Erich's Benchtop Gear Hobber Project

[ErichKeane]

So, I am travelling next week, so I wanted to get to a good stopping point. SO, I worked a TON this afternoon.

First was finishing up the hobber spindle housing. I need a bore for some bearings, plus some holes for the clamp that holds the bearings in place:


A boring head + the DRO made short work of those things

Next, in order to get it to bolt down more nicely, I flattened the mounting flange:



After that, a test fit:


Next,I need a quadrant for the hobber side. I used my fixture plate to flatten it best I could. The dimensions in the plans for thickness weren't possible due to the castings thickness, so I just did my best to get it cleaned up here.



I used the fixture plate for a everything on the part I could, including the big bore. I got a bit of chatter, plus idiot marked my fixture plate, but was able to clean it up enough. The big bore is a touch oversized, but it works out in the end.

Finally, I had to make the clamp, which was a facing op, drill, tap, counter drill, and slitting saw. The setup is a little scary, but I took it easy and had no problems.



So, that is ALL the castings complete! As far as I know, there are no operations left for those!


Next I think I'm going to get the lead screws squared away. Off camera,I cut them to length and glued on an extension, so I have to turn those plus everything they goes on it.

After that of course, is the entirety of the drive line, which will obviously be the more time consuming half if this project. I might paint the castings soon though, just to get them protected.

 

[ErichKeane]

Figuring I won't have any more time before I leave, and encouraged by some rustish stains on some of the castings, today was paint prep and prime day.

I disassembled and laquor thinnered everything, marking parts that needed to go back together right.

A bunch of tape off plus some grey primer should get it ready.

I intend to paint it Ace Rust Guard Almond Gloss, but I'll have to wait a few days for that.

 

[ErichKeane]

Well, so... the paint went REALLY bad. I started with the grey brush-on primer, which didn't look awful, I did 2 coats, and it seemed to stick well. Then I did 3+ brush-on almond color, and it was lumpy, brush-strokey, patchy, and awful. I didn't bother taking pictures.

SO, I just finished using paint-remover on ALL the surfaces, which caused some surface rust, so I wire brushed off all of that, cleaned everything, re-chemical cleaned it, and did what I should have in teh first place, I sprayed primer on everything. About 1/4 of the parts also got their 1st coat of the almond paint (spray on this time!) and they seem to look alright. Between my trip plus the holidays plus this set-back, not much has happened on this project in a while

 

[brino]

Hi All,

Back in post #36 of this thread Erich said:

I was thinking about just buying a hob in the right size, having the gear set 3d printed, then remaking them all in aluminum as a way of trying out the machine

I've been enjoying this thread so much that I messaged Erich and offered to 3D-print the set of gears he needs.
No charge, I just want two things i) to keep his fantastic project going, and ii) some honest feedback on how they work out.

Erich produced a list of the eight gears that should allow him to generate all the gears he needs.

The tooth counts required are: 38 40 44 46 50 52 56 60

the rest of the specs were given as:
14.5 Pressure Angle
20 Diametrical Pitch
3/8" thickness
5/8" bore with a 1/8" key (i can cut the key with a file, or come up with another solution if need be!).

Here's some pictures of the gears:







I printed them solid (100% infill), so that the required key way can be cut with a broach.

Just for interest, these eight gears used 110g or 16m (3.9 oz. or 52.5 feet) of the 3mm dia. PLA filament.
I got that 1kg spool for ~$25 (including tax), so all eight gears were only about $2.75 in materials.
Shipping them to Erich will likely cost a little more than that (not complaining, just saying!)

Erich I do have a broach set, if you confirm the specs of the key-way you need (is it 1/8" x 1/8"?) I can see if I have the appropriate broach and if so I can cut them before sending them. If you are setup to cut them yourself, then I can get them in the mail. Just add your address to that private message.

Brian

 

[ErichKeane]

I actually picked up the right broach already, so you can just ship them if you'd like. The keyway is 1/8x1/8, but I have purchased the broach and bushing (Just have to hope my arbor press is up to the task!).

I'll PM you the address!

 

[brino]

Just have to hope my arbor press is up to the task!

LOL!

 

[rwm]

So cool. I love the idea of cutting these in aluminum now.

 

[Winegrower]

You can get a set of 8 cutters with these DP20 specs for about $76 on eBay. I have purchased a Mod 1.5 set that I used for some Delrin gears…aluminum seemed like it would be no problem.

 

[ErichKeane]

You can get a set of 8 cutters with these DP20 specs for about $76 on eBay. I have purchased a Mod 1.5 set that I used for some Delrin gears…aluminum seemed like it would be no problem.

You found 8 gear hobbers for $76? I picked up the cheapest one I could find on ebay (hence 14.5 PA/DP20) and it came out to $100 for one!

 

[Winegrower]

You found 8 gear hobbers for $76? I picked up the cheapest one I could find on ebay (hence 14.5 PA/DP20) and it came out to $100 for one!

Yes, quite a few of them...I searched on gear cutter 20DP. For a set of 8, $65 plus $5 shipping. So I was inaccurate.

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