/acid combination has etched the surface of the FC steel but I am still happy with the result.

lms2.jpg

I don't know how well stuck the plating is but it did at least survive a trip to the buffing wheel.

Rod

Thread: Thread Pitch Info.
19/05/2019 16:06:46

Alan,

Just a point for clarification: UNC, UNF, Metric coarse, Metric fine, BSF, BSW and BA are all standards that are really meant to define sets of fastenings - basically nuts and bolts.

Threads for things like lathe noses do not necessarily follow these standards so your thread is not necessarily a UNC thread. If it is American (unified) it will have a 60 degree thread angle (as will metric) and if it is a British (Whitworth) thread then it will be a 55 degree angle. So looking at a set of thread tables for a near match will not necessarily give you the right answer. I think you really need to measure the thread angle: A couple of bits of card cut to 55 degrees and 60 degrees will tell you what you need to know.

Having said all that, It us usually the register rather than the thread that is important in getting a good fit so a slack thread of the correct pitch but wrong thread angle will probably be fine.

HTH,

Rod

Thread: Warrington Model Engineering Developments
19/05/2019 13:52:24

Intriguing. I've got a WMED power cross feed but have never heard of the Easychange. Is it possible to get a picture of the unit from the VMCC poster? Is the 17t gear the standard 20DP 14.5 degree with a 5/8" bore and 1/8" keyway?

Rod

Edited By Roderick Jenkins on 19/05/2019 13:52:53

Thread: Grizzly Beers
19/05/2019 10:26:12

Break a leg.

Rod

Thread: Work Holding For CNC Milling
15/05/2019 14:27:49
Posted by John Pace on 14/05/2019 20:12:07:

I use these simple fixtures for these sort of jobs seen in an article
in Mew January 2015 " Cnc fixings" .

Yikes! - that's the one with me on the front cover blush

Thread: Nickel Plating Brass
15/05/2019 12:08:50

I've had recent success using home made Nickel Acetate following Geoff Crokers method on Youtube

**LINK**

Rod

Thread: Work Holding For CNC Milling
15/05/2019 11:53:32
Posted by Martin Connelly on 14/05/2019 18:33:52:

Connecting rod?

Martin C

Brain fart - sorry

Thanks, guys, for the comments. I drilled the 2 holes using the DRO on the manual mill and then transferred to tee bolts on the CNC mill table - not accurate enough needs reamed holes and accurate pins but I basically used Jason and Andrews recipe. I like John's fixtures, I'll look out the MEW back copy.

The 2 1/2 D CAM from Denford is pretty basic and I had to fiddle around with variations of the DXF file to get the CAM to understand where I wanted to cut. Fusion 360 has a Denford post processor so I need to watch some more of Lars Christensen's videos and dive in.

I'm wondering whether the Blue Tape and Superglue method (video here ) might work with a blank which could be drilled (with the end mill) to reaming size, profiled, recessed, removed for reaming and then flipped over onto John's pins (which would need to be set up exactly on the X axis). I might try that out on something cheaper than my precious H15.

Cheers,

Rod

Confession : something went wrong, probably with my depth setting, on the final cut and the end mill drilled a hole in the middle of the web before I could stop it. I photoshopped it out to avoid complicating the initial question. blush

14/05/2019 15:46:41

This is the crankshaft for my Farm Boy engine.

con rod.jpg

The big and little ends still need to be bored out to 9/16" and 5/32" respectively. It's about 5" long and 1" wide, 3/8" thick. Having made this on my Denford/Sherline mill I'm not terribly happy with it, partly due to the software - which I can address but also to my work holding method.

So, how would you go about mounting this on a CNC mill, bearing in mind that it needs to be flipped over since both faces are the same?

Cheers,

Rod

Thread: Myford Clutch Lever fouls the Belt Cover
14/05/2019 09:45:13
Posted by Phil Boyland on 14/05/2019 09:16:35:

Something sounds wrong to me with what you have described as on mine (84 green model) the drive is disengaged when lever to the right. Even when engaged it does not foul on belt cover.

Edited By Phil Boyland on 14/05/2019 09:18:14

Mine, early 70's, does when engaged. There's probably some variation in the angle that the lever is set to on the shaft.

Rod

14/05/2019 09:05:39
Posted by Mike Donnerstag on 13/05/2019 21:11:55:

Just as an aside, I still have a single phase (no-variable speed) motor, and use the clutch all the time instead of stopping and starting the motor all the time. I assume that those that have 3-phase and a VFD would leave the drive from the motor engaged all the time, hence the lever being to the left, potentially fouling the belt cover. Am I right?

Mike

Not in my case, I use the clutch all the time and use the VFD to change speed or direction ( so dangerous but, hey devil         

Cheers,

Rod

Edited By Roderick Jenkins on 14/05/2019 09:06:10

Edited By Roderick Jenkins on 14/05/2019 09:09:43

Blooody winkie 

 

Edited By Roderick Jenkins on 14/05/2019 09:10:48

Thread: The Workshop Progress Thread 2019
07/05/2019 15:47:42

Machined the cylinder for my (air-cooled) Farm Boy hit n miss

fbq.jpg

Rod

Thread: 6" EME rotary table
05/05/2019 23:20:16

Have a look at Walter rotary tables on the net, they look very similar. Made in Germany. East or West?

Rod

05/05/2019 17:48:22

Have a look at the lathes.co.uk pages for the Unimat and EME lathes. EME seem to be a subsidiary of B J Elliot of London and imported Emco machines and Taiwanese mills. I imagine that Taiwanese rotary tables as well as mills could have been imported. The style of the badge on Henry's rotary table looks similar to some of the unimat labels. Not that any of this means that the products were anything but high quality.

Rod

Thread: Anodising
04/05/2019 20:28:14
Posted by 34046 on 04/05/2019 19:29:35:

Doug

15% is available from a google search.

Link please.

The UK law on possession of explosive pre-cursors

Rod

04/05/2019 16:07:13

I've been having a first go at anodising. I've been intrigued by a few comments on the web about using Sodium Bisulphate as a substitute of Sulphuric Acid. My setup is a 30V 5A bench power supply and some lead cathodes in a plastic food container.

anodising set up.jpg

I used a commercial dye bought, like the Sodium Bisulphate, from ebay.

Results are as follows:

anodising.jpg

On the left are the first attempt in 25% Sodium Busulphate. A 720 rule calculator suggested 0.3A for the size of specimen. Very disappointing. I used some Ti wire to support the specimens and it seemed to be very difficult to maintain a current flow.

I have some legacy Sulphuric Acid which I have diluted down to the legal (in the UK) 15%. The middle specimens were anodised in this solution at 0.5A and I used Al suspension wire. Very happy with the results.

I then tried again with the Sodium Bisulpahte but with Al suspension wire. Again, it was tricky to get a really good contact with the specimen to achieve a current to flow. The maximum current I managed was 0.3A with the voltage turned up to the 30V max. The result was the specimen on the right, indistinguishable from the middle specimen.

I'm afraid the "experiment" was not very well designed - too many variables changed at once but it does seem that, given the right conditions, Sodium Bisulphate does work for anodising. 15% Sulphuric Acid is also perfectly good and would appear to be a little easier to use but not so nice to handle and store. I also don't know where one could buy even the legal 15% solution.

Anyway, I hope this helps anybody wanting to do some home anodising. Look out for model engines with purple heads and spinners.

Cheers,

Rod

Edited By Roderick Jenkins on 04/05/2019 16:08:48

Thread: 6" EME rotary table
03/05/2019 21:47:37

EME were importers of the unimat lathes, I rather suspect they were essentially badge engineers.

Rod

Thread: Help on a Matador four stroke engine build please.
01/05/2019 20:13:47
Posted by Kevan Gillings 3 on 26/04/2019 18:36:31:

do you have a photo of your motor ?

Kevan

Well, you did ask frown

matador kit.jpg

Needs a bit (!) of refurbishment. It used to run very nicely...

Rod

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