Home – John’s model engineering interests
This site covers my interests in model engineering.
The material on this website was, originally, just about milling. As it expand it is organised by the process used to make something. It seems that many people are more interested in “how to” or “how to make” type questions. In this case, it is possible on any page, to use the search option to find something.
There seems to be a difference between “how to” and “how to make”.
“how to make” index see “Make”
“how to”
Processes
Many ways of making a metal component can be classified into three main classes. There is where a piece of metal has its shape changed into that required. In this case the volume of the starting piece and the end piece stay, roughly, the same. There is then where the workpiece is made by removing metal from the starting piece and then, there are processes whereby metal is added to the starting piece.
go to processes
measuring, alignment etc
tools for measuring
measuring problems – links
Pages relating to, alignment , centering etc
computing gear trains
Hobnail – software for computing gear trains
Brocot’s method
Materials – links
Components
go to components – links
Electronics
Something completely different
john f's workshop 
Great post. I was checking continuously this blog and I’m
impressed! Very useful info specially the last part 🙂 I
care for such information a lot. I was looking for this certain info for a very
long time. Thank you and good luck.
Thanks
What was the last part?
john
Thanks for making the effort to publish your knowledge/tricks/tips. Very informative and helpful. You are in my ME faves.
Regards
Stuart AKA Rik Shaw
Thanks
i would like to know if a dovetail setup on a milling machine table can be used up side down.( male top and female bottom) or must it be male bottom female top?
I am not quite sure what you are asking. But this might be it. In principle one mmight think that a dovetail could be either way up but often the length of the two parts are different usually the longer part will be on top. The shorter part is always the female part because the female part always hold the jib and it is desirable that the jib is on the shorter part.
This is, in fact, the usual arrangement for a milling table long table – male – on top short part underneath female with gib.
hope this helps. Let me know if this is not the answer.
john f
Tanks for your respond. I can get a dovetail table from work, it comes from a very robust wood working machine that was damaged in transport but the table is still 100%. Before i striped it from the machine, it looked to me that i would need to turn the table up side down, to use it for a compound milling machine table.(I would like to build a 3 axis stepper motor cnc milling machine.)After i striped the table from the machine, i realized that i can use it as is…. I THINK? Sorry i am new to this site! How do i attach a photo so that you can see what i meen? In short, the long main table with male dove tails is at the bottom and the short table with female dove tail and jib is on top, travelling left to right or right to left. can i use it like this or do i have to turn it around.( i can mount MY TABLE on the female table as it is now, then i will have verry long travel left and right.)
send me a photo to
johnsf23@hotmail.com
john f
Somehow I seem to have missed this comment. sorry. The difference is that the gib is invariably fitted to the female part. This means the female part is the shorter part – the male part is the longer. In the case of a milling table the longer part has to be on top hence has to be the male part.
hope this helps.
john f
thanks, i will as soon as i get my new cell, i will take a photo at work an send it to you. should be thursday/ friday.
As a beginner, excellent info for me! Thanks for putting this online!
Thanks.
Let me know if you have any particular questions.
john
Hi john, Alistair here from shooftie. Going to have a look through your site, glad to have found the link.
Let me know how you get on.
john f
Dear sir,
We need hob cutters of different sizes…
Please send us details
Regards
Umer Munir
Email: madingears@gmail.com
You can buy both metric and imperial hobs for making involute gears from ARC EURO who live somewhere around Leicester.
If you want to make them yourselves there were some articles by Giles Park in Model Engineers Workshop magasine. There are several indexes on the web that would enable you to find the article. If you joined SMEE you would be able to photocopy these for yourself in the SMEE library.
john f
let me know how you get on.
Dear Sir,
we need hob cutters
2 module
12 dp
I am preparing a training guide for CNC and machining operations, for education purpose only and not for sale, and would be available free for trainers / students of vocational training. I found your website vey useful for such applications. I am seeking your permission to include few items to be included in the training guide. Your website reference will given.
Yes you can copy them but you might be better off by just inserting the address of my page in your text as a link.
john f
Hi John,
I was looking at your page on problems related to alignments: https://johnfsworkshop.org/problems-measuring-aligning-and-centering/problems-aligning-vices/ I saw a comment that says: Mew no 182 p40
A Aligning a vice using a DTI
I was wondering, what is this MEW reference? I can’t seem to find it using the Google. Is it a text?
I’m trying to learn some machining basics. I took a class years ago, I definitely need to re learn lots.
Thanks!
John.
Well, I am surprised. I thought this was all written up properly but it clearly isnt.
MEW is Model Engineers workshop. But the article quoted is useless.
I thought I had written the solution but it has been overlooked.
I will have a go at this section and will email you when I have sorted it out.
I have done this particular problem search ” parallel, angle plate, square”
Theres no photo yet. I’ll try and do this this w/e and update the page next week.
john f
Hello John,
I came across your website while searching for information about straight jib strips, it was related to a member in a yahoo group, I have passed it on to the poster in the group, I figured it would be easier and more detailed than my trying to explain it to him, this evening going through your site I came across tapered dowels, and it occurred to me that they never seem to be used in tooling anymore, for instance it was common years ago to attach a ball handle to a shaft leadscrew, but now most hobbyists drill and tap a hole and use grub screws with a flat on the shaft (horrible in my opinion) also the tapered dowel is great in accurately locating two plates together, (if the lineup is out) you can always reset and taper ream again, not so with straight dowels, so do you think you could do a piece on the versatility of the Tapered Dowel
Yours respecfully Walter Maisey………..Alberta
Nice to meet you John and to visit your workshop. Also to see your very useful site.
You can see some of my photographs and how they are organised at my website below.
Best wishes
Des
Thanks. I will.
Looking for change gears, 22mm id, 5mm key, 16mm wide. The few I have appear to be 20dp. Or, I can make but need nmbt40 22mm arbor for my horizontal universal mill (HERO 1C). Or, 7/8″ shaft gear cutter source. Can you point me to a source? Thank you,
In the uk, I would go to homeworkshop.org.uk and ask.
john f
Thanks very much John. Next month when I have a little more time I am going to do a reverse engineer of my unit and create some schematics and service data on calibrating the unit. I will pass them on to you when done. Am am hoping to interface a Mitutoyo 519-521 lever probe to mine. Yours seems to work ok with a single probe. What is the make of leaver probe in your picture?
Cheers
Pete
I want to make a gear of 25 teeth and I have a bowl of odd numbers. The ratio of the device is 1/40
Bowl?
have you got a plate with circles of holes in it?
john f
John,
I visited your site in 25/10/2016 re “Tapered Dowels” and their usefulness over straight dowels, it is now 29/10/2018 and I notice you made no reply I am assuming this was an oversight,
Can you remind me what your question was?
john f
Hello John,
I came across your website while searching for information about straight jib strips, it was related to a member in a yahoo group, I have passed it on to the poster in the group, I figured it would be easier and more detailed than my trying to explain it to him, this evening going through your site I came across tapered dowels, and it occurred to me that they never seem to be used in tooling anymore, for instance it was common years ago to attach a ball handle to a shaft leadscrew, but now most hobbyists drill and tap a hole and use grub screws with a flat on the shaft (horrible in my opinion) also the tapered dowel is great in accurately locating two plates together, (if the lineup is out) you can always reset and taper ream again, not so with straight dowels, so do you think you could do a piece on the versatility of the Tapered Dowel
Yours respecfully Walter Maisey………..Alberta
As far as I can tell parallel dowels are always used for aligning two flat surfaces to each other. These might be two castings or a jig and a workpiece. also a tapered dowel is only used for fixing a part to a shaft.
I think the difference is that a tapered dowel will lock if hammered in hard which is what is required where something is fitted to a shaft. On the other hand parallel dowels will never lock and this is essential usually where two parts have to be aligned to each other and when they might have to be parted.
Let me know if you agree or not.
john f
Hello, John,
yes, I do agree with you and the use of parallel dowels, my having spent many years in the toolroom I guess I didn’t explain very well in my original question, I should not have mentioned the tapered dowel is great in accurately locating two plates together even though it would work, straight dowels used in tool and die are just for repeat initial location and the holes can get damaged, even dowels can siezed in tight holes with repeat removal and in the case of regrinding of tooling it is no guarantee that punches are automatically lined up, like all things in this trade there are so many variables, so many ways to skin a cat,
An example for a tapered dowel over straight, I have Taig machinery and the mill vertical column is located to the base by a register in a fitted recess with a bolt through the centre, not a very rigid design and easy to lose its tram on a heavy cut, I decided to add a dowel in the side where the two clamping faces make contact to eliminate movement of the column, I used a tapered dowel rather than straight because I did it by hand and elec drill and once a tapered dowel is loosened it pulls out easily, my point being if ever I lose tram or damage the hole I can reset the tram and then re-ream the hole, can’t do that with a straight dowel unless you have oversize reamer and dowel, I have also used tapered dowels in blind holes in tooling I have made,
A tapered dowel should never be hammered in hard, it is not really necessary the one-degree taper will do its job unless vibration somehow is involved, but then again tapered dowels can have threads at either end for locking or removal,
Edmund
I looked this up in machinery handbook. What I said seemed ok as far as it went. The difference was where the highest possible accuracy was required tapered pins were preferred.
john f
Dear John,
we are writing to you from our head office in Germany. We have a product ”Quick Clamp” for milling machine table. We would like to know if you can write an explanatory article about our product which we can use on our website?
The article can be like your following article:
https://johnfsworkshop.org/home/processes-links/processes-removing-metal/the-milling-machine/the-milling-machine-workholding/workholding-clamps-and-clamping/
Yes, of course.
You can email me at johnsf23@hotmail.com
john F
John – I’ve been looking with great interest at your writeup on machining convex and and concave radii on a milling machine using a fly cutter and a rotary table. However, the text makes reference to “Figure XXX” in explaining the process, but Figure XXX seems to be missing. Can you help?
you are absolutely right.
I used to spend a lot of time on this website. Often pages were put on with photos to come.
But as it got bigger it got out of control. Mainly there was no way of managing large numbers of photos.
This is one of those. The drawing never existed. But I do have a photo of this I will try and send to you.
however if you have any particular problem do
email me.
john f
John,
Thanks for your prompt reply. Hopefully the photo you are sending will come through fine via email. I will let you know when I receive it. Thanks again.
I cant find the original file but I have found a real photo! I will try a make a copy and email it to you.
john
Thank you!
hi john
what size is the sand casting mould you have?
I had two similar mould boxes. each consisted of identical drags and copes. Each bit was about 10in x 10inx 3in so the whole of each box was 10x10x6.
I was thinking I never used them and sold them for £40 for the 2 boxes.
hope that helps
john
is it still possible to obtain a copy of the Hobnail gear calculator please i am restoring a old Jacobs machine thank you
did you get a rely to this?