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Pete F
01-06-2010, 01:30 AM
...so please be gentle. I'm toying with the idea trying my hand at cutting gears with an involute gear cutter like this (http://www1.mscdirect.com/CGI/NNSRIT?PARTPG=IMLMKD&PMPXNO=1711355). I won't necessarily be getting one with that pitch or number, but it is an example of the type. What I can't seem to determine is what kind of arbor I need to hold it in my mill, which takes an R-8 taper. Is it such common knowledge that it expected to be obvious? I kind of expected to find something like a general purpose 7/8" diameter R-8 arbor with a standard keyway, but I can't. Is there something I can get that can also hold other tooling, like slitting saws?

Feeling dense. Am I even using the right terminology?

Help?

-Pete

oldtiffie
01-06-2010, 01:46 AM
This is what you are after - except that this is an MT3 x 25.4mm (1.000")whereas you want R8 x 7/8" (0.875"). These are from OZ but they will be available to suit your R8 x 7/8" requirement in the USA.

https://www.machineryhouse.com.au/Products?stockCode=M538

Here is my 1" (25.4mm) x MT3 stub arbor assembled - you need the 7/8" x R8 equivalent:

http://i200.photobucket.com/albums/aa294/oldtiffie/HF-45%20Mill%20misc/Stub_arbor1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/HF-45%20Mill%20misc/Stub_arbor2.jpg

All stub arbors will - or should have - a tapped hole for a draw-bar in your mill spindle.

Machinist-Guide
01-06-2010, 03:23 AM
Yes you can get this type arbor as a R8
Check with MSC

Machinist-Guide
01-06-2010, 03:34 AM
I checked MSC all I found is set of 5 different types. I am posting a link to them to give you an idea of what to look for. You need the one on the left in the photo.

http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=1783782&PMT4NO=0

pipeclay
01-06-2010, 03:46 AM
Would suggest to know what DP you are going to use as the Bore sizes will differ.
I cut quite a few 16,18 and 20 DP gears ,using a M/T3 arbor/arbors I just make them to suit my needs.
Another thing to consider if you by Arbors allready made is the length of the Arbor,in my case I have to change Arbor lengths when I cut 100,120 and 127 tooth gears.

Bguns
01-06-2010, 03:50 AM
If a low speed/quality gear is needed..

A simple flycutter ground to same shape as a involute gear cutter will work fine.

Hold it in a simple boring bar..

Splines can be done the same way...

Slow due to only one cutter tooth, but will get job done for change gears and such...

Black_Moons
01-06-2010, 04:02 AM
Yea as some have stated, don't underestimate the arbor length you will need to clear your gear and/or rotary table.

form_change
01-06-2010, 05:41 AM
Just to clarify here - have you a horizontal spindle machine or a vertical spindle machine? Arbors as discussed are good for horizontal machines, but if you have a vertical spinlde machine you may be better with something like a slitting saw cutter. A random search threw up this link. This is for MT3, but you get the idea.
http://www.rulezman.com/rulezman_workshop_2/slitting_saw_arbor.html

oldtiffie
01-06-2010, 06:38 AM
...so please be gentle. I'm toying with the idea trying my hand at cutting gears with an involute gear cutter like this (http://www1.mscdirect.com/CGI/NNSRIT?PARTPG=IMLMKD&PMPXNO=1711355). I won't necessarily be getting one with that pitch or number, but it is an example of the type. What I can't seem to determine is what kind of arbor I need to hold it in my mill, which takes an R-8 taper. Is it such common knowledge that it expected to be obvious? I kind of expected to find something like a general purpose 7/8" diameter R-8 arbor with a standard keyway, but I can't. Is there something I can get that can also hold other tooling, like slitting saws?

Feeling dense. Am I even using the right terminology?

Help?

-Pete

Pete.

Here is a link to one of my suppliers in Australia (OZ) re. gears cutters over a wide variety of DP's, pressure angles, numbers of teeth etc. They are in sets of 10. Both DP (inch/US) and Module (metric) series are covered.

Note that all have a 1" bore (25.4mm here as we are metric in OZ).

My guess is that your mill is a vertical mill.

http://mcjing.com.au/categorybrowser.aspx?categoryid=1130

The conversion rate is AU$1 ~ US$0.90 or US$1 ~ AU$1.10

I will be very surprised if the same items are not available in the USA.

John Stevenson
01-06-2010, 09:05 AM
Make one and make a support while you are at it to keep it rigid.

http://www.stevenson-engineers.co.uk/files/vertical%20support.jpg

Not my machine and I'd like to give credit on this to whoever made it but I don't have that information.

If I was making one I'd use a dovetail packing piece and an off the shelf self aligning plummer block.

.

Carld
01-06-2010, 09:32 AM
Pete, you can get R8 mandrels in 3/4", 7/8" and 1" and maybe bigger. I have a Straight shank 3/4", a 7/8" R8 and a 1" R8 and have recently used all of them. I just bought the 1" R8 from CDCO and it is just fine. I made some spacers for all of them also.

If your going to cut gears then get the diameter mandrel to fit the gear cutter you choose and use it with your index head and cut your gears. The turret head mills will do a good job cutting gears. You don't have to use a horizontal mill.

Pete F
01-06-2010, 11:43 AM
OK, I think I get it. I found several sources for 1" R8 stub arbors, but I haven't had much luck with 7/8". The size gears I want to make seem to have cutters with smaller bores, but I did find a straight shank 7/8" arbor (http://www.shars.com/products/view/877/34x78quot_Stub_Milling_Machine_Arbor). I need to do some figuring and measuring, checking clearances and all that, but hypothetically speaking, would the above mentioned arbor, along with a 3/4" R8 collet work to hold this gear cutter (http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=1711369&PMT4NO=77220031)?

Full disclosure here, I have an X2 mill from Harbor Freight, a rotary table with a chuck and an indexing plate. I do not have a lathe, although I have done some turning with the mill, but it seems to stress the machine in ways it wasn't really built for, so I'm probably not going to want to turn anything tougher than aluminum on it again. I want to make small gears for motors in small robots. If I am heading down a path of frustration, tell me now! :)

-Pete

recoilless
01-06-2010, 01:39 PM
If you go w/ the stub arbor, set it up in your mill and check the run out. I bought one from Travers a couple years past, the kind w/ 1.25" and 1" shoulders to handle both size cutters. I have only 1" holed gear cutters. The 1.25" was OK but the 1" portion had .008 run out. How they managed that, I don't know as you'd think the work was done in the same setup. No burrs, just out. Checked it in a v-block after, same thing. Wears your cutter out unevenly.

ahidley
01-07-2010, 06:35 PM
This is a setup like you'll need. It even uses cutters purchased from MSC just like you need.
http://i194.photobucket.com/albums/z80/ahidley/5CuttingGearTeeth1.jpg

http://i194.photobucket.com/albums/z80/ahidley/5CuttingGearTeeth1.jpg

You'll end up with a stacklike this after parting them offf and boreing or reaming the hole
http://i194.photobucket.com/albums/z80/ahidley/2CutGears1.jpg
http://i194.photobucket.com/albums/z80/ahidley/2CutGears1.jpg

sansbury
01-07-2010, 07:13 PM
I want to make small gears for motors in small robots.

If your gears only need to mesh with themselves, you can make a straight hob (OK, you might want a real lathe for that) pretty easily, or even a spiral hob, either of which can make gears of any tooth count. This website shows a little of the process. Smartflix also has a Jose Rodriguez video you can rent for $10 that is exhaustive to the point of ridiculous but doesn't leave any detail out.

http://jzcomputer.com/spurgears/index.aspx

Carld
01-07-2010, 08:15 PM
This is disgusting, I searched several sites and didn't find an R8 x 7/8" stub arbor. I know someone made or makes them because I have one.

I wouldn't be afraid to use the straight shank in a collet or endmill holder though. I have a straight shank arbor for 3/4" bore cutters and it works fine in a collet in my mill.

Pete F
01-07-2010, 09:55 PM
If your gears only need to mesh with themselves, you can make a straight hob (OK, you might want a real lathe for that) pretty easily, or even a spiral hob, either of which can make gears of any tooth count. This website shows a little of the process. Smartflix also has a Jose Rodriguez video you can rent for $10 that is exhaustive to the point of ridiculous but doesn't leave any detail out.

That was my original plan, but I decided (against my normal, usually wrong, instincts) that it was a tad ambitious given my equipment and experience. If I already had the proper equipment, I'd give it a go, since drill rod is cheap. However, since I'm designing all the parts, I can live with a pretty small selection of tooth counts, and gear cutters aren't that expensive if you only need two of them to start.

-Pete

Pete F
01-07-2010, 09:59 PM
This is disgusting, I searched several sites and didn't find an R8 x 7/8" stub arbor. I know someone made or makes them because I have one.

I wouldn't be afraid to use the straight shank in a collet or endmill holder though. I have a straight shank arbor for 3/4" bore cutters and it works fine in a collet in my mill.

That's why I was surprised. I've gone ahead and ordered my cutters, although I have not ordered the arbor yet, but am planning on just getting the straight shank, since I already have a 3/4" collet.

Thanks, for all the advice. I feel pretty confident there will be gears in my not-to-distant future.

-Pete

J Tiers
01-07-2010, 10:33 PM
This is disgusting, I searched several sites and didn't find an R8 x 7/8" stub arbor. I know someone made or makes them because I have one.

I wouldn't be afraid to use the straight shank in a collet or endmill holder though. I have a straight shank arbor for 3/4" bore cutters and it works fine in a collet in my mill.

or a person can make an arbor........ might be quicker, sure to be cheaper.

gwilson
01-07-2010, 10:46 PM
A single cutter won't cut but a certain range of gears. You will need a bunch of gear cutters to cut gears of differing diameters,even if they are all of the same pitch.

If you are good with files,and have several sample gears to go by,you could get some 1/4" square tool steel,and carefully file out cutters corresponding to the different gear diameters you have.

Carld
01-07-2010, 11:48 PM
I got the R8 x 1" stub arbor from CDCO last week for $39 I think, maybe $29. Anyway It runs true and is ground finished. Even a straight shank is cheaper than I can make it considering the time and material. Especially if I need it now and I had a job for it when it arrived the next day.

J Tiers
01-08-2010, 12:07 AM
If you CAN buy it, and particularly for that cheap, you'd be crazy, or stubborn as heck, to make it.

Everyone was saying that they couldn't find them, in which case making is reasonable. Same if they are available but just stupid expensive.

I have made MT2 and MT3 shell mill arbors because the only one that ever had them was that Lathemaster guy in Texas. He apparently only sold in sets, most of which I didn't want, only sold on ebay store (I don't do ebay), didn't have any of the sets in stock, and he was bad about answering email inquiries. Aside from that he was a great source....... so I made them.

Carld
01-08-2010, 09:57 AM
Pete, if your cutters have a 7/8" bore then buy an R8 x 1" stub mandrel and turn it down between centers to 7/8", thread it and cut the keyway and make a new nut.

It would be easier to do that than make the R8 adapter area.

I just don't understand why they are not available anymore in 3/4" and 7/8" when there still are cutters with those hole sizes.

John Stevenson
01-08-2010, 11:13 AM
Smartflix also has a Jose Rodriguez video you can rent for $10 that is exhaustive to the point of ridiculous but doesn't leave any detail out.



Bollocks

That Rodriguez video is the pits, quality is that bad you can't see if they have been cut with an involute cutter, a straight sided cutter or an angle grinder.

One of the main details he leaves out is the correct formula for Pi.
He gets this wrong in every calculation and so every result is out.

Do a search on Youtube for a user called Hobbynut, this guy has about 7 or 8 video's on there showing correctly what Rodriguez is trying to show and there is no charge for it.

I don't mind paying to learn things but Rodreguez is ripping people off with his poor quality video's, bad information and his high tensile licorice machine he's attempting to cut gears on.

.

ahidley
01-10-2010, 07:32 PM
Search ebay.

Black_Moons
01-10-2010, 07:40 PM
Agreed. ebay often has lots of oddball cheap tooling.

I think KBCtools also has R8 stub arbors

I love that support on the dovetails.. mmm, the dovetails on my IH mill go down pertty low I bet I could make a similar setup.. Course, id need to remove the way cover temporarly. But the rigidity of support at both ends (especialy when you needed to have a long arbor to have clearance from the quill) is so much higher it could be worth it.

I LOVE the idea of making a long long gear and parting it off
for some reason I allways thought everything but the spiral hob methods to be insanely inefficent at making gears unless CNC.. Because I was thinking 1 gear at a time, but now that I see a dozen gears can be easily made at once, it definately seems worth it.

pipeclay
01-10-2010, 08:54 PM
Just be aware that the Vertical arbor support may be limited by the Diameter of the gears being cut or depth of the table.

dp
01-11-2010, 12:56 AM
Make one and make a support while you are at it to keep it rigid.

Not my machine and I'd like to give credit on this to whoever made it but I don't have that information.

If I was making one I'd use a dovetail packing piece and an off the shelf self aligning plummer block.

.

I like that so much I'm going to make one for my machine. It deserves an HSM part number.