Knurling on a small lathe
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Knurling on a small lathe
I would like to make nice knurls without putting alot of sideload on my 6913 Clausing. How do the sissor type knurling tool work? Most of my work will be on 303 stainless and less than 2.5" in diameter. Any sugestions will be appreciated. Butch
Re: Knurling on a small lathe
Butch, I cannot tell you from personal experience, but in theory the load is on the top and bottom instead of the side, so this should be better for the machine as well as the work.
Al Messer
"One nation, under God"
"One nation, under God"
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Re: Knurling on a small lathe
Mine works great on my 13" Colchester
Michael
Michael
Saimp 2 HP 10 X 44 mill, #2 Cin Horz Mill, Cholchester 13" lathe, LeBlond 15" Dual Drive.
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Re: Knurling on a small lathe
Do you feed like in threading? How do you know the proper feed? Any replies will help. Butch
Re: Knurling on a small lathe
Hello Butch,
There is quite a bit to take into account when knurling. I would say the clamp type would be better on small lathes, but since you mentioned stainless,that presents its own problems. Mainly due to work hardening, you need to do this in one shot. It will not take another run with improved results like aluminum or mild steel.
Much of what is seen in tools and such has the start and stop areas reduced in diameter to hide the unsightly parts in dressed up finished ends. It is definitely a production process. One part is a crap shoot of raw luck.
Here is Dorian's and Stafford's links. I just don't do it often enough to store it in my own memory banks.
Dorian
Stafford
DC
There is quite a bit to take into account when knurling. I would say the clamp type would be better on small lathes, but since you mentioned stainless,that presents its own problems. Mainly due to work hardening, you need to do this in one shot. It will not take another run with improved results like aluminum or mild steel.
Much of what is seen in tools and such has the start and stop areas reduced in diameter to hide the unsightly parts in dressed up finished ends. It is definitely a production process. One part is a crap shoot of raw luck.
Here is Dorian's and Stafford's links. I just don't do it often enough to store it in my own memory banks.
Dorian
Stafford
DC
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Re: Knurling on a small lathe
Doug, thanks again for your help and the other guys also. I am building an unlimited return to battery rail gun for benchrest competition. It helps to have good knurls on the adjustment knobs. Butch
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Re: Knurling on a small lathe
Yes, I use the feed and I use pretty slow feed, maybe .007. Don't really know how much difference the feed rate makes. Slow spindle speed and lots of cutting oil.
If you are new to knurling, do you know the formula for knurling?
Michael
If you are new to knurling, do you know the formula for knurling?
Michael
Saimp 2 HP 10 X 44 mill, #2 Cin Horz Mill, Cholchester 13" lathe, LeBlond 15" Dual Drive.
Re: Knurling on a small lathe
There is a thread by John Stevenson over on the Home Shop Machinist BBS.
He shows a knurler that will put cut knurls on a piece of 0.062 wall pipe a couple inches in diameter. You KNOW there wasn't much force there.
It cuts on the side of the knurl wheel.
He shows a knurler that will put cut knurls on a piece of 0.062 wall pipe a couple inches in diameter. You KNOW there wasn't much force there.
It cuts on the side of the knurl wheel.
Re: Knurling on a small lathe
Butch,
The Eagle Rock scissor-type knurling tool works great. I have knurled a fair amount of 303 stainless with good results on my South Bend lathe. Feed a bit slower than cutting, ususally two passes max. I don't like to take more than two passes on any material. One is best if possible. Stainless work hardens as well.
I have experiemented with the formulas for matching the work piece diameter with the pitch of the knurl and have found them worthless. There is so much play in a knurl on its shaft that taking 5 or 10 thous off the work piece is a waste of time in my experience.
Here is my secret: 1) use only quality knurls (throw anything stamped India or China away), and 2) use HEAVY pressure when tightening the scissor attachment on the workpiece, 3) lots of lubricant.
That's it.
George
The Eagle Rock scissor-type knurling tool works great. I have knurled a fair amount of 303 stainless with good results on my South Bend lathe. Feed a bit slower than cutting, ususally two passes max. I don't like to take more than two passes on any material. One is best if possible. Stainless work hardens as well.
I have experiemented with the formulas for matching the work piece diameter with the pitch of the knurl and have found them worthless. There is so much play in a knurl on its shaft that taking 5 or 10 thous off the work piece is a waste of time in my experience.
Here is my secret: 1) use only quality knurls (throw anything stamped India or China away), and 2) use HEAVY pressure when tightening the scissor attachment on the workpiece, 3) lots of lubricant.
That's it.
George
Re: Knurling on a small lathe
Butch,
Knowing nothing about knurling, I bought the scissor type based on statements about that type not putting a side load on the spindle bearings, etc. I just jumped in and started. At first, I would make a few passes, tightening things a little each time. Results were fine. Then I got a bigger lathe and tried just tightening down a lot on the first pass, and everything came out fine in one pass. I don't use a power feed, just feed by hand and feel. No problems. The only thing I would say is that the scissor type will deflect some as you feed, due to slop in the pins holding the knurls and the scissor pivot, and maybe deflection of the scissor arms themselves. If you look at longer lengths of knurling, you will notice that it may appear to be at a slight angle to the axis of the work, and I believe that is due to the deflection. It may be that this would not happen with a very slow power feed and/or using several passes with less pressure on the knurls. You wouldn't see the angle on short pieces like knobs. Also, I've never bothered to try to match the diameter of the work to the pitch of the knurls, and haven't had a problem. I think the overlapping knurling may also be the result of having the pressure on the knurls too light, letting the knurls slip as they are fed along the work. -- Just my $00.02
Knowing nothing about knurling, I bought the scissor type based on statements about that type not putting a side load on the spindle bearings, etc. I just jumped in and started. At first, I would make a few passes, tightening things a little each time. Results were fine. Then I got a bigger lathe and tried just tightening down a lot on the first pass, and everything came out fine in one pass. I don't use a power feed, just feed by hand and feel. No problems. The only thing I would say is that the scissor type will deflect some as you feed, due to slop in the pins holding the knurls and the scissor pivot, and maybe deflection of the scissor arms themselves. If you look at longer lengths of knurling, you will notice that it may appear to be at a slight angle to the axis of the work, and I believe that is due to the deflection. It may be that this would not happen with a very slow power feed and/or using several passes with less pressure on the knurls. You wouldn't see the angle on short pieces like knobs. Also, I've never bothered to try to match the diameter of the work to the pitch of the knurls, and haven't had a problem. I think the overlapping knurling may also be the result of having the pressure on the knurls too light, letting the knurls slip as they are fed along the work. -- Just my $00.02
Curmudgeon