Member postings for Buffer

Does anyone have any good advice on creating your own scale drawings of complex projects from pictures of the original and full size drawings? I'm trying to do this for a piece of artillery and it's so hard. As an example everything ends up as decimal inches and not the fractions you normally see. Nothing just matches up with available sections. Do you just modify your bits to fit what you can get and no one notices? Should you just make bits that look and feel right rather than are absolutely to scale?

I have been tinkering with fusion and solidworks but to be honest when copying an original its pretty hard to model parts unless you have a drawing to work from which is a bit of a catch 22.

I'm sure a lot of you will have done this sort of work and I would really appreciate any advice you have to offer.

Many Thanks

Stuart the rod lying around might be the problem lots of guys wont use stuff unless they know what it is. Also I seem to get my best finish with HSS. I can hone it with a diamond lap and then take a nice light cut with lots of cutting oil to bring it to size and finish.  I normally use a tangential tool for this.

Edited By Buffer on 19/01/2021 19:59:57

It was Wife's turn to teach the kids so I sloped off for a few hours. I got the flywheel made by fitting it onto the centre shaft then used that in the lathe to turn the flywheel to size. It needs a square ended slot through it for the drive pin. I drilled out most of the slot then just finished it off with a slot drill. It went nicely as it's a cast iron flywheel.

This is exactly the sort of reason why I want a filing machine. The slot is supposed to have square ends and I hate doing this sort of job.

I used a Stevenson's Block to cut a square on the end of the drive pin. it was dead easy with this great little tool.

I then milled six flats on the end of the drive rod again dead easy with a Stevenson's Block from Arc. However this turned out to be a less accurate item than I had hoped. The flats weren't all the same size which was annoying. It wasn't a lot but it was enough to be visible.

I then just had to slot the base to fit the Myford cross slide and I could fit it and give it a spin. It was easy to fit but you have to be really careful to make sure you don't give your lathe bed or saddle a good wack. The tool has to be carefully fitted so that the sliding part goes down between the ways. I then locked the saddle and cross slide. The lathe was put in its slowest normal speed with the clutch slowly eased in and away it went.

There's not much more to go now Its really just the fittings to hold files and the aluminium bow for the saw blades. I've got two days of school work now so I guess I wont be out again until Friday.

Its been a while since I posted on here. I wasn't able to get anything done until recently as I had the dreaded Covid over Christmas. I felt so unwell and I have only recently felt well enough to get back into the workshop.

So I got the connecting rod finished. It wasn't difficult I just drilled and reamed the holes to size and then pushed the bearings in using the vice. I roughly shaped the ends in the milling vice using a pin through the hole and then finished by filing.

Here it is fitted to the rest of the machine. It's very important that the six screws are countersunk below the level of the surface, there is virtually no clearance of this crank over them.

The flange on this pin has to be made accurately or even better slightly thicker. If you get this wrong you'll have to make it again or fit a washer. Funny thing is it's not given on the drawings you have to do the maths to get the size which to me seems a bit odd for such an important dimension.

Noel I don't think I made myself clear with my question to you. Are you saying that if the molten brass touches any left over PLA in the mold then there could be an explosion similar to molten metal on water?

Noel. Would the result of pouring metal on pla be similar to water?

Neil

I thought this was a very interesting article and its something that I will definitely be trying. I had no idea that plaster of paris could be used for this.

Could you just explain a bit more about using a metal wire across the spout to hold back dross. Does it all just stick to the wire and the brass flows out under it?

Thanks

I have to do it because my chuck wont close down less than about 1/16 th and it's a real pain. Does anyone know where I can get a chuck with a taper for a startrite mercury? I think it's a j33 taper from memory and not easy to find.

Edited By Buffer on 06/01/2021 15:36:23

I use Mac Models and M-Machine-Metals for my modelling supplies. For large stuff when I made driveway edging and plant supports I used F H Brundle who delivered it in 6m lengths that week and were a fraction of the price of the good old metals4u.

I phoned up early in the year and asked about a piece of steel. He said yes we've got that. So I went down to get it. The guy then spent about 20 minutes climbing over rusty piles of off cuts spread all across the floor. It was all in the most chaotic unit I've seen. He was licking his thumb and trying to rub the rust off the end of bars. He finally found a rusty piece of what he said was the steel I was looking for. I asked how much expecting it to have been about £30 from looking online elsewhere, anyway he came back and said 150!! And there was no guarantee it was anything other than a bit of old rusty mild. So I made my excuses and left never to return.

Nigel I have just sent you a message.

Well it seems there might be a little error in the drawings.

The screw that clamps the swivel up tight impacts with the the casting. I might be trying to tilt the table more than it is designed to do but made to the drawing it does hit the casting. It's not a problem yet as I think most of my filing will be done at ninety degrees. But if you want to tip the table over a a fair bit then make the thumb screw longer or make the tommy bar loose like you would find on a vice.

Thanks guys.

Well Wifey went to work today and the kids seemed happy scrapping with each other so I sneaked out to get another bit knocked off.

Now the instructions do say that you should give the table a skim over to get it flat. The piece is punched out so it has clearly taken on a bit of a curve. It's not obvious by looking at it so I wouldn't worry if your 4 jaw can't cope but mine can so I gave it a long going over. You can clearly see here that the middle is a bit lower than the edge. It's not a lot though probably less than 1/2 a mm.

This is the other side and its pretty obvious but the middle is now being cut before the edge. I only cut enough to get a flat surface for the casting to bolt to it.

A while back while I was making the smoke box for a loco I did what some might see as vandalism. I drilled into my best four jaw chuck so I could mount posts on it. I know I could have used soft jaws and I do have a bearing mounted on a tool post but I did it anyway and it has been very useful.

I used an old bearing outer as a parallel whilst drilling the mounting holes. I could of used normal parallels just as easily but there is an agricultural engineering business behind where I live and they always chuck big bearing in the skip so why not.

I got a bit more done last night. It wasn't the easiest to set up as the centre of the arc is off the casting by 3/16th of an inch. With hindsight it would have been a lot easier to just slip a piece of 3\16th steel between the casting and the angle plate but I only thought of that this morning. Anyway I got a good piece that fits very nicely to the main casting.

The main casting needs a curved slot with its centre 1/2 an inch off the casting in the fresh air. So I took a little bit off the top of the casting to get it to the exact length and then pushed it up to a 1 inch cylinder that was in the middle of a rotary table. I centred the table using the Osbourne manoeuvre. This works really well and I only had to do it 3 times and it was bang on as far as I could tell.

I then flipped it over and fixed it to an angle plate squared it all up and drilled the holes to hold the guide bars. I was really pleased when this came out spot on as I didn't mark out any of the locations just used the dro.

So that's it for now, back to work tomorrow but hopefully I will get a little bit more progress in the week.

Edited By Buffer on 13/12/2020 18:55:26

The 5 tooth shell mill actually gives a very nice finish when you want it too but I knew I was going to scrape this bit so I didn't hang about with it.

This is the casting after about an hour with the home made scraper

So I got some work done on the machine this weekend.

The piece below is the bit that goes up and down sliding on the main casting. It is supported and guided by the bits above. I rubbed it on the surface plate and as you can see there is very little contact.

After about half an hour with a carbide paint scraper blade that has been soldered to a length of steel rod it looked like this, which is looking much better.

This is the main casting that was cut with a 5 tooth carbide shell mill from Arc

Hi

I thought I would post a few pics and some info on the Filing Machine from Hemingway Kits.

This is what you get plus some build notes and good drawings.

Edited By Buffer on 11/12/2020 19:49:32

Edited By Buffer on 11/12/2020 19:50:01

With regards to the container ship loading. Anyone who has been in a rowing boat ( or kayak) will have first hand knowledge of just how high the c of g can be with what seems like very little under water and still be perfectly stable. But as we all know stand up in either and it's a different matter.