• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.
  • Guest,  We want to wish You and Your Family a Healthy, Happy Thanksgiving! Click the "X" at the top right corner to remove this notice)
  • PLEASE: Read the FORUM RULES BEFORE registering!

4

Camjack Knurler

3
Like what you see?
Click here to donate to this forum and upgrade your account!
10

Hawkeye

Active User
H-M Supporter-Premium Member
Joined
Jun 17, 2011
Messages
1,769
Likes
399
#1
Okay, guys. A couple of months ago, I mentioned a Project-in-Waiting that I called a Camjack Knurler. When you invent something, you're allowed to make up words, too. It came about because I had checked out several sites on clamp knurlers. Most seem to use a 6 mm threaded shaft to apply pressure, but some commented that it didn't have enough force for steel. This tool has plenty of pressure, easily controlled.

Members of this forum may use this principle to build their own, but, of course, may not profit from my design.

Here's a look at the finished product in use, mounted in the QCTP. The bar on the top with the 1/4" jack screw is the camjack. When the tail is raised with the jack screw, the camjack pivots around the opposite end and pulls up on the 1/2"-20 main screw. It provides more than 5 to 1 mechanical advantage. The knurl arms are pivoted farther away from the roller ends than normal. This unit is designed for up to 2" knurled work.
PA160049.jpg

Jumping back to some of the construction details. The bottom bar and the camjack are clamped in the vise with a piece of 3/8" aluminum between them to plunge-mill the depressions for the 3/4" main screw pivot blocks.
PA150039.jpg

PA150041.jpg

The axles for the knurls were turned from a pair of 5/16" grade 8 bolts.
PA150043.jpg

The complete tool is set up for the test cut. The 1/2"-20 main screw works well with a lug nut as the adjusted. This is turned hand-tight once the crossfeed is centered on the work, with the camjack all the way down. Then the jackscrew is tightened with the work oiled and the lathe running at knurling speed. Enough pressure can be applied by hand that I may just add a knurled top on the jackscrew.
PA160046.jpg

I'm quite pleased with the way it works. This will, of course, be the main screw nut. It has to have a knurled one, doesn't it? (See the top photo.)
PA160047.jpg

PA160049.jpg PA150039.jpg PA150041.jpg PA150043.jpg PA160046.jpg PA160047.jpg
 

hq308

Active User
Active Member
Joined
Jul 18, 2011
Messages
224
Likes
0
#2
Nice job Mike.:cool:

I especially love the wheel nut you used temporarily on the main screw.:D
 

Highpower

Active Member
Active Member
Joined
Mar 22, 2011
Messages
450
Likes
3
#3
Mike, that is one heavy duty knurler! I know that puppy applies some serious pressure to those rollers, because I have a different tool that uses that principle for separating the taper on ball joints. When they let go, they do it with a BANG!

Great job, and great idea. Well done Sir!

View attachment 667
 

Hawkeye

Active User
H-M Supporter-Premium Member
Joined
Jun 17, 2011
Messages
1,769
Likes
399
#4
Sorry, Mayhem. No plans. Just a basic CAD sketch to work out a few ideas. Funny thing was, I zoomed in on the layout I wanted and printed Display onto an 8 1/2 x 11 sheet. When I laid the L-shaped mounting arm on it, it fit exactly. All I had to do from there was measure off the drawing. Nice when a 'plan' comes together.

For reference, the arms are 1" x 5/8" bar stock 5" long. Material is MU (Magnetic Unknownium - not to be confused with the nastier Ferrous Unknownium). The knurls were taken from my cheapy bump knurler.
 

joesmith

Active User
Active Member
Joined
Aug 23, 2011
Messages
89
Likes
2
#5
Congrats

Nice design and execution. I intend to copy it. I have worn out the bump knurlers that came with my toolpost sets, The knurls don't like stainless.
Joe
 

Hawkeye

Active User
H-M Supporter-Premium Member
Joined
Jun 17, 2011
Messages
1,769
Likes
399
#6
Okay, Mayhem, here's the individual pieces of the knurler. It's a bit more work to post without the buttons, but I'll try.

All of the pieces are shown. I did try a spring on the main threaded shaft, but it kept getting jammed up in the slots, even with washers in place.
PA210002.jpg

The threaded parts. The jackscrew is not shown in this one. The main shaft is 1/2 - 20. It's swivel is threaded and held in place with strong threadlocker. A smaller shaft diameter would likely work, but I wouldn't go any smaller than 3/8". Fine thread is recommended.
PA210003.jpg

The mounting arm was the first part made, some time ago. Most clamp knurlers are completely on the work side of the toolpost. I figured longer arms pivoted from behind the post would give better control.
PA210009.jpg

The arms are 5" long. The bottom one has a 3/4" diameter swivel groove. Both have 1/2" slots to allow the main shaft to swing to suit diameters of work up to 2". The upper arm has a 3/16" diameter slot for the camjack fulcrum.
PA210004.jpg

The key to the power of this knurler is the camjack. The fulcrum is a piece of 3/16" music wire welded into a milled slot at the end. The end of the jackscrew is rounded to allow it to move on the flat surface of the upper arm.
PA210005.jpg

Final parts include the knurled (of course) main shaft nut, diamond knurls and the upper shaft swivel.
PA210010.jpg

Have fun making your own version of this tool. I'm very pleased with the way it works.

PA210002.jpg PA210003.jpg PA210004.jpg PA210005.jpg PA210009.jpg PA210010.jpg
 

Splat

Active User
H-M Supporter-Premium Member
Joined
Mar 10, 2012
Messages
1,026
Likes
115
#7
Mike/Hawkeye(MASH, in my top 3 tv faves! :)) thanks for posting this! Once I get my lathe I need to do some serious knurling so I'm going to try to build this. It's a Franken-knurler! :)
 

bcall2043

Active User
Active Member
Joined
Oct 6, 2010
Messages
697
Likes
27
#8
Okay, guys. A couple of months ago, I mentioned a Project-in-Waiting that I called a Camjack Knurler. When you invent something, you're allowed to make up words, too. It came about because I had checked out several sites on clamp knurlers. Most seem to use a 6 mm threaded shaft to apply pressure, but some commented that it didn't have enough force for steel. This tool has plenty of pressure, easily controlled.

Members of this forum may use this principle to build their own, but, of course, may not profit from my design.
Hawkeye,

Thanks for the design. It's a great idea. I put it on my list of want-to-builds. I don't know how I missed it when first posted.

Benny
 

swatson144

Global Moderator
Staff member
Active Member
Joined
Apr 12, 2012
Messages
524
Likes
27
#9
Hawkeye and I discussed me releasing a set of drawings for this and he was gracious and generous enough to say go ahead with a few common sense exclusions !not for commercial use! Use at own risk.

I'm not quite ready to release the drawings yet. Things are moving a little slow in testing them since I had a hernia repaired and my gall bladder removed 2wks & 3 days ago. The doctor allows me to lift 15#s now but that still leaves me using the HF drill press vice. I just want to make sure that if someone orders material and the parts don't fit it's their own dang fault and not the drawings.

15# vice.JPG

It is so much like clamping work on the table with that vice.

deplanbossdeplan.JPG

Here's is what I have done so far sitting on full size drawings.

Steve

15# vice.JPG deplanbossdeplan.JPG
 

churchjw

Active User
Active Member
Joined
Oct 4, 2011
Messages
728
Likes
38
#10
Really nice job on this. I bought one of these a few years back. Big mistake I should have just made one. Maybe your post will inspire me to make a new one. I like your design better than the one I bought by miles.

Jeff
 

Hawkeye

Active User
H-M Supporter-Premium Member
Joined
Jun 17, 2011
Messages
1,769
Likes
399
#11
I'm looking forward to a few guys building their own. I'd like some feedback on how they work for you. I was impressed with the fact that I could force the knurls into the steel by turning the jack screw with my fingers.
 

swatson144

Global Moderator
Staff member
Active Member
Joined
Apr 12, 2012
Messages
524
Likes
27
#12
I got far enough along that I do not feel there are any insurmountable problems with the drawings. they are currently available here . As yet untested use at own risk etc. I will put it in the downloads section here on the forum when I have it in final form.

Hopefully my shoulder bolts will arrive today and I can finish it up and test it out and make updates to the drawings, finish the notes and post it. The 3/16" ball end cutter arrived. I probably should have just used bolts like Hawkeye (perhaps why he did?). Definitely should have procured the odds n ends before starting. It's just that I didn't consider them that odd to be NC, or NIS everywhere local.

It is sorta astounding what pieces one may need for a small project that can't be easily found locally in a city as industrial as this one. A lot of I can order it for you, or they come in a box of 25.

Steve
 
Last edited:

swatson144

Global Moderator
Staff member
Active Member
Joined
Apr 12, 2012
Messages
524
Likes
27
#13
It's finished. The first test didn't go so well but it is assuredly my fault as the tool behave perfectly. Actually it behaved as if it was 4X strength of what was needed to do the job.

testF.JPG

The knurling is not right but it is deep and there was no problem to the tool. I haven't much practice or experience at knurling as it just wasn't called for a lot in the navy. Most likely something stupid I'm doing. Frankly I just stuck it on the lathe to let the green loctite set up and then got carried away.

centerlineF.JPG

Seen from the centerline you can tell the tool is still a little high and the tool holder is bottomed out on the compound on my 12x36. when I get around to it I'll likely change the mount to be more of a sideways T than a sideways L.

Even though I'm only using an AXA and the 1/2" mount is plenty strong using a 5/8" plate will give enough clearance for the height adjusting wheel on the holder. 9/16" also. I shimmed it out .030" for clearance

I went with a 5/16" x 24 TPI on the cam (jack screw) simply because it looked more to scale with the other pieces.

I tend to make tooling and not spend a lot of time on the aesthetics. I never know when they will work as desired, and I figure once they prove to work well, I'll go back and make them pretty. Perhaps some day I will. So far not so much.

I'll update the plans and notes http://www.totallyscrewedmachineshop.com/projects/camjackknurler/camjack.html

Steve

testF.JPG centerlineF.JPG
 

ScrapMetal

Active User
Active Member
Joined
Apr 6, 2011
Messages
2,049
Likes
112
#14
I got far enough along that I do not feel there are any insurmountable problems with the drawings. they are currently availablehere. As yet untested use at own risk etc. I will put it in the downloads section here on the forum when I have it in final form.

Hopefully my shoulder bolts will arrive today and I can finish it up and test it out and make updates to the drawings, finish the notes and post it. The 3/16" ball end cutter arrived. I probably should have just used bolts like Hawkeye (perhaps why he did?). Definitely should have procured the odds n ends before starting. It's just that I didn't consider them that odd to be NC, or NIS everywhere local.

It is sorta astounding what pieces one may need for a small project that can't be easily found locally in a city as industrial as this one. A lot of I can order it for you, or they come in a box of 25.

Steve
Thanks to both of you for making the plans available. I've got too many things on my plate right now but I will surely make one of these in the near future as I really like the design.

-Ron
 

Hawkeye

Active User
H-M Supporter-Premium Member
Joined
Jun 17, 2011
Messages
1,769
Likes
399
#15
It doesn't matter what type of knurler you use. It still comes down to matching the work piece diameter to the pitch of the knurls. Get the diameter off and there's no way you will get a good finish. Get it off just the right amount and you will make a good fine pitch using a medium-pitch knurl set.

Steve, your camjack looks nice and solid. It should work very well for you.
 

swatson144

Global Moderator
Staff member
Active Member
Joined
Apr 12, 2012
Messages
524
Likes
27
#16
N = (pi ) (dia) (tpi)

N is the number of lines your knurl will make on the circumference of your part. TpI is the pitch of the knurl. In the unlikely event N is a whole number knurl away.

If N isn't whole say 14.4

diameter change = n (right of decimal .4) / (pi)(tpi)

Seems to be the common method.

There also seems to be thoughts that if it is slightly off a whole number the knurls will follow if set deeply and well lubed, probably about like mine did since I did no math, nor dust blowing or lube.

http://www1.mscdirect.com/CGI/NNPDFF?PMPAGE=1759&PMITEM=01295203&PMCTLG=00 and go to page 1752 for MSC's reference on knurling

Steve
 

November X-ray

Active User
Active Member
Joined
Jun 12, 2011
Messages
581
Likes
7
#17
Steve - I think you will get better results when you do use lube (or something) to flush the knurls clean with. I know with mine it makes noticable difference with flushing vs without!
 

swatson144

Global Moderator
Staff member
Active Member
Joined
Apr 12, 2012
Messages
524
Likes
27
#18
I finished my paying job so I got another run at it.

goodnufF.JPG

Turned out good enough for the 2nd try. Seems to need a little practice getting the tension right since you can put so much on it. seems to be nothing set in granite about this, just like playing music you just monkey around and practice, eventually the station will be in nice and clear.

Steve

goodnufF.JPG
 

Hawkeye

Active User
H-M Supporter-Premium Member
Joined
Jun 17, 2011
Messages
1,769
Likes
399
#19
If you're wondering about the pitch of your knurls, take one out of the holder and slip a shaft through it. Roll it in a straight line along a piece of paper on a flat surface. there will be enough oil on it to leave a print of the ridges. Next, draw a straight line along the path you printed, parallel with the direction of travel. Mark one knurl line where it crosses this line and another 1", 2", 5", 10" (or whatever) further down - longer is better, until you meet up with a clear intersection where knurl, horizontal line and inch mark come together. Count the knurl lines, not including the first one. Divide by the number of inches to get lines-per-inch.

If you divide 1 by the lines-per-inch number and record it, you can make up a table to keep in the shop with a number of workable diameters on it. Here's the chart I keep in the shop for my particular knurls. It will only work if yours have the same pitch as mine.
 

Attachments

jayman

Iron
Registered Member
Joined
Jun 17, 2014
Messages
7
Likes
0
#20
Nice job! Nice idea! Looks pretty cool! Have you tried it with straight knurls?
 

swatson144

Global Moderator
Staff member
Active Member
Joined
Apr 12, 2012
Messages
524
Likes
27
#21
No Sir I haven't. Truth be known I haven't had a need to knurl anything since, but the tool is there, the math is there and I am sure this will meet my knurling needs.

I speculate on pure conjecture that to do good straight knurls one would require knurls of the right pitch for the diameter of the work or vice versa. However to straight knurl to increase the diameter of a shaft to turn down to a bearing size would be simple. This tool would work well.

Steve
 

Hawkeye

Active User
H-M Supporter-Premium Member
Joined
Jun 17, 2011
Messages
1,769
Likes
399
#22
I haven't tried straight knurls either. Some day, I'll order a set and try them out.
 

jhamm

Iron
Registered Member
Joined
Oct 31, 2014
Messages
5
Likes
0
#23
I haven't tried straight knurls either. Some day, I'll order a set and try them out.
The Accu-Track website at http://accu-trak.com/holders_bump.html shows the following diagram, which says to use a single knurl die instead of a pair, when straight-knurling. Seems to me you could either not worry about it (ie go ahead and use two straight knurl dies in the scissors knurling holder) or use a plain (smooth) roller on one side. Or perhaps somehow synchronize the dies. Has anyone tried the holder for straight knurling? OR%20%28SELF%20CENTERING%29c_small.jpg
 

Attachments

Jim2

Active User
Active Member
Joined
May 5, 2014
Messages
73
Likes
23
#24
I've done a couple of straight knurls using two knurl wheels. It's worked fine the handful of times that I've done it, but I've only ever tried it in brass. I don't really do much knurling, so it could be just dumb luck!

Most recently did these 1/2" diameter nuts for my new knurler (no, not a camjack--sorry!).

IMG_4879_zpseb456833.jpg


Jim
 

Attachments

jhamm

Iron
Registered Member
Joined
Oct 31, 2014
Messages
5
Likes
0
#25
Most recently did these 1/2" diameter nuts [using 2 straight knurl wheels] for my new knurler (no, not a camjack--sorry!).
Jim
It looks like they turned out fine. BTW, did you invent that method of locking the axle pins in place, or was it on a set of plans? I assume the aluminum or steel bar stays down and in place during operation even if the brass nut loosens up. Have you noticed any other pros or cons to that pin-locking method?
 

Jim2

Active User
Active Member
Joined
May 5, 2014
Messages
73
Likes
23
#26
It looks like they turned out fine.
Yeah, I don't know as they'd look any better any other way.


BTW, did you invent that method of locking the axle pins in place, or was it on a set of plans?
Well, I'm not exactly sure! I know someone else had the idea of cutting the gash in the pin and tightening a small flat to hold it in place. I don't know as that person had an angle on the end, but it seemed like a good way to do it so that the flat would be easy to hold in place while tightening the knurl-nut.

I looked at a lot of knurlers before I made mine. I like to give credit where it is due, but I just can't remember where I saw it now.


I assume the aluminum or steel bar stays down and in place during operation even if the brass nut loosens up. Have you noticed any other pros or cons to that pin-locking method?
I haven't really used it much yet--just finished it a few weeks ago. The bars don't really seem inclined to move. It seems like a relatively simple, trouble-free way to hold the pins in place.

Jim
 

jhamm

Iron
Registered Member
Joined
Oct 31, 2014
Messages
5
Likes
0
#27
I've done a couple of straight knurls using two knurl wheels. It's worked fine the handful of times that I've done it, but I've only ever tried it in brass. [...]
Jim
I see that the question of straight knurling with a scissors clamp has come up before, in a August 2011 knurling thread, http://www.hobby-machinist.com/showthread.php/2637-Knurling-thread-by-George-Wilson?highlight=knurl. Some people tried using hard-rubber wheels in one side of the clamp. But at the end of the thread, George Wilson points out:
I cannot recommend trying to use any kind of rubber wheel in knurling. You really need 2 matching knurls in a scissor type knurling tool,or just run the 1 wheel against your metal-which is the best option unless you have a real small lathe [...]
 

jayman

Iron
Registered Member
Joined
Jun 17, 2014
Messages
7
Likes
0
#29
I use straight knurls for my QCTP height adjusters to lock the stop and nut together lock-nut fashion. That way I don't have to reach for a wrench to do it. Coarse knurls in steel work best for me. I am making the Camjack to get the leverage I need for coarse knurls in steel. Will post results when finished.

jayman
 
[6]
5 [7]