How Would You Make This Cutter

[GeneT45]

Yes, the cutter can be purchased from the competing manufacturer, but the cost uses up all the profit. If I have a $2000 Bridgeport sitting in the middle of the shop floor, would like for it to earn something.

You can make anything with a manual machine - except money... (a slight exaggeration, but there's a point there...)

GsT

 

[extropic]

How much does the commercial item sell for?

Do you know what material it's made of? Is it hardened? How hard?

What material spec do you intend to use?

The lathe work is a no-brainer. However, cutting all those teeth using a manual indexer (in lots of more than one or two) sounds mind-numbingly slow and tedious to me. Any chance you could come up with an electronically controlled indexer?

Are you a very good TIG welder?

 

[extropic]

A little more thinking resulted in the following:

Wouldn't it be nice if the cutting edge(s) could be refreshed without making the whole piece again.
Because I don't know the nature of the "sampling" procedure, and I dislike guessing what the important factors might be, I'm asking you to describe the process and criteria a sample is judged by.

If you think the tool MUST be exactly like the one pictured, no point in pursuing alternative design options.

 

[Weldingrod1]

I like the idea of straight knurling to get those teeth. Doing it on an angle will add a bit of challenge, but waaaay faster than indexing.
Leaving the ID undersized for the knurl is a good choice. An expanding mandrel inside would give you further support and make swapping faster.

 

[Janderso]

Does nobody make/sell these commercially?

Boy, no kidding

 

[CJ5Dave]

They can be resharpened /refreshed with a file. I have 4. If I sell the products I will be out of business really soon. The part coats about $75 as I recall, but I am retired and need some mill projects to learn on. The whole sampler sells for $250 to $300, but parts are frequently backordered. No I can't tig. I imagine the cutter is tempered. Not sure what material I would use, would use mild steel I have on hand for prototypes. An electronic controlled indexer I am sure is out of my price range. The part does not have to be identical to that, other sources make them with a lot less flutes, although they don't cut as well. My main question is can this be done with an indexing table, and if so what cutter to make the teeth. I think I can handle the lathe end.

 

[woodchucker]

So I would use o1 and cut it, then harden it.
https://www.mcmaster.com/products/bevel-milling-cutters/cut-style~double-chamfering/ you can get larger cutters to mount on arbors, but these can get you there.

 

[CJ5Dave]

Thank you Woodchucker for the tool recommendation. Answered my question well.
Here is a similar sampler:

Forage Probes and Probe Parts | Dairy One

dairyone.com

I make the drill arbors, but theirs attach with a detent ball and are aluminum. Mine have a thru pin, easier to remove, and are steel. I use conduit tubing as I can't seem to source the stainless tubing. You chuck the adapter in a drill, push the sampler spinning onto a bale of hay, it cuts a core sample of hay and retains it in the tube. After 4 or 5 thrusts you remove the drill adapter and push the hay into a ziploc with the wood dowel. You ship the hay sample to a lab and they analyze if for nutrition, toxins, mold, whatever parameter is needed for the livestock nutrition or health. Penn State developed this probably 70 years ago, Colorado State has a similar, many more people have other versions. It shreds the hay into short pieces as well so the lab can process it easier. Most labs won't take a grab sample of hay anymore.

 

[CJ5Dave]

Here is an aftermaket tip, cut differently, have used this one, does not cut as well:

1" Serrated Replaceable Tip

Serrated Soil Probe Replaceable Tip, Soil Probe Replaceable Tip, Serrated Replaceable Tip, Serrated Tip, Replaceable Tip

www.ams-samplers.com

 

[brino]

If I was only making one or two for myself and only needed them functional and not beautiful I'd have a try with a blank and an angle grinder.
Put the part on one of the tubes, hold that in a vise and index manually.
With a bit of practice and patience I'd think they could be made well enough.
Control your tooth gap with the disc thickness and good grinder control.

However if:
1) I was retired (so learning time outweighs the cost of whatever else I should be doing), and
2) I just bought a mill and was looking for projects to learn with, and
3) had a few bucks to spend on a rotary table(which will find more projects in the future), and
4) I was considering making a few for sale and wanted them to be pretty

.....then I would rough out the blanks on the lathe (turn, taper, drill/bore) then move them to the mill.
Hold the cutter in the vertical head, using the rotary table on the mill table to position the tapered side for tooth cutting

The set-up would be much like the ones in the recent press rebuild here:
https://www.hobby-machinist.com/attachments/110-jpg.490796/
https://www.hobby-machinist.com/attachments/111-jpg.490797/

if that direct link to the pictures doesn't work, then it's pictures 9 and 10 in this thread:
https://www.hobby-machinist.com/threads/manley-40-ton-press-rescue.112418/post-1132982

......but with the rotary table set as whatever oblique angle roughly matches the taper on the part.

Heck with spare time a person could even experiment with tooth count, angle and depth to find the best combination.

Have Fun!
Brian