Thread: CNC TTU Build

Hi John,
There are three areas of important in the design. The 6 holes for the Y axis connection, the three holes and rebate for the X axis connection and the relationship between both of those design elements. The rest of the part provides strength for the connection and allows an area for coneection of the ballscrew.

I think any join in that plate will weaken the part and depending on the area to be joined could introduce a variable between the three elements I detailed above.

Given you have a limitation on the size you can machine I would do one of two things.

Make a jig with position pins so that you can index the job on your mill and cut it as a whole unit. This can be done my making two jigs and clamping the ally to one and using the two jigs to index the job or just use the ally and one jig and use the bolt patterns to index the job. I know this will be a pain as you will have to make a dulpicate set as the gantry sides are mirror images and you will have to get your mdf machine up and running to make the jigs. You could test your indexing by making a MDF mock up of the gantry side.

The second option is to position the job so that you can drill the 6 bolt pattern and the 3 bolt pattern and the rebate in one setting then cut the outside on a bandsaw. Print out your drawing and temporarly glue the paper to the ally as a guide.

I am assuming you are going to cut the plate on your mill.

Thanks Rod,

Back to the drawing board. I think I was thinking too hard about this.

My MDF router is still going as the Ozito routers are fairly cheap to swap over. So I may as well do you and Alan suggested. I can get the holes drilled and hopefully the rebate for X Axis plate done on that. Then bandsaw the outside profile. I'll need to double check the 16mm plate to make sure it's reasonably flat when I get home. If not I'll go with the 21mm plate as I know that is flat.

I better get a move on as my MDF Router is going to a new home in Bendigo the weekend after next.

Hi John,
I can see where you were coming from - it is nice to be independent and do it all yourself.
The rebate will be the hardest on your MDF machine so reduce your pass depth to match the Ozito and rigidity of the machine. Test fit the rebate before you de-mount the job as I have found variation in cutters that cause problems. Easy enough to enarge the slot while it is still mounted on the machine.

After much gnashing of teeth, I finally have two gantry sides done.

The outside profile is a bit rough with my dodgey bandsaw skills, but doesn't look too bad after a bit of touch up on the spindle sander.

John,
That will clean up nicely, but the important thing is that you have the rebate and the holes accurate so that everything will run true on your rails. If there is a minor discrepancy in the outside shape, no one will pick that from one side of the gantry to the other.

Keep up the good work.

Cheers,

Alan

I had a model boat meet on this morning so I only got a few hours in the shed this arvo.

I had to prep the stock for the gantry connector plates, which took at bit of time. I did manage to get one cut and test fitted. Hopefully I'll get the other one done tomorrow after work.

I did a bit of a clean up so I thought I might take a couple of pics while things are semi clean (please ignore the collection of "stuff" under the CNC)

The gantry is now mounted and moves along the X Axis The next step is to machine up the mounts for the Y Axis ballscrew and stepper.

Excellent work there John.

She is definately coming together very well. I finally bit the bullet and decided to register on here.

Just trying to determine what I want to build now I have "command approval" for a CNC project.

Hmmmmmm too many ideas, where to begin

Keep up the great work

Johno

Hi Johno,

Welcome aboard! Good to see a fellow model boater here.

There are plenty of people here to bounce ideas off so feel free to start a new thread to refine your plan. There is also a group of CNC'ers over in Perth who should be able provide a demo of their stuff so you can get some good ideas too.

Cheers
John

Busy weekend but not on my build unfortunately.

I spent a few hours on Saturday showing the new owner of my MDF CNC how it all works. He's a member in this forum so we might see him around this CNC section now.

I bored out the pulleys centres on the lathe to fit the shafts on the steppers and ballscrews. Did a test fit with the belts to see how they looked.

I also started on the Y Axis motor mount but have stopped the job as it's getting a bit late. I still need to do the motor pocket and outside profile cuts on the part.

Hi John,
That is starting to look like it will work now.
Interested to see your clamping arrangment on the mill - I know what you are using just can't see from the photo how it is holding down that plate.

Hi Rod. Nothing special on the clamping as it is just my mill vise with a couple of parallel bars to raise the part up.

EDIT: Here is a better photo that shows it is actually in the vise and not floating on top

Oh and got the motor pocket cut this arvo too

Got some shed time in today and the Y axis ballscrew is now mounted. I'll need to shift the bottom rail along so I can centre the ballscrew on the axis.

Plus I need to get a longer belt as I didn't realise this one was longer than the X Axis ones when I got the part files of Rod. That will learn me for not checking, but no big dramas as it will be a little while before I'll need it.

I met up with a guy at work who is an Electrical Engineer and he came and had a look at my machines as he is looking at getting one. He is going to give my electrickery set up a once over after I have wired it all up. This will be great as I wasn't keen on flicking the switch without someone giving it a double check.

Hi John,
Looking good there.