Member postings for Johan Crous

Noel, I have done some crazy stuff in my life. I am sure I will think of something. I am now busy with an endmill jig that use a MT3 collet chuck ean therafter I will tackle this. I will keep you guys up to date.

Thank you.

I am looking for a plan to construct a radius jig for the Harold Hall grinding table.

I would like to grind radiuses on HSS tool shafts and I would like to sharpen ball shaped milling cutters. I am thinking in the line of adding the Harold Hall end mill attachment on top of the radius jig or the other tool holeder to clamp HSS rods or shafts.

A picture / photograph from where I can get an idea will also be appreciated.

Thank you Joseph,

Pierre was very helpful and and I will get my CBN wheel tomorrow.

I will recommend his services to anyone.

I am about two thirds completed with the basic grinding rest of Harold Hall.

I noticed, as designed, the table have almost unlimited in tilt forward and backwards, but very limited to left and right.

With a few small changes to the bottom half of the design, it will be able to tilt just as must to the left and the right as forward and backwards.

Is it really essential to be able to tilt left and right much?

I am going to implement one of the two changes, as I feel it will make my life easier. The other one depends on the answer.

I will show my mods with a pic or two when completed.

I am in the process of building Harold Hall's grinding rest, along with others as well. I am now also making the grinding head as Mr. Hall described in his book, by using a bench grinder.

I could not yet find a form 11 Norton wheel in Cape Town. Everyone is sold out.

I am now thinking of buying CBN and diamond wheels at Amazon.com.

What grades must I buy? The Aluminium Oxide was 60 grit, but the CBN comes out in several grades. I bought a 150 mm size bench grinder, but I can still use as small as 100 mm wheels.

I agree with you John Although it works great, not everyone have that money to spend.

Although I use ViaCAD 8 Pro (PunchCAD) as mentioned (it can also render and show everything in 3D as well as imports), there are freeware equivilants like Blender 3D (3DS Max equal) - it can do rendering and animations as well. Then you get FreeCAD as well - How good I do not know.

A relative affordable alternative is TurboCAD, but the Pro is getting expensive. There are also a few software giants that allow free student or amateur users to use their products with a few limitations.

I am using ViaCad Pro 8 and have 7 as well.

This CAD is produced by PunchCAD. You get consumerCAD: the standard and the Pro, Then you get professional: the Shark lite and Professional.

I am using this now for more than two years and will recommend it to anybody. The learning curve with the video tutorials build in, is reletive easy. Thereafter it is easy to figure things out (for a person not used to 3D CAD) and the forums also give very good assistance.

Th program may be small, compare to industry giants but for what I do, I could not get better. I design everything myself in real size befor I try and in different colours. It is then so easy to see if it will work or not.

Once I have bought ViaCAD 7 Pro, the upgrade to 8 was only half the price. I cannot wait for 9 to come out. Money well spend. 9 onwards will be full 64 bit and 32 bit, but 8 and earlier is 32 bit, but functions perfectly in both Win 7 and 8, and 64 bit.

The program imports other format relative well. When I design for example a Belt sander, I import the elctrical motor and the pillow block bearings and maybe some of the grub screws. No need to redesign everything from scratch. I recently had to draw a 12 inch bicycle wheel for a hand pushed hoe. I imported it perfectly.

Edited By Johan Crous on 19/12/2013 10:12:18

I bought such a bender today:

http://www.amazon.com/Universal-Bender-Bending-Metal-Square/dp/B0081TLV5A

I need advice to mount this bender so that the handle be moved up and down and not side ways.

I am partially disabled after a series of surgery and several to come (Hopefully I will heal completely}. In the meantime I am a bit limeted.

I would like it if the mount can be portable.

Any ideas?

I have seen countless examples where aluminium was used in stead of steel and it worked. Not so hard but working.

I have now seen this web page : **LINK**

The owner is using Brass (although more expensive, it is possibly more durable)
Take for example a brass tap. The mechanism is rubbing against each other for very long years and it still last.

Here he made tool holders for a QCTP: **LINK**

Here parts of the T & C Grinder: **LINK**

Parts of this grinding rest: **LINK**

QCTP: **LINK**

A lot here: **LINK**

Boring Head: **LINK**

Advanced grinding rest: **LINK**


I just want to know what is your opinion on the use of brass. It will machine easily on my mini mill. I just don't know how durable / hard it is.

Will I be able to cast in brass?

I have run it now while cutting a deep dovetail for a QCTP tool holder. It is working like a charm. The fluid coolant prevents it from heating up. The swarf produced is razor sharp splinters as the carbide tip is a very sharp, very positive raked tip. The finish is very smooth. It is just slow on my mini-mill, but I am getting there!

I have run a long dovetail cut with my homemade dovetail cutter with a single carbide tip. The motor is not getting hot, only moderately warm.

There is one further need, and that is perspex sides as splash covers. The dovetail cutter makes a mess!

I have milled for about an hour today. The motor keeps moderately cool and the cutter remains cold. IT works, even for a homemade carbide insert dovetail cuter. However I have ruined the cutter that ran too hot before the coolant. Tapping fluid as a coolant did not cooled it down enough. The cutter, after sharpened will again be excellent for aluminium and brass.

Any pics?

OK, here is my humble attept:

First, I have used a 17l bucket, cheaply bought from Plastics for Africa. The nearest I could get in the shape that would still allow the garage door to close.

I have added a drip tray that I have painted gray. On top of the mill you can also see the motor cooling system I have added. Now the motor runs cooler as well as the milling cutter.

The mill is mounted on spacers, that I have sealed with silicone rubber seals as well as a lot of silicone. It is not leaking at all.

The drain is from a boat shop. A smaller than usual basin drain, linked with a pipe to the container.

The return pipe I have covered with a T-shirts sleave to catch all steelal swarf. The material is freeflow for the water. The motor is lying loose. I will make a T fitting later to circulate some fluid directly back to lighter the strain on the motor. It is stronger than needed.

The pipe is coupled to a cheap plastic coolant spout set. Easily and very cheap to replace. This whole set-up is the price of one milling cutter.

Here the coolant is running at the rate I like currently. Time will learn if I should adjust. The flow is aimed on the workpiece, well away from the cutter, but the cutter get enough fluid to stay almost cold, but without the rotating cutter spattering water. (OK, OK, OK, I know the cutter is stationary but I have already switched off when I realised I forgot to take a pic of this last step.

This is a cheap set-up. Only time will learn if the motor's seals or the motor will last. Some people say it will not. Other said they have used it some years like that. So the hell with that. I am trying. If it can last at least a year, then I would have got my money back. I will have to drill a drainage hole in the tables side plate, as currently the coolant is damming up in the t-slots. The cover plate can be removed, so a hole of about 6mm will be enough.

Edited By Johan Crous on 23/01/2013 17:06:31

Amix of 1 : 20 soluble oil and water. Greenish in colour.

I am now making an El Cheapo coolant system for my mini-mill
I have made a drip tray of 40mm high with a boat basin drain that will go to a bucket with a piece of pipe. The bucket will be of a size that will be fixed to the side of my mill stand.

Inside will be a fountain water feature pump that will lead the water to a mill cooland spout, equiped with a small tap. I will direct the water to the spot where the cutter meets the work piece. The pump at its slowest setting is a little strong, but closing the tap a bit control the water flow.

The mill is mounted on spacers, on top of the drip tray, equiped with silicone washers. I will also waterproof it further with a proper sealant tomorrow and test the dqay after tomorrow.

The pump can deliver up to a 1000l / hour. I am aware that there will remain a little water in the drip tray that will evaporates during the day because of very hot conditions, as well as due to spatter, but the loss will be minimal. At least now my cutters will remain cool.

Any other ideas? Any points I have to take in account?

Johan

Ultra quiet. As soft as the sound of a notebook / PC.

I have listened to several replies, also to one that said that the motor can still burn out if it gets too hot inside while you may get the external cool. I have decided on a fan and shrowd, but I am too lazy to make a big project yet, as I would like to evaluate first before I do the mod permanently, and only if it works.

I bought a 115 mm extracter fan tha can deliver 76 cubic meters of air per hour and that can run for a very long time. I have set it up to run permanently, as long as the mill is plugged in and the plug switched on, although the machine may be off.

The mill before anything done.

At the bottom of the motor there are four narrow grooves to circulate the air.

On top is a cover that needs to be removed. The little round holes on top is just for show and only air the bearing.

Below the cover there are 8 vetilation holes, but no fan. I guess the rotation of the armature will circulate some air, but very littllow speed, or almost nothing.

Don't laugh. A plumbing coupling fitting for toilet pipes, with a hole cut to allow for the motor's wiring. This fitting is made of white rubber and is flexible. Added to it is a hose clamp. One side ring on the narrow part (nearest to my hand) is cut away to make space for the hose clamp. The ridge is still visable.

Added to the motor with the hose clamp. The motor's wire can be seen extruding through the cut gap.

Air blowing in from the top will be forced through the motor's vetilation holes. None can get past the motor. The fitting will be a tight fir und the extracter fan. No air can escape and the fit is tight enough to keep the fan in place.

The fan in place. The fact that it is white is not so bad in appearance.

The fan's specs.

The current job. Quite a lot of steel to be removed. This will be a parting tool holder for a QCTP. I am cutting the dovetail here. Firt the innitial removal of lots of steel.

AND:

It works! It works! It works!

It did not get hot tonight. Just comfortable warm to the tough. I guess about 40 degrees of C. The fan is kept running in between stops so that the cooling effect may last. The sound is a very soft hum, like a running PC. The air is blown from the top downwards and can observed if you keep your hand close to the motor. Currently I am not interested in colouring it black. White is fine. Now I am not worried anymore.

Thanks for all the advice and encouragement.

Johan