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japcas
02-05-2011, 03:41 PM
Any of you guys ever buy anything from Hemingway Kits?
http://www.hemingwaykits.com/index.html

They have some neat stuff on their website. I am interested in the speed increaser for cnc engraving work. Any of you guys build one? It would be a neat tool to have and make a good project to build also. Any thoughts on how they are to deal with would be appreciated.

Here is a link to the speed increaser.
http://www.hemingwaykits.com/acatalog/Speed_Increaser.html

TGTool
02-05-2011, 05:11 PM
I like the idea of one and this design was in Model Engineers' Workshop a few years ago. John Stevenson commented on what he thought were deficiencies in the design on this forum so you might hunt that down for input. That's not a comment on Hemingway, but just the design. Also don't overlook that it reverses direction so you need to have a reversing motor or left hand cutters.

So far as I know Hemingway itself is a perfectly fine organization. It changed hands a few years ago and the current owner has expanded the offerings quite a bit which I think speaks well for his attention to the business.

squirrel
02-05-2011, 05:13 PM
The engine kits look really nice! please post on the quality if you do buy it because I might order one of their engine kits if its good stuff.

Bill Pace
02-05-2011, 05:43 PM
I cant comment on a kit, but I did just last week have dealings with Kirk Burwell there. I was interested in the "Spherical Turning Tool" kit but when I figured up the price delivered here to the states, it was rather shocking:eek: - $142

After stewing on it a few days, and still wanting to build the tool, I contacted Kirk about just furnishing the plans since I felt sure I had all the materials in the scrap box. He quickly responded back, saying that would be no problem, and explaining how to run it through my paypal account to specify just the plans only. I did this Thurs/27Jan rather late in the day, and 4 days later on Tues Feb2, I received the plans - now, this is from Britain! And, the plans are very nice too...

Ended up being something around $22. Very satisfactory transaction.

willmac
02-05-2011, 06:14 PM
I have built a few of the Hemmingway kits and have been very satisfied. Can post pictures if that would help you decide. The designs have mostly been redrawn recently and the drawings are good.

Kirk Burwell is a good guy to deal with.

John Stevenson
02-05-2011, 06:29 PM
The original design is flawed, nothing to do with Hemingway, they only sell the design on.

It's in MEW101 but not very clearly written, for a start the details of the sun wheel is not shown on the drawing and the parts when added up in length are longer then the length of the spindle.

Basically what Dick Stevens, the author does is use this epicyclic setup in what is know as Star driven where the planet carrier is fixed and the ring gear is driver with the sun as driven which gives 3:1 step up but in oposite directions.

He relies on one bearing at the base of the spindle, the top is unsupported and he's only using one planet gear so the effect is for the planet gear to push the sun out of mesh and so cause the spindle to wobble.

One standard off the shelf ball race cannot support a spindle on it's own.

http://www.stevenson-engineers.co.uk/files/speed%20increaser.jpg

This is a quick sketch of the original design.

Now and here's a job to design your own. If you use the Planetary setup where you hold the ring and drive the planet carrier the sun wheel will rotate in the same direction at a ratio of 4:1 step up.

Plenty of room to get additional bearings in and two planets to split the load and thrusts.

http://www.stevenson-engineers.co.uk/files/speed%20head2.jpg

Just a drawing as a design layout, you will need to design it round whatever gears are available. the original design called for 60 ring gear and 20 for sun and planet.

ammcoman2
02-05-2011, 06:42 PM
I have purchased four items from them over the years and have been very pleased with the service. I have always bought the plans without the material kits but have usually got them to send the "difficult to buy here" items. Examples are worm and wheel for the 4" rotary table, bearings for the Myford tailstock side leadscrew kit, etc. They can be obtained in North America but I find it easier to just get them to send the items.

Kirk, and before him, Neil have always resonded quickly with a price. I can recommend the company very highly.

Geoff

jugs
02-05-2011, 07:34 PM
Neat design sir john

Love the pretty colours man http://www.freesmileys.org/smileys/smiley-greet001.gif (http://www.freesmileys.org/smileys.php)

john
:)

steverice
02-05-2011, 08:12 PM
I like the idea of the tool post grinder, has anybody built that one yet?

japcas
02-05-2011, 09:08 PM
Thanks for the info everybody. Especially John for the heads up on the design flaws of the speed multiplier. I wouldn't mind to spend the money on the kit if it worked properly but I don't like the idea of one bearing supporting the spindle. Maybe when I get around to needing one I'll just design one myself. Thanks again.

uncle pete
02-05-2011, 10:50 PM
+1 for Kirk being a great guy. Have talked with him on the phone a few times.

Pete

Zahnrad Kopf
02-09-2011, 08:06 PM
Now and here's a job to design your own. If you use the Planetary setup where you hold the ring and drive the planet carrier the sun wheel will rotate in the same direction at a ratio of 4:1 step up.

http://www.stevenson-engineers.co.uk/files/speed%20head2.jpg

Just a drawing as a design layout, you will need to design it round whatever gears are available. the original design called for 60 ring gear and 20 for sun and planet.

This is very similar to one I'm working on myself, John. I had to make some small planetaries, so I made a couple extras while I was at it, with the intention of using one for this project.

Something to think about for others is the use of multiple stages. I've got two different ones I'm working with, but both are three stage. One of them gives me a 216:1 ratio. Still gotta settle on bearing choices for the spindle, though...

John Stevenson
02-10-2011, 04:26 AM
Yes funnily enough I was pricing some gears up today, decided to increase them from 0,5 mod [ 48 DP ] that were in the original design to 0.8 mod [ 32 DP ] for strength, this using off the shelf gears.

I was going to use one of these for the spindle.

http://homepage.ntlworld.com/stevenson.engineers/lsteve/files/ER11-Collet-Chuck.jpg

Off the shelf ER11 spindle, this is the old design the new ones have a smaller nut.
The OD is a tad under 16mm but 16mm bearing are hard to get so I was going to sleeve off the shelf 17mm bearings.
The end you can't see has a JT1 taper so anything can be fitted to it to carry the sun and lock nuts etc.

Zahnrad Kopf
02-10-2011, 07:21 AM
Yes funnily enough I was pricing some gears up today, decided to increase them from 0,5 mod [ 48 DP ] that were in the original design to 0.8 mod [ 32 DP ] for strength, this using off the shelf gears.

Heh, that's funny... The gears I made for the two palnetaries are .7Mod and .8Mod. :) They get used in power tools that see torque and abuse, so I know they'll be good for driving small end mills.


I was going to use one of these for the spindle.

http://homepage.ntlworld.com/stevenson.engineers/lsteve/files/ER11-Collet-Chuck.jpg

Off the shelf ER11 spindle, this is the old design the new ones have a smaller nut. The OD is a tad under 16mm but 16mm bearing are hard to get so I was going to sleeve off the shelf 17mm bearings. The end you can't see has a JT1 taper so anything can be fitted to it to carry the sun and lock nuts etc.

Hey, that's kinda nice... might crib that from you... Have you given any thought to floating the sun? That's my plan. Leave the sun floating and utilize driving features.

Your Old Dog
02-10-2011, 08:29 AM
I'll play the straight guy.

What's a Hemingway?

japcas
02-10-2011, 08:53 AM
I'll play the straight guy.

What's a Hemingway?

Follow the link in the first post, that is the name of the website. They sell all kinds of plans and kits to build tools and model engines, a very neat website.

Rustybolt
02-10-2011, 09:21 AM
I'll play the straight guy.

What's a Hemingway?



American author of ripping yarns.Liked to fish and hunt. Committed suicide.The end.

macona
02-10-2011, 01:19 PM
You might keep an eye out on ebay for the Nikken spindle speeders. They are basically the same thing and seems to sell around $300 used. I doubt you can get all the gear and bearings to build one with this.

Spindle speeders do get hot. Often considered making a wrap around cooling manifold to cool it for long runs.

djc
02-10-2011, 01:33 PM
I was going to use one of these for the spindle.

http://homepage.ntlworld.com/stevenson.engineers/lsteve/files/ER11-Collet-Chuck.jpg



Would an ER11 extension chuck as sold by CTC be an alternative economical starting point? They come in 150mm long and 16mm or 20mm dia. Grind the 20mm one down to 17mm.

John Stevenson
02-10-2011, 02:10 PM
You might keep an eye out on ebay for the Nikken spindle speeders. They are basically the same thing and seems to sell around $300 used. I doubt you can get all the gear and bearings to build one with this.

.

Just done a quick search Ebay US and Ebay UK, plenty of Cat50 shanks and over a foot long, one in the US on a plain 3/4" shank but not really suitable for a small mill.

What is lacking is a small head suitable for engraving on the CNC X series mill conversions that are limited by the low top speed of usually 2,000 rpm.

Cost wise I have costed the ring gear and 3 pinions off the shelf in the UK for 42.59, bearings will cost another 10, that bought in spindle is 15 extra

It's not about saving money it's about getting what isn't commercially available.