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View Full Version : Making a right-angle attachment for mill?



KiddZimaHater
01-27-2009, 11:56 PM
Has anyone tried to make a right-angle attachment for their knee mill?
Like this style:
http://i7.ebayimg.com/08/i/001/27/9b/e4c7_1.JPG
I'd like to have one, but the price is scary, and FINDING one for my Millrite isn't easy.
How hard could it be? :eek:
That's a trick question.......
Here's a starting idea.
Kinda build around these miter gears?
These gears can be found cheap.
Box them in, add bearings. Reverse engineer?
http://www.electricscooterparts.com/ebaypics/smt-1020cb.jpg
Yes? No?
Am I outta my mind?
Has anyone tackled this before?
I need your 2 cents.

tattoomike68
01-28-2009, 12:57 AM
Anything is possible, how bad do you need it and do you have the work for it to justify it?

Its an ambitious project but totaly doable. if you are good at farmerizing and afro-american engineering you could whip one out in a few hours.

Horizontal mills are out there to be found, I would key miles of shaft with one, its a gravy job.

oldtiffie
01-28-2009, 02:27 AM
Why not think about the spider gears in a car differential? Or the crown-wheel and pinion? A lot of the work may be done. A bit of creative thinking is all that is required. It is only limited by your resources, determination and skills.

Sure, you may have to make compromises.

Other recent threads have mentioned BP mills that there was no buyer for and went to scrap. There would be a fair chance that there would be tools etc. with them - perhaps a right-angle drive - or the makings of one.

macona
01-28-2009, 03:51 AM
The spindle bearings in the right angle attach are just like the main spindle. High grade angular contact bearings. You will end up spending as much on bearings as you can pick up an old used Bridgeport right angle attach. The things hardly got used so they are rarely worn out. I think the one I sold on ebay sold for less than $300.

SGW
01-28-2009, 07:55 AM
I've certainly thought about it, never to the point of actually starting construction.

What sort of spindle do you want in the attachment? Do you want it to take R8 (or other) collets? If so, that implies a good-size hole through the middle of the gear.

There is also the problem, as noted, of suitable bearings. I've thought that maybe Timkin roller bearings, as in car wheel bearings, might work. Since I'd anticipate using the right-angle attachment mainly for slitting saws and drilling, I think slightly less than high-precision bearings might be acceptable.

jimmstruk
01-28-2009, 09:42 AM
Keep a watch in Enco hot deals monthly flyer, they often have an angle head kit on sale that includes the angle head, a horizontal arbor and the arbor support and all the running bushings for under $400. JIM

lazlo
01-28-2009, 11:08 AM
The spindle bearings in the right angle attach are just like the main spindle. High grade angular contact bearings. You will end up spending as much on bearings as you can pick up an old used Bridgeport right angle attach.

I have a Bridgeport-brand right-angle attachment, and not only does it use precision bearings, but it also uses spiral bevel gears to minimize gear noise in the the finish.

I'm sure you could make a functioning right-angle attachment with a pair of common crown gears and plain bearings, but you'll still need a mass of cast iron or steel pipe for the housing. I know this board is all about build over buy, but that's a big project for something that sells for $200 - $400 on Ebay...


I'd like to have one, but the price is scary, and FINDING one for my Millrite isn't easy.

Why don't you just buy one of the Bridgeport right-angle attachments on Ebay, and make a quill adapter? Is your Millrite R8?

TGTool
01-28-2009, 11:20 AM
If I remember correctly one of the Village Press project and tip books has a design and drawings for one. Two intersecting tubes and miter gears. It they've got table of contents you may find it, or I may find my copy first.

Lew Hartswick
01-28-2009, 12:37 PM
I have a Bridgeport-brand right-angle attachment, and not only does it use precision bearings, but it also uses spiral bevel gears to minimize gear noise in the the finish.
I was going to suggest the same. The compound miter saw (wood)
that I have had apart used the spiral bevel gears.
We have about 3 or 4 of the Bridgeport right angle drives at school
and I don't think they have ever ben on a machine. I "almost" put
one on once to use a slitting saw but found a way to do the job
without. :-)
...lew...

pcarpenter
01-28-2009, 02:44 PM
The project transcends the comparitively simple building of the gearbox since to use a traditional arbor, you will need the long arbor (expensive but could be made) and the support for the other end of the arbor. This is an item that would seem very simple since it's just got a dovetail cut in it and it clamps to the dovetail way on the bottom of the ram. On the other hand, it probably needs to be very precisely scraped to fit since you couldn't have much angle to the arbor over say 8-10 inches before it would cause an issue. Your cutters would not run square and you would most certainly eat the support bearing. There might be some way to Rube Goldberg the making of the hole in the arbor support by using the angle attachment to insure alignment.

If you wanted the head just to use with cutters in a collet, this is a non-issue. I would be tempted to consider a planetary gear arrangement if possible in the confined space. As such, there could be a gear reduction as most horizontal milling cutters will need to run at the low end of the Bridgeport's normal range...especially as they get larger in diameter.

I scrounged an old horizontal mill. If you have the shop room, this may be about as cheap as the attachment on the BP....and a lot more capable.

Paul