Member postings for Roger Woollett

If you have not done so already join the raspberry pi forum.

https://www.raspberrypi.org/

By all means google first but there is a lot of help available on the forum. Be sure to include the line that gives the error and the erreor message.

It would be worth checking if it is the chuck or the collet at fault. I put a clock on the inside surface of my ER20 chuck and found it to run perfectly true. I came to the conclusion that the cheap collets were at fault.

I have also read that the collets need to be tightened quite hard

Alos buy the biggest rotary table you can fit on your mill. Clamps take up a surprising amount of room.

You are of course quite right. A total of 90 turns is required. Five complete turns for each of 16 teeth takes up eighty leaving 10 turns. Thus 10 holes of a 16 hole plate times 16 teeth gives 10 more turns.

You need five complete turns plus 10/90th of a turn. Thus you need one hole in a 9 hole plate, 2 holes in an 18 hole plate etc. You will have to find a plate where the number of holes is a multiple of 9.

If you are going to create a new topic I suggest "Safety in the Workshop" or something like that. It might put off some of the elfandsafety brigade.

I have a small (Cowells) lathe and use 1/4inch HSS tooling. I don't think rake angles need to be so much different from standard - perhaps a bit greater for steel. What I do find important is to keep the cutting edge really sharp. I use diamond laps to keep tools sharp. Use them little and often.

Roger

HobbyTronics say they have 3 in stock.

**LINK**

I have used them in the past and had good service.

I have only rudimentary electronics experience so we might need help from the more knowledgable. If I read the datasheet correctly each phase can draw 0.5 amps and the coil resistance is 8 ohms meaning a supply voltage of 4 volts. This suggests to me a power supply of 2.5 amps at 4 volts.

This should be within the capabilities of the SN754410 chip I used.

We also need to establish the input to the arduino - what logic determines how many steps to take and how fast.

I will send a PM.

I hope I am not repeating what has already been said but it seems to me that if you do not want to use microstepping an arduino could be used as the controller with some fairly simple external electronics. I have written my own driver code for a simple four wire motor using this technique.

In a five phase motor the sequence of stepping is a bit more complicated. This link

**LINK**

shows that each phase (pair of wires) needs to be driven positive, negative or off. Using a standard h-bridge for each pahses means we need 3 arduino pins for each phase. By using a NAND gate for each phase this can be reduced to two. One pin controls the current direction and the other goes to the h-bridge enable.

I would be happy to help with the programming.

Roger Woollett

If you are going to do a lot then it would be worth considering a collet chuck. ER20 chucks on an MT1 taper are available. For occasional use I would suggest using a four jaw chuck if you have one. You will get a better grip on the cutter and can clock it true.

Roger Woollett

I find masking tape works well. Easier than fiddling around with lots of bits of card or shim.

Roger Woollett

As John says make sure it is not running continuously. I have a bambi and fried the controller so I know. Check the compressor and if it starts getting really hot STOP.

Roger Woollett

You might try Halfords for windscreen washer tube.

Roger

The advice I have been given is "never ever let the tool rub", When drilling keep the pressure on, when turning keep the feed going.

It is possible to use the "create patterns" option of move to give the right number of teeth. In this design the tooth form is just a spline.

Roger Woollett

Peter - there seems to have been problems with registration. If you have managed to register a user name/password I suggest you lo in to the DSM website and edit your profile. I have my job title as Hobbyist.

Save the profile, wait a couple of minutes and then try again to start DSM.

If you have not managed to register at all then do so through the website and then try to start DSM

blowlamp - The open menu shows ECAD, OBJ, SKP, STEP and STL. So pretty limited.

Save as offers AMF DXF OBJ PDF SKP STL XAML JPG and PNG

Roger Woollett

I agree DSM is easy to use.

I have used it for 3D prints very happily. For this design I create 2D dimensioned views and take them to the workshop. They would not satisfy the purists but they work for me. It is still work in progress as you may be able to spot.

Roger Woollett

Installation does seem to be a bit suspect. I also had problems logging in but after a few tries it worked.

On Vista it claims my operating system is unsupported but it still seems to work. No problem on Windows 7,

They have tidied up the user interface and I think now support Sketchup 2014 (but not 2015). Has anyone found any actual improvements?

Roger Woollett

I ordered two carbide drill blanks from Drill Service on Monday. The order came to little more than their minimum for free delivery and I knew they only had one in stock so was happy to wait a few days. Not at all, on Tuesday I got one blank and today (Wednesday) got the second. They cannot have had musch profit left after two first class packets but they do have a very happy customer.

I have bought taps from them in the past and had good service but this is beyond the call of duty.

Roger Woollett