Member postings for The Novice Engineer

I picked up a 2nd hand 1 hp 3 phase motor and a 0.75 kW VFD off E-Bay for under £150 for both. The bargains are there , just got to look and be patient if cost is important. I made the control box using parts from Maplins for around £20. I use CPC Farnell to get my parts now

There was no high pitch whine when running, a very controlled start and a quick stop.

Be aware that some VFD's can have problems tripping domestic RCD's with their inrush current when first turned on.

The combination has worked faultlessly for a couple of years. ........however do not try and run the Myford in Reverse at anything other than slow speed ...... the chucks do spin off ........ !

Steve

Looking for a better way to part off 3" Aluminium [too deep for my parting tools!] and the Kennedy Hexacut hacksaw is only good for 2" .

Looking on this Forum and else where I came across this

https://www.aldi.co.uk/workzone-240v-portable-bandsaw/p/086075229503400

and another version

https://www.scheppach.com/product-details/Bandsaege-MBS1100-scheppach---220-240V-50Hz-1100W.aspx

Its getting packed in my workshop so size is a consideration

Its got to be worth a punt so I've ordered one.

Anybody else used one ?

Steve

I successfully cut some 20mm Al plate on my Draper 350 Band Saw [this is NOT a dedicated metal cutting band saw] with a 6TPI blade, it helps to have a vacuum cleaner to suck up the chips

I also like to clean up any chips that get in side on to the rubber tyres before they get embedded.

Edited By The Novice Engineer on 21/01/2019 23:01:21

My solution to sorting out condensation in my unheated workshop was a De-humidifier that had originally been used to dry out a new build extension.

The machine tools were kept nice and rust free.

As a bonus It collected gallons of pure water, ideal for the steam boiler

I had a reel of Black PLA 1.75mm that appeared to have brittle regions, it would print OK for a while then I would come back and find it had snapped !

I did place it in the slow oven of the Rayburn for a couple of hours to dry out, no real solution it would break again after a few hours of printing

In the end I just put it in the bin rather than spending any more time or loose any more days with failed prints.

IT was the only brittle problem reel I've had in 3 years of 3D printing [Can't recall the make/brand]

I keep my reels in plastic bags with the silica gel bags, and if the printer isn't to be used for a while I will remove the reel and bag it.

Just a quick update.

I sucessfully completed the job using CCGT 09 carbide tool running at 300 RPM with a 30' (0.75mm) depth of cut working dry. The swarf came off cleanly and a dark blue colour. The surface was rough but I was then able to use another CCGT tool at 1800 RPM to clean up the shaft to finish size.

Thanks for all your responses, gave me confidence to get stuck in !

Hi

I am looking for any tips or experience of turning down the ends of a hardened (60c) shaft on a Myford 7.

The shaft is for a 3D printer and I want to turn the ends down from 12mm to 8mm for a distance of 25mm on each end.

I have been trying a few cuts with mixed resullts using a CCMT insert tool.

The core of the rod is soft (ish) and the surface has been hardened and polished.

Thanks

Oh you Too !

I thought it was just me

Steve

Used my CNC mill to make up some tapered wedges to keep the Christmas Tree upright in the Tree Stand!

At long last maybe some thing useful that might keep SWMBO quiet for a couple of hours !

I was given some old cast iron sash weights that had a hard surface like yours.

I cut anend off with an angle grinder and then tested the core with a centre punch to determine the

depth of hard ness, some went to the scrap man!

I then used a carbide tool to get through the surfaces of the ones I felt usable.

Hope this helps

Steve

Maybe the Southern Hemisphere !

New Zealand ?

HI

For my old Kennedy I used a spring from my spares box ...... A Mini accelerator return spring ...probably the same age as the hacksaw!

My Bench tops are 1" [25mm] Block board with 3mm Aluminium. They are around 20years old now and still in good condition.

The Aluminum tops are only held with countersunk screws no glue [ in case I needed to replace them] They were folded up by a friendly sheet metal firm to give a 2" upstand at the back and folded over the edge of the board at the front. I cut them to fit with a Jig saw and metal cutting blade.

From my experience go for the biggest you can fit /afford.

My first mill was Warco WM14 size/style. It was great for doing small steam engines but I started doing bigger and bigger projects and ran into issues with the table not having suffient travel or being able to fit the parts under the head . The final straw .. burning out the motor after being too impatient taking too big a cut.

I replaced it with a Major Gear Head Mill / Drill. Good work envelope and more power for getting the jobs done. If I was going to change I would look at a similar size machine but with a Dovetail column and inverter speed control.

Just my two penny worth

This maybe an old topic but still relevant to keep updated.

I have problems with VFD's [Variable Frequency Drives aka Inverters] tripping RCDs in the workshop . It seems worse with an RFI Filter wired before the VFD [some units have the Filter built in so can't be bypassed.] . In the past I have put the VFD on to a Non RCD protected circuit [Industrial Practice] but with a change of workshop this hasn't been possible [easily!] so I have been looking a bit deeper into the RCD topic

Recently I came across this article that should be of interest. Besides the sales push there is good information The Type F RCD has been specifically developed to cope with Motor inverter drives

**LINK**

So far the target price looks around £150 [compared to ~£25 for a good quality Type A RCD]

Another short article explains some of the difference between the differing Types of Circuit Breakers and RCD's

**LINK**

The other information that I have discovered is that Type AC RCD's should never be used with an Inverter, they are designed for lighting and heater loads.

The Type A RCD should be used, or preferably Type A-APR RCD.

There is also another type recommended called a Time Delay RCD and this is designed to cope with the transient surge typically from an Inverter at power-up. Though these are not easy to find and do come a bit pricy as the ones readily available seem to be 100Amp whole house protection [allowing local downstream RCD's to trip without plunging the whole house into darkness], I'm aiming for a 32 Amp version for the workshop/garage.

Trust this might be useful.

Steve

I've had cataract operations on both eyes and on recommendation from the surgeon I have one lens set to long distance [ miles] and the other set for close [arms length].

It didn't take long [hours] to get use to the set up and find it very easy to do just about anything, Driving, games , using computer, shopping , reading etc... the only issue is in the workshop I need a bit more clarity to see what I'm working on in the vice and machines and to check things close up, for this I have a pair of Intermediate/Reading Glasses [ . I'm thinking of getting Vari-focals so I don't have to push up or look over the glasses when away from the bench].

I've been short-sighted and wearing glasses or contact lenses since I was 10 [Varifocals for last 15 years] so the freedom to see clearly with out them has been great, especially in the morning .... no groping around to find the glasses!

One issue I did have [with both eyes] about 6 months after the cataract operations the vision started to blurr ... this was due to a membrane in the eye growing over the lens. This was cut away by YAG laser in about 30 seconds at the Eye clinic with full vision restored after the eye drops had worn off [hours]

Steve

The clamping force of the bolt is achieved by 'stretching' the bolt and the greater the free length that can be stretched the easier it will be to tighten. The 'taper' hole can be formed by relievng the first couple of threads at the top of the tapped hole.

Steve

Edited By The Novice Engineer on 04/03/2013 22:30:18

Looking at the information

LINK

4 x m6 is best ...though if you can fit 3x M8 you will get around 50 % increase in the clamping force

As a rule of thumb the depth of the tapped hole should be at least 1.5 x thread diameter or you will pull out the threads as you tightened the HT bolts.

You could also use some loctite on the joint ...... belt and braces

Some good info here

LINK

Steve

Edited By Katy Purvis on 06/03/2013 09:31:23

Update

After buying some castings on E-bay ......that turned out to be for Rob Roy ....I bid on another lot that came with a set of drawings for Juliet and a bundle of cuttings of the original articles ...plus as a bonus a typed up copy of the articles !!

So I have all the information .... and a good collection of castings . that will keep me occupied for a while.

Hi

I had a similar Chinese Mill that made horrible noise at speed and kept cutting out.

Turned out to be worn out /broken carbon brushes and burnt communtator.

I replaced the brushes and skimmed commutator ......fixed my problem.

I had read that some folk had replaced the early Chinese controller electronic boards with USA or Twianese manufactured items.

A friend has recommended that to check on the board to see if there is a current limit control. That will control the torque the motor willl deliver.

I had considered changing the DC motor for an AC 3 phase with an electronic controller. but thats another project .....

Good Luck